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Alternative anesthesia protocols without use of the neuromuscular block for phacoemulsification in dogs and cats
Correspondence: Stroe Marina-Stefania, DVM, Marina-Stefania.Stroe-Giurca@uliege.be
Cataracts may occur at any age and in any location in the lens. Cataracts can block tapetal reflection and fundic examination partially or completely and are often classified by stage of maturation and cause.
Cataract surgery are facilitated by a central position of the eye ball within the palpebral fissure. A centrally positioned eye is normally achieved by using of neuromuscular blocking agents (NMBAs). NMBAs also decrease the ocular muscle tone and that is very useful because an increased tonus may cause ocular structures to become displaced and distorted and can also influence IOP. Use of these agents necessitates intermittent positive pressure ventilation (IPPV).
Objective: Offering alternatives for anesthesia to perform cataract surgery in dogs and cats without using the neuromuscular block.
The safety of anesthetic protocols consisting of midazolam, tramadol, lidocaine, propofol, fentanyl, ketamine, isoflurane without using the neuromuscular block was studied in 16 cataract surgeries in dogs and cats. The protocol’s safety was expressed by monitoring heart rate, oxygen saturation and pulse rate using pulse oximetry, respiratory rate, end-tidal carbon dioxide provided by capnography, arterial blood pressure using oscillometric method. Assessments were made for quality of induction, maintenance and recovery from anesthesia.
Animals: Sixteen animals, eleven dogs and five cats, all client-owned.
Methods: All animals were examined prior to premedication, were performed blood tests hemoleucogram and biochemistry and monitored during induction, surgery and recovery. Blood samples were analyzed for standard biochemistry panel including glucose, creatinine, ureea, hepatic transaminases and hemoleucogram. Before anesthesia, HR was measured using cardiac auscultation and MAP was measured using automated oscillometry, respectively. Protocols consisting of midazolam, tramadol, or lidocaine iv was performed. IV propofol was administered to abolish the palpebral reflex, produce jaw relaxation and facilitate ETI. Topical ocular administration of oxybuprocaine (Benoxicaine®) 0.4% drops to anesthetize cornea was performed before general anesthesia. All patients received topically sprayed laryngeal 2% lidocaine. The cough response at ETI was recorded.
After intubation, auscultation of heart and lung sounds was possible by means of an oesophageal stethoscope. Pulse oximetry was used to monitor oxygen saturation of hemoglobin in arterial blood and pulse rate. The patient was connected to the inhalational anesthesia machine. The maintenance of anesthesia was achieved using isoflurane like inhalant agent and fentanyl or mixture of fentanyl, lidocaine and ketamine. Respiratory rate and end-tidal carbon dioxide was provided by capnography. Assessments were made for quality of induction, maintenance and recovery from anesthesia by evaluation of the animal’s eye position, jaw tone, heart and respiratory rates and autonomic responses to surgical stimulation.
Results: The purpose of this work was to perform anesthesia protocols without use of the neuromuscular block for phacoemulsification in dogs and cats and make preliminary investigation into safety for patient and to record the advantages and disadvantages. Cataract surgery are facilitated by a central position of the globe within the palpebral fissure. A centrally positioned eye is normally achieved by using neuromuscular blocking agents (NMBAs). NMBAs also decrease the ocular muscle tone and that is very useful because an increased tonus may cause ocular structures to become displaced and distorted and can also influence IOP. But if there is no possibility of using NMBAs solutions must be found.
Conclusion: The aim of the project was to test several variants of anesthetic protocols to compare the various effects of molecules including lidocaine, ketamine, fentanyl, tramadol, propofol, isoflurane have on the organism.
The use of anesthetic drugs without using of neuromuscular block for cataract surgery may be challenging bringing both advantages and disadvantages. The recovery period after a classic anesthesia without neuromuscular block probably is much shorter than that achieved after a curarisation and the probability for hypotension is less likely. On the other hand, without neuromuscular blocking agents we can`t obtain the central position of the eye globe and that implicate make some compromises for the surgery.
Keywords: cataract, anesthesia, phacoemulsification, cat, dog,
Patients with ophthalmic disease, such as cataract, vary from young, healthy animals with congenital cataract to geriatric patients, which may have significant diseases like diabetus mellitus. When planning anesthesia for cataract surgery is important to consider the general health status because there are many patients with concurrent disease and that may present significant challenges for the anesthetist . It required investigations before anesthesia like blood tests and if there are changes ideally their condition should be stabilized before anesthesia. Also need to consider that animals that are blind are more likely to be stressed and fearful compared with patients that have vision, especially if the onset of blindness was acute .
A complete ophthalmic examination should be performed and should include examination of PLR and menace response, Schirmmer tear test, fluorescein stain test, intraocular pressure (IOP) and a fundic examination if possible. A complete physical examination is also pertinent, as cataracts may be related to extra-ocular disease.
Electroretinography and ocular ultrasonography are standard pre-operative screening tools to confirm an eye’s candidacy for cataract surgery. Although pre-operative preparation and postoperative management can be intensive, canine cataract surgery is often successful and rewarding. Risks, time commitment, and financial demands of phacoemulsification should be discussed with the pet owner.
Materials and methods
Eleven dogs and five cats presenting to the ophthalmology service with ophtalmological conditions that cause blindness. All patients received the cataract diagnosis after a full ophthalmic examination. Once a cataract forms, surgery is the only treatment method to restore vision. Phacoemulsification uses ultrasonic energy to fragment and extract cataractous lens material from its capsular bag. Exclusion criteria of the patients were concurrent diseases that could not be stabilized before anesthesia. Any pre-existing medical conditions and drugs administered were recorded.
Food and water were withheld from all patients for a minimum of 12 hours prior to surgery
Animals were gently restrained in a sitting or standing position for drug administration and data collection.
Mydriasis is obtained with topical mydriatic agents (Tropicamide) applied with 2-3 hours before intraocular surgery. Also, topical ocular administration of oxybupracaine (Benoxicaine®) 0.4% drops to anesthetized cornea was performed before general anesthesia. Topical local anesthetics are effective because of a direct action on the cornea and minimizing systemic side effects but their use is limited to diagnostic procedures and intra-operatively as they delay corneal healing, are epitheliotoxic and have a short duration of action .
The position of the animals during surgery was in lateral position for unilateral cataract and dorsal for bilateral cataract (Fig.1). HR was measured using cardiac auscultation and MAP was measured using automated oscillometry.
Anesthesia was maintained with isoflurane in a oxygen delivered via a rebreathing anesthetic circuit with the oxygen flow rate set at 60 ml/kg/min and vaporizer setting of 2%. Oxygen saturation as measured by pulse oximetry, pulse rate and respiratory rate were recorded every 5 minutes after anesthetic induction until the end of anesthesia (vaporizer turned off). Pulse quality was established by manual palpation of the femoral artery and respiratory rate was recorded by observation of the capnogram and chest movement.
Measurement of rectal and esophageal temperature was performed by use of 2 thermistor probes. Rectal temperatures were measured at initial hospital intake and after the end of anesthesia. Once each patient had been induced esophageal temperature was measured by placement of an esophageal thermistor probe and was removed at the end of anesthesia.
The premedication has been achieved with lidocaine 2 mg/kg iv or tramadol 2 mg/kg iv (Fig. 2). All the patients received the propofol-midazolam combination for anesthetic induction. The dose utilized for midazolam was 0,4 mg/kg iv.
The use of ketamine was accomplished in combination with lidocaine and fentanyl for dogs and for one cat was used the ketamine-propofol combination. There is significant interest in this combination of propofol and ketamine because has several benefits in the terms of hemodynamic stability, absence of respiratory depression, post-operative analgesia and recovery . The ketamine dose that was used was low at 0,6 mg/kg iv and was mixed in the same syringe with propofol 3 mg/kg.
Steroidal anti-inflammatory drug (Betametazone, Diprophos®) was administered intraconjuctival at the end of the surgery.
In total sixteen animals (eleven dogs and five cats) were enrolled in the project.
All patients were in good condition of general health just 2/11 dogs were stable diabetic patients and for they measurements have been taken to monitoring the blood glucose level before, during and after surgery.
Premedication with lidocaine 2 mg/kg was performed for 6 dogs and was made observation about cough during endotracheal intubation. IV lidocaine can decrease the incidence of cough during endotracheal intubation but does not appear to have a sparing effect on the dose of propofol required for endotracheal intubation.
Two patients receive tramadol 2 mg/kg iv in premedication, one in combination with lidocaine 2 mg/kg iv and the other just the tramadol. For the patient that receive just tramadol was not observed any changes in the propofol dose.
One dog received fentanyl in premedication and after induction was observed significant respiratory depression compared with the others. Two dogs and 6 cats did not receive anything for premedication.
The diabetic protocol for phacoemulsification consist in tramadol 2 mg/kg iv for premedication, induction with midazolam 0,4 mg/kg and propofol at effect. Maintenance of anesthesia has been achieved using isoflurane like inhalant agent and mixture of fentanyl, lidocaine and ketamine. The glucose level was measured before and every hour during anesthesia.
For all patients, cats and dogs, the induction was performed with propofol and midazolam 0,4 mg/kg and topical laryngeal lidocaine was used prior to intubation. One cat received the ketamine-propofol combination for induction.
The cough response at ETI was observed for 3 dogs, the patient that receive tramadol in premedication and the others that was not premedicated and 2 cats. In propofol anaesthetized dogs iv and topical laryngeal lidocaine attenuated the pressor response to ETI where iv lidocaine reduced the cough response.
Duration of the anesthesia from intubation to extubation was 80 min ±10 min depending of the surgical procedure, unilateral/bilateral cataract.
After induction, a rotation of the eyes towards the internal angle was observed. To achieve the phacoemulsification surgery, the eye was brought to the central position by means of the traction sutures.
Cardiovascular and respiratory parameters were well maintained during induction, maintenance and recovery periods for all patients. All patients receive Ringer Lactate infusion at 5 ml/kg/h. The anesthesia was maintained with isoflurane delivered via a rebreathing anesthetic circuit with the oxygen flow rate set at 60 ml/kg/min and vaporizer setting of 2%. This was completed by analgesia offered by combination of fentanyl-lidocaine-ketamine for dogs and fentanyl CRI for cats. The doses utilized for fentanyl was 4 μg/kg/h in combination with lidocaine 2 mg/kg/h and ketamine 0,6 mg/kg/h and when fentanyl was used alone, the dose was between 5-10 μg/kg/h.
Pulse oximetry was used to monitor oxygen saturation of hemoglobin in arterial blood and was maintained at >95%. MAP was measured using automated oscillometry and was stabilized at 80-110 mmHg.
Respiratory rate, end-tidal carbon dioxide was provided by capnography. The respiratory rate was maintained at 10 ± 5 rpm and the level of CO2 was 45-60 mmHg. All patients breathed themselves spontaneously, just one cat need the controlled ventilation because of the elevated level of EtCO2, up to 65 mmHg and the low respiratory rate.
For all patients the recovery from anesthesia was fast and without any complication. The temperature at the end of anesthesia was 37,2 ± 5ºC.
The ideal anesthetic protocol for cataract surgery should provide central position of the eye, decrease the ocular muscle tone, provide analgesia and narcosis for optimal operating conditions, be safe for the patient and comfortable for the surgeon  (Fig. 5).
Good communication with the surgeon before the procedure and an understanding of the surgeon’s requirements are essential when formulating an anesthesia plan. The patient position with the head lower than the heart should also be avoided and at 15 degrees head-up position during intraocular surgery has been recommended in humans.
Also, the position of the animal during surgery may influence the choice of breathing system and endotracheal tube (ETT). Related to intubation should be remembered that the mouth during tracheal intubation can increase IOP as the choroid process of the mandible moves into the orbit. Care must be taken when positioning patients for tracheal intubation, as pressure may be exerted on the globe while the maxilla is held; this is especially the case for brachycephalic breeds. An armored ETT is recommended to use.
The ability to influence IOP is very important part of anesthesia management. Is necessary to avoid increased IOP because in these circumstances may result in a globe rupture, risk for intraocular bleeding or retinal detachment.
The use of ketamine, a dissociative anesthetic, for ophthalmologic procedures is controversial. Ketamine used alone is likely to significantly increase IOP because it causes an increase in extraocular muscle tone . The good benefits of ketamine administration consist in increased of the amount of circulating norepinephrine, increase in peripheral arteriolar resistance and muscle activity and decrease the extent of redistribution hypothermia . The use of ketamine has beneficial effects on the blood pressure, cardiac output, corporal temperature and contributes to realization of a balanced anesthesia based on a multimodal analgesia. On the other hand, ketamine can increase IOP but considering that in the protocols used in this study was never used alone and the fact that the surgical procedure involves making a break through the incision of the cornea and penetrating the eye globe this pressure can be adjusted naturally without becoming hazardous for the structures of the eye.
Is mandatory to avoid coughing, sneezing, vomits when there is a risk of globe rupture because this can result in an increased central venous pressure . Therefore, drugs like morphine that causes vomiting should be avoided. On the other hand, the use of alpha 2 adrenergic agonist is not prohibited; although may induce vomiting especially in cats the alpha 2 adrenergic agonist can be very useful when we are dealing with uncooperative patients and the risk of globe rupture is bigger because of the stress and manipulation. In this study, for avoiding the coughing response was used lidocaine. Both iv and topical laryngeal lidocaine attenuated the pressor response to ETI and iv lidocaine 2 mg/kg reduced the cough response to ETI in propofol anaesthetized dogs  .
Intraocular blood volume is influenced by intraocular vascular tone (vasodilatation or vasoconstriction), arterial blood pressure (ABP) and outflow of the blood from the globe . Is well known that exist an inverse proportional relationship between arterial carbon dioxide tension (PaCO2) and vascular tone. Increased carbon dioxide tension causes choroidal vessel vasodilatation and an increase in IOP. Hypoxaemia can be detect using pulse oximetry and should be avoided by oxygen supplementation and ventilation. PaCO2 can be monitored by capnography or arterial blood gas analysis and controlled using IPPV. However, inappropriate use of IPPV can increase CVP by increasing intrathoracic pressure during inspiration, resulting in an increase in IOP.
Cataract phacoemulsification is not a very painful procedure except during the incision and suturing of the corneal limbus. Traditionally, most anesthetic molecules mildly decrease IOP by increasing the outflow of aqueous humor. The use of anesthetic induction agents such as propofol, alfaxalone, ketamine and etomidate may all increase IOP. All are ameliorated by co-induction agents like opioids, midazolam or diazepam .
One limitation to the present study was the small number of the patients (sixteen animals – eleven dogs and five cats) used.
In conclusion, if the realization of the neuromuscular block for phacoemulsification is not possible, we can perform anesthesia for this procedure using just the standard molecules like lidocaine, propofol, midazolam, fentanyl, ketamine and tramadol. The recovery period after a classic anesthesia without neuromuscular block is much shorter than that achieved after a curarisation and the probability for hypotension is less likely. On the other hand, after induction, a basculation of the eyes towards the internal angle was observed for all studied cases. In order to achieve the phacoemulsification surgery, the eye was brought to the central position by means of the traction sutures.
The great disadvantage is the fact that without neuromuscular blocking agents we can`t obtain the central position of the eye globe and that implicate make some compromises from the surgeon.
Ana Nemec, DVM, PhD, Dipl. AVDC, Dipl. EVDC; Ana Rejec, DVM, PhD, Resident, Veterinary dentistry
Animal Hospital Postojna, Cesta v Staro vas 20, 6230 Postojna, Slovenia
Case history and clinical signs
A 4-year-old 30-kg female spayed German shepherd was presented due to rapidly growing rostral maxillary mass. At presentation, the proliferative mass, located around right maxillary third incisor and canine tooth was ulcerated and bleeding (Fig. 1). The patient was otherwise healthy with physical exam findings, CBC and biochemistry all within normal limits. Staging options were discussed and the client elected computed tomography (CT) of the head and neck as well as chest CT together with biopsy of the lesion and an abdominal ultrasound.
Imaging and histopathology findings
Pre- and post-contrast CT images revealed an invasive lesion, located primarily around the maxillary canine tooth and extending from the right maxillary second incisor tooth to the mesial root of the right maxillary second premolar tooth, occupying majority of the right nasal cavity and crossing the midline (Fig. 2). CT of the neck and chest revealed no metastatic disease to the regional lymph nodes and lungs, and abdominal ultrasound was also within normal limits.
Histopathology of the lesion revealed spindle-cell neoplasm, with differential diagnoses being fibrosarcoma or spindle-cell amelanotic melanoma, and further immunohistochemistry using Melan A and PNL-2 antibodies was performed and was suggestive of amelanotic melanoma.
A stage III (with no detectable metastasis based on the diagnostics performed) amelanotic melanoma was diagnosed.
Treatment and follow-up
Due to an extensive involvement of the nasal cavity, wide resection was impossible to achieve without significantly impairing the cosmetic appearance and function of the animal, and the client elected palliative-intent extended unilateral rostral maxillectomy to reduce tumor burden (Figs. 3-5), followed by a course of adjuvant hypo-fractionated radiotherapy of the surgical area (6 x 6 Gy twice weekly) 3 weeks after the surgery (Figs. 6-9).
Melanoma vaccine treatment (4-dose, biweekly protocol, then boosters in 6-month intervals) was added to the treatment protocol as an immunotherapy approach to multimodal treatment approach. At all re-checks, the patient was clinically healthy and the most recent re-check head and neck and chest CT revealed no metastases 5 years after the diagnosis (Fig. 10).
Malignant melanoma (OMM) is the most common nonodontogenic oral tumour in dogs. Clinical signs may vary greatly; the tumour is not necessarily pigmented (black). Histopathological diagnostics may be complicated as a tumour may present as amelanotic variant and/or as epithelioid-cell OMM, spindle-cell OMM or mixed-cell OMM. Therefore, immunohistochemistry is often needed to determine the diagnosis. OMM is locally invasive, with 50% of tumours being associated with surrounding bone invasion. Metastases are also common: in 74% of cases, OMM metastasise in regional lymph nodes and in up to 92% of cases in the lungs.
Hence, before any treatment is attempted, a patient with an OMM needs to be properly staged. To evaluate local disease, tumor location is noted and the lesion measured. Diagnostic imaging of the local lesion should include pre- and post-contrast CT of the head, as skull radiographs and/or intraoral dental radiographs will underestimate the extent of the lesion and especially invasion of maxillary tumor into adjacent structures. Magnetic resonance imaging (MRI) can also be considered and PET/CT is becoming available in veterinary medicine as well.
Evaluation of regional lymph nodes may be challenging. Although palpation of the mandibular lymph nodes should be routinely performed, it needs to be realized, that 40% of palpably normal lymph nodes contain metastases. Fine needle aspiration of the regional lymph nodes may be helpful, but reaching the main draining center of the head – retropharyngeal lymph nodes – requires ultrasound-guided approach. Also, it has recently been described, that consensus between cytology and histopathology for staging of lymph nodes in patients with melanocytic neoplasms is poor, and negative result does not rule out metastases. Evaluation of size and contrast-enhancement pattern on post-contrast CT images can be very helpful in evaluating regional lymph nodes for metastases, and PET/CT is also very promising. Excisional biopsy of the lymph nodes is debatable, as complete staging requires removal of all lymph nodes of the head and neck. Excisional biopsy of the sentinel lymph node – technique which is well developed in human medicine – is the goal and determination of the sentinel node will hopefully become easier with advanced imaging techniques.
Staging is completed with evaluation of distant organs for possible metastatic disease, where chest CT is much more sensitive to diagnose pulmonary metastases compared to thoracic radiographs. Full body CT may be recommended, if involvement of abdominal organs is suspected, which is rare in cases of canine OMM, and abdominal ultrasound is usually performed.
Once the stage of the OMM is determined, the treatment approach(es) and prognosis can be discussed with the client. It is worth mentioning here, that scientific data on treatment outcomes for specific stage OMM, especially when several treatment approaches are combined, are scarce. Hence, proper communication with the client is extremely important to present as much as possible information and keep realistic expectations. Generally, prognosis for animals, especially if the tumour arises from dentate areas, is guarded due to early and common metastases. Dogs with small OMM (smaller than 2 cm in diameter, stage I) located rostrally and those without metastases, have the best prognosis. With radical tumour resection (tumour with associated 1 cm of healthy tissues as determined by CT) median survival time was reported to be 723 days and related to tumor stage. It has also been reported, that even incomplete tumour resection (dirty margins) increases survival time. When complete resection cannot be achieved (as was expected in the presented case), or the client declines surgical treatment, or when surgery has resulted in incomplete removal of the tumor, or when regional metastases are present, other treatment options exist, although some studies questioned the benefits of adjuvant therapies. When recommending an adjuvant treatment, most commonly suggested is radiation therapy, which can also be the sole treatment for OMM (local and regional disease). The outcome of radiation therapy depends, as with surgery, on the stage of the tumor as well as on the radiation protocol; most commonly hypo-fractionated radiation protocols are recommended and, when used as a sole treatment of OMM, can result in median survival times a bit shorter than those achieved with surgical treatment. Acute side effects, such as radiomucositis are common, expected and usually resolve with supportive treatment, while late life-threatening side effects, such as osteoradionecrosis or secondary tumors, are rare, but need to be discussed with the client in advance, especially when long-term survival of irradiated patients is expected.
OMM is considered poorly responsive to chemotherapy, but is a highly immunogenic tumor. Although the exact immune mechanisms are not completely understood and are likely individually-specific, several immunotherapy and/or gene-electrotransfer therapy approaches have been suggested for canine OMM patients. Most (clinical) research has been performed on a canine melanoma vaccine (xenogeneic plasmid DNA with a cDNA insert encoding human tyrosinase), which has been shown to be safe, but data on its’ efficacy are conflicting. Although it remains unclear, what (if any) role melanoma vaccine and other treatments played in the prevention of metastatic disease in the case described in this report, it is important to realize, that the outcome of canine OMM treatment may not neccessary be poor. In addition, new multimodal approaches are being developed to treat canine OMM and are changing this disease with historically poor outocme into a chronic disease, at least in selected cases.
Clinical study at Animal Hospital Postojna
At Animal Hospital Postojna we recently began a study titled “Evaluation of immune system response to hypo-fractionated radiotherapy in canine non-operable oral, cutaneous or digital melanoma’ together with the Oncovet Clinical Research Centre in France. The study aims to evaluate immune system response to hypo-fractionated radiotherapy in canine non-operable oral, cutaneous, or digital melanoma and to assess the ability of this therapy to improve the response to immunotherapy in combined treatment. With the client’s agreement, we include dogs (males and females) with malignant melanoma when the tumour cannot be surgically removed, either due to its localisation preventing the recommended wide excision, or the client’s refusal to approve such a procedure. In that case, hypo-fractionated radiotherapy remains the preferred treatment. If you or anyone you know are interested in participating in the study and would like to know more about the study protocol and obligations, risks and potential constraints as well as benefits that we offer if you decide to participate, please, contact us at email@example.com
Brachycephalics are patients that are prone to the increase in the superior airways’ resistance, with the decrease of the airflow at the level of the nose or mouth, which implies higher risks and complications associated with anaesthesia.
The acute obstruction of the superior airways can manifest itself consequently to the overheating syndrome (excessive heat, excessive humidity, after physical effort, hyperthermia), post-detubation or as the worsening of a chronic obstruction.
The overheating syndrome is represented by the the body’s incapacity to dissipate the accumulated heat and can manifest clinically through hyperthermia (> 41° C), dysfunctions of the central nervous system, the activation of the inflammatory mechanisms, hemostasis disorders and initiation of the systemic inflammatory response syndrome (SIRS). The physiopathological cascade can evolve through multiple organ dysfunction syndrome (MODS), acute respiratory distress syndrome (ARDS), acute kidney injury (AKI), disseminated intravascular coagulation (DIC).
The risk factors for the triggering of the overheating syndrome are represented by any anterior episodes, obesity, breed (brachycephalics, Golden Retriever, Labrador), elevated ambiental temperatures and humidity, poor acclimatization, low resistance to physical effort.
Hyperthermia can generate cerebral hypoperfusion, neuronal necrosis, vascular lesions, cerebral edema, haemorrhages, multifocal vascular thromboses. The clinical signs can be spontaneous haemorrhages (petechiae, hematemesis, hematochezia).DIC can appear anytime during the first 24 hours after the incident (close monitoring). Hyperthermia can trigger oxidative stress mechanisms, which can act at gastrointestinal level through intestinal ischemia, cytoskeleton relaxation, increase in intestinal permeability and finally, bacterial translocation. Temperature control is essential for the limitation of clinical manifestations (tachypnea, tachycardia, vasodilation, massive haemorrhagic diarrhea and hematemesis coagulopathies, miocardial hypoperfusion, lactic acidosis, electrolitic disturbances, cardiac arrhythmias, stupor, convulsions, exitus). The patient will have to be cooled simultaneously with the administration of fluids for the control of tissular perfusion and hydroelectrolytic disorders. Crystalloid isotonic fluids will be administered, supplementing, if needed, with colloid boluses, depending on the hydration state, cardiovascular potential and the electrolytic status of the patient. The therapy will continue without interruptions until the patient is stable. In severe cases, it is necessary to start the antimicrobial therapy for restricting the endotoxemia and preventing sepsis ( broad-spectrum antibiotics). The therapy will be completed with gastrointestinal protectors, H2 antagonists (famotidine) and proton pump inhibitors (pantoprazole). Continuous monitoring throughout the therapy is mandatory, because the patients need re-evaluation and consequent adaptation of the therapy.
The key points in the therapeutical management of the overheating syndrome are:
- Oxygen supplementation
- Sedation, general anaesthesia
- Temperature control
- Control of the tissular perfusion and of the acid-base and hydroelectrolytic disorders
- Correction of homeostasis disorders
- Maintenance of the renal function
- Blood glucose monitoring
- Antimicrobial therapyPurpose:
Oxygen supplementation is necessary when the patient first shows up ( starting with the triage phase) in the case of acute respiratory distress syndrome (ARDS), noncardiogenic pulmonary edema or laryngeal edema. Brachycephalics in thermal shock exhibit compensatory hyperventilation or can’t oxygenate themselves enough, consequently to respiratory insufficiency, with high respiratory effort, hyperthermia, muscular exhaustion and, finally, respiratory arrest! The immediate control of hypoxemia initially requires oxygenation through noninvasive methods, followed, if needed, by additional invasive procedures (general anaesthesia with endotracheal intubation, nasal oxygenation catheter, tracheal catheter, tracheotomy/ tracheostomy). High air flow devices can be used for oxygenation (>15l /min.)- oxygen tent/cage, AMBU-bag or low flow devices(<6l/min.)-mask, nasal oxygenation tube, endotracheal probe, tracheal catheter.
Assisted ventilation is recommended either in case of hypercapnia (PaC O2 >60 mmHg) or severe hypoxemia (PaC O2 <80 mmHg or SpO2 <90%) with persistent cyanosis despite having oxygenation levels reaching 100%.Possible complications regarding mechanic ventilation are correlated to the accidental disconnection of the patient, device failures, barotrauma, atelectasis or oxygen toxicity.
Brachycephalics are NOT the best candidates for „a simple sedation”, requiring, in most cases, general anaesthesia protocols. Given the fact that all anaesthetics affect the respiratory function through central depression or through muscle relaxation, a continuous monitoring is necessary, from premedication to the patient waking up from anaesthesia.
Preanaesthetic evaluation will be cautiosly approached, in order to reduce the perioperative mortality, by tracing and evaluating the risks and by adjusting the perioperative protocols. The patients will be premedicated in order to reduce stress, anxiety, agitation, this also leading to a decrease of the doses that are necessary for maintenance. For critical patients, premedication can be excluded, but analgesia must be maintained! A minimal contention is recommended, without a muzzle! For brachycephalics, preoperative preoxygenation is mandatory. For induction, the lowest propofol doses will be slowly administered intravenously. (1.0 mg/kg slowly injected intravenously for the first 15 seconds, then another 1.5-2 mg/kg until reaching the desired effect). The administration of propofol in rapid bolus causes apnea, bradycardia, hypotension and respiratory depression. Propofol reduces the cerebral metabolism, the cerebral blood flow and the intracranial pressure, also alleviating the effects of the hypoxic lesions, and inhibiting lipid peroxidation, having an antioxidative action.
The endotracheal intubation of the brachycephalics must be done with care. It is hard to anticipate the dimension of the trachea by the size of the patients, because they often have hypoplastic tracheas. Anaesthesia is maintained gaseously, ensuring the efficient ventilation of the patient. For avoiding regurgitation, the patients will be positioned slighly forward, with the anterior extremity lifted at . Inhalation anaesthesia protocols can be carried out, if needed, at the same time with the administration of opioids (bolus or CRI) or with locoregional anaesthesia techniques (blockages, infiltrations, epidural etc.).
Secondary effects can appear at high doses of opioids (dysphoria, bradycardia, respiratory depression). For ensuring the polymodal analgesia, opioids, NSAIDs and local anaesthetics can be administred.
Managing the hemostasis disturbances implies the stabilization of the coagulation system, the administration of fresh frozen plasma or anticoagulants, for preventing thromboses.
Maintaining the renal function is possible in the case of patients suffering from thermal shock through maintaining the perfusion and oxygenation of the kidney. Hypovolemia and dehydration will determine the arterial tension and the cardiac output to lower, leading to the decrease of the renal perfusion ( renal ischemia). Lowering the oxygenation at renal level will favor the triggering of acute renal insufficiency. Consequent rhabdomyolysis and myoglobulinemia will damage the kidney even more. If the urine output is low (<1ml/kg/h) even after fluidotherapy, furosemide and/or mannitol can be administered. Mannitol (osmotic diuretic) will reduce the water content of the neuronal cells, will increase the reanl perfusion and diuresis. Furosemide can be administered at 15 minutes after the administration of mannitol. An option for hyperhydration, uremia or different electrolytic imbalances is represented by hemodialysis.
Monitoring the glycemia is very important for critical patients, because the ones that are hypoglycemic have a hard time compensating!
A particular situation is represented by the acute obstruction of the superior airways after detubation. The muscles of the superior airways, which are relaxed post anaesthesia, can favor the appearance of acute obstructions at brachycephalic breeds, together with the inflammation of the larynx and the pharynx, especially after the specific correctional surgical procedures. That is the reason why it is recommended to postpone these patients’ extubation for as long as possible after anaesthesia and to supplement their oxygenation through noninvasive methods (nasal oxygenation probes, prongs, oxygen cage), until they have completely recovered from it. Since the risk of complications is high, it is good to be prepared for a possible reintubation or even for invasive oxygenation methods (trecheotomy, trecheostomy).
Lazar Laura¹, Fodor Lucian²,
¹ʼ²ʼDVM, Veterinary clinic, Happy Pet Timisoara, Romania
Key words: inguinal hernia, intestinal occlusion, acute abdomen, enterectomy
An inguinal hernia is a condition in which the abdominal contents protrude through the inguinal canal or inguinal ring, an opening which occurs in the muscle wall in the groin area.
In dogs, inguinal hernias may be acquired (not present at birth but developing later in life) or congenital (present at birth). Factors which predispose a dog to develop an inguinal hernia include trauma, obesity, and pregnancy.
Most inguinal hernias are uncomplicated and cause no symptoms other than a swelling in the groin area. However, if contents from the abdominal cavity (such as the bladder, a loop of intestines or the uterus) pass through the opening and become entrapped there, the situation can become life-threatening.(2)
Inguinal hernia may evolve to scrotal hernia when herniated viscera pass down the inguinal canal.The internal, or deep, inguinal ring remains patent in intact male animals.(1)
Inguinal hernias can usually be diagnosed by finding the swelling caused by the hernia on a physical examination. However, sometimes contrast radiographs (X-rays) or an abdominal ultrasound are needed to determine which abdominal contents, if any, are entrapped.(2)
A six year old intact male jack russel terrier,fully vaccinated and dewormed suffering an episod of letarghia, voma and apatia for two days.He followed an symptomathic treatment with painkillers and antispastics from his current veterinarian.
The owner became worried because his symptoms got worse, so he was admitted in our clinic as an emergency after the program hours.
his symtomps included:
-severe peritoneal response
-the left testicle was increased in volume
An abdominal ultrasound was performed, was noticed a decreased intestinal motility, with gas presence.
inghino-scrotal hernia/intestinal occlusion
The pacient was initially rehydrated, after stabilization of vital functions was put under general anesthesia and intubated.Surgical intervention was performed, starting initially with the opening of the affected testicle who was enlarged, coloured modified and continuing with medial celiotomy(Fig.1).The terminal part of the small intestine was herniated inside of the spermatic cord (Fig.2).The affected part was aproximatly 10 cm long, with modified tissue and with the rupture of the intestine wall. (Fig 2,3,4) .Following this an enterectomy was performed (fig. 5) with termino-terminal enteroanastomosis.( Fig. 6,).The pacient was also castrated.
The patient condition improved very fast within hours he drank water and ate food.He was also very responsive and playful from the first day.He followed five days of treatment with Metronidazol (20 mg/kg/2×1/day).
The inghino-scrotal hernia is a medical emergency and the intervention must be in the shortest time due to life threatening.
- Jubb, Kennedy and Palmer’s, Pathology of domestic animals, E Book, vol. II, pg.80
Dr Delureanu FlorinCristian
Veterinary Center Otopeni
An ample loss of skin with underlying tissue and exposure of deep components (eg. tendons, ligaments, bones) define a degloving injury. This kind of wounds are most frequent seen on the distal limbs, medial tarsus/ metatarsus. The main cause of deglowing wounds is car accident, special when the animal is dragged or pushed by a moving car. In all of the cases bacteria and debris are present in the wound.
Free grafts are described as a piece of skin detached from an area of the body and placed over the wound. There are two tipes of free grafts when we talk about graft thickness: full thickness (epidermis and entire dermis); partial/split thickness (epidermis and a variable portion of dermis). Skin grafts are using when exist a defect that cannot be closed by skin flaps or direct apposition. Two factors influence skin graft survival: revascularization and absorbtion of the tissue fluid.
A 4 years old female shorthair cat, weighting 3,25kg was presented to our clinic. Before that, the owner was at another clinic for consult and he was disappointed because they recommended euthanasia or amputation of the limb. Besides, the first vet treated the cat with Amoxi+Clavulanic Acid and Nekro Veyxym. The owner said that she went missing for about 10 days.
After a thorough clinical exam we found that all was normal excepting the degloving injury. The back right leg was affected. There was a massive inflammation with infection and a lot of debris on the dorsal surface of metatarsal area and ventral, above metatarsal pad. On the dorsal surface of metatarsal area (Picture 1). Besides, also in the ventral area, another wond proximal to the metatarsal pad and 3 deep holes was identified at the base of second, third and fourth finger (Picture 2). It could be distinguished the chronic aspect. A third lesion was registrated on the same leg, in the medial aspect of the thigh. This wound was deep with a circular shape (Picture 3). We estimated that the lesion occurred about two weeks ago. We register pain and high local temperature after palpation. The cat was stable, normothermic, with normal color on mucous membrane, CRT 3seconds and normal superficial lymph nodes.
Radiograph of the affected back limb
Two x-ray views was made to eliminate bone changes or foreign bodies (Picture 4a, Picture 4b).
Picture 4a, 4b- Specialist describe: Suspected slight thickening of phalanges cortical 1 fingers 3-4 and gently bending them. Soft tissue swelling of the tibio-tarso-metatarsian region.
After evaluation, the initial recommendation include a good wound management under anesthesia. Before surgical debridment (Picture 5a, 5b), culture was done.
Picture 5a and Picture 5b – Dorsal and ventral aspect of the lesions after surgical debridment
Next, wound lavage was initiated with one bag of 500 ml of worm saline (the most easy way to deliver fluids on the wound is to connect the saline bag with a administration set to the syringe and needle with a 3-way stop cock a large amount of liquid is needed to be effective).
Finally, this first stage ends with a wet to dry bandage. A primary wound closure was performed for the lesion placed on the medial aspect of the thigh (Picture 6), after intensive cleaning, removal of foreign bodies and dead skin .
Empirically the cat receive Cefquinome until the result arrive and for pain management we administered Tramadol 3mg/kg and Meloxicam 0,1-0,2mg/kg. The cat recover well after anesthesia.
One day before performing surgery, we recived the culture result. Streptococcus canis (++++) was identified and was sensible to many antibiotics. Amoxicilin+Clavulanic Acid (Synulox) was initiate for general therapy and chloramphenicol ointment (Opticlor-Pasteur) for local therapy.
Next, a full thickness mesh graft was used on the dorsal aspect of the limb due to the length and depth of the wound and the other wound was left for healing by second intention, both being protected by bandages. In the next 10 day the limb wounds was treated in the same manner. Removal of bacteria, granulation tissue formation and the beginning of epithelization were supported by next bandages as follows: ·
Day 1 – wet-to-dry bandage was used after surgical debridment. (this kind of bandages adhere to the wound and remove the little layer of dead tissue when we take off). Soaked in warm saline 1-2 minutes before removing, they were changed after 24hours one to the other. Cotton gauze was the primary contact-layer of the bandage.
- Day 2 and day 3
– moisture retentive dressing (MDR) – calcium alginate (Sorbalgon-Hartmann) was the primary contact-layer. It is good to use when it exist high exudate like in our patient (Picture 7a, 7b).
- Day 4,6 and day 9
– moisture retentive dressing (MDR) – hydrocolloid (Hydrocoll-Hartmann) was the primary contact-layer because the discharge decreased (Picture 8).
Describing surgical procedure:
Preoperative surgical site preparation: The cat was placed in left lateral recumbency, with the wound exposed. The limb was clipped entirely and povidone iodine and alcohol was used for aseptic surgery. Sterile warm saline 0.9% was use for wound lavage. Meanwhile a colleague prepare the donor site in the same manner- lower cranio-lateral thorax (right side). Almost 1mm of epithelium that has started to grow from the wound edges over the granulation tissue was removed using a thumb forceps and a no. 10 scalpel blade (Picture 9). A perpendicular incision was made right at the edge of haired skin with epithelium. The wound was incised all around and after that the epithelium was removed by advancing the scalpel blade under the epithelium around
the wound. Then, undermining was performed around the wound edges. A fragment of sterile surgical drape was used over the wound to get the exact shape. The drape “pattern” was placed to the donor area.
To maintain the wound moist, i placed over it a cotton gauze moistened in warm sterile saline 0.9% while the graft is transferred.
The direction of hair groth was marked with a black arrow above the donor site so that the direction of the hair groth on the graft will be the same as the hair groth direction on the skin surrounding the wound. After that, the margins of the drape “pattern” was traced on the skin. The skin of the donor bed was incised with No.10 scalpel balde and removed using thumb forceps and Metzenbaum scissors (Picture 10). The defect left after removing the graft was primary closed by undermining and advancing the skin edges with walking sutures using 3-0 monofilament absorbable suture material and finally the skin was sutured in a simple interrupted suture manner using 2-0 monofilament absorbable suture (Picture 11a, 11b).
Preparing the graft
The dermal side of the graft was placed on a polystyrene board with a thickness of 10cm covered with a sterile drape and after that we fixed and stretched with 21G needles. The subcutaneous tissue was removed from the graft. Next, made parallel incisions was made in the graft, 0.5-0.7cm long and apart (Picture 12). At the end, the graft was placed on the granulation bed and sutured with 4-0 monofilament nonabsorbable suture in a simple interrupted suture manner. Additional tacking suture was placed to ensure the expansion of the mesh incision and allow the fluid drainage (Picture 13).
Choosing the right bandage after grafting and aftercare
It is important to use a nonadherent primary dressing. My initial choise was Grassolind (Hartmann), is sufficiently porous to allow easy passage of exudate from the wound surface, preventing maceration of surrounding tissue (Picture 14). The ventral metatarsal wound maintain hydrocolloid dressing (Hydrocoll-Hartmann) as primary layer. After that, a thin layer of chloramphenicol oinment (Opticlor-Pasteur) was used all around both wounds and over the graft.
Over the first dressings was applied 5cmx5cm compress (Medicomp-Hartmann) and a roll gauze was the second layer. After a few laps of gauze stirrups was placed to secure the bandage in place. Extemporaneous half “clamshell” splint (Picture 15) was made from plastic material wich was curved in such a way that the limb was fixed in semi flexion. The splint is a little bit longer than the extremity of the pelvic limb (“toe-dancing” position), thus provide a maximum relief pressure. In the proximal area, under the splint, I put cotton to prevent pressure injuries on the caudal aspect of the thigh. Applied from proximal to distal and with moderate tension, elastic warp was the final protective layer of the bandage and it was secured at the proximal end with tape.
The bandage was changed in day 1, 3, 5, 7 and 10 post op. In day 10 the suture material was removed from the graft and from the donor site. From day 17 to day 29 hydrogel (Hydrosorb-Hartmann) was used as primary bandage layer and the bandage was changed from 4 to 4 days. In day 29 no discharge was present in the bandage; the wound was completely healed and 0,2-0,4 mm of hair was present in the center of the graft.
A delayed healing occurred at the wound in the ventral region (Picture 16). From day 29 to day 59 epithelization has advanced very hard and granulation tissue has captured an appearance of ulcer (in this time the wound was asepseptic prepared and hydrocolloid and hydrogel was used as primary layer bandage and without the splint). In day 59 the wound was refreshed on the surface with a scalpel blade and laser therapy (Picture 17a) and medical Manuka honey (Picture 17b) was used daily for 14 days. After that, a complete healing was reached.
Illustrating wounds evolution after surgery
Day 11 after honey and laser therapy
Day 16 after honey and laser therapy
Comparing day 1 and after 3 Months
- MOISE ADRIANA
SIGNALMENT AND HISTORY
- FEMALE CAT , 2 YEARS OLD WAS PRESENTED FOR A CLINICAL EXAMINATION WITH HYPERSALIVATION , HALITOSIS, LACK OF APPETITE FOR PROCESSED DRY FOOD
-THE CAT HAD NORMOTHERMIA AND A NORMAL BODY WEIGHT
-AT PHYSICAL EXAMINATION SHE PRESENTED ULCERATIVE LESIONS IN ORAL CAVITY, LOCALISED ON GINGIVAL MUCOSA, INFLAMATION ON PALATOGLOSSAL FOLDS AND PHARYNGEAL WALLS
-EDEMA WAS PRESENTED AND LOCAL LYMPHNODES WERE REACTIVE TOO
LESIONS WERE PRESENTED BILATERAL ( photo 1,2)
-FELINE LYMPHOPLASMACYTIC GINGIVITIS-STOMATITIS COMPLEX
-FELINE CALICIVIRUS INFECTION
-FELINE HERPESVIRUS INFECTION
-FELINE EOSINOFILIC SINDROME
-FELINE CALICIVIRUS Ac –NEGATIVE
-FELINE IMMUNODEFICIENCY – FIV Ac-ELISA –NEGATIVE
-FELINE LEUCHEMIA –FELV Ag-ELISA – NEGATIVE
-THE CORONAVIRUS Ac TITRE – INCREASE
-CITOLOGY FROM IMPRESSION SMEAR – INCREASE NUMBER OF BACTERIA AND NUMEROUS ACTIVE INFLAMATORY CELLS
BLOOD TEST (BIOCHEMISTRY) WAS NORMAL
-HEMATOLOGY REVEALS LYMPHOCYTOSIS
-CYTOLOGY AND HYSTOPATOLOGIC EXAM CONFIRMED THE DIAGNOSTIC – FELINE LYMPHOPLASMACYTIC GINGIVITIS STOMATITIS COMPLEX
FELINE LYMPHOPLASMACYTIC GINGIVITIS STOMATITIS COMPLEX
UNTIL WE GOT THE RESULTS THE OWNER BEGINS TO TREAT THE CAT WITH
-STOMODINE GEL TWISE A DAY, 14 DAYS
-CEFA CURE 20MG/KG/DAY, 10 DAYS
-SYNBIOTIC D-C 1CPS/DAY, 10 DAYS
-K9 IMMUNE SUPPORT CAT
-AFTER 10 DAYS OF TREATMENT THE INFLAMATION BEGAN TO REDUCE BUT THE ULCERS DO NOT HAVE THE TENDANCE OF HEALING
AFTER WE GOT THE DIAGNOSTIC THE CAT GETS THE FURTHER TREATMENT
-PREDNISON 2MG/KG/DAY, 5 DAYS; THEN 1MG/KG/DAY , 5 DAYS FOLLOWEDBY EVERY OTHER DAY
-STOMODINE GEL TWICE A DAY LOCAL
-HONNEY WITH PROPOLIS LOCAL
WHEN SHE CAME FOR THE EVALUATION AFTER 5 DAYS OF TREATMENT WE SAW THAT THE LESIONS HAD A TENDANCE TO REDUCE, BUT AFTER ANOTHER 5 DAYS THE LESIONS WERE EXACTLY THE SAME AS THE BEGINNING
-WE DECIDED TO INTRODUCE CYCLOSPORINE IN THE TREATMENT
-THE CAT IS PERMANENTLY MONITORIZED ; HLG IS MADE EVERY 2 WEEKS
-AFTER 2 WEEKS OF TREATMENT THE LOCAL INFLAMATION BEGINS TO REDUCE
-AFTER 1 MONTH OF TREATMENT THE LESIONS FROM ONE SIDE WERE HEALD
-THE CAT IS STILL UNDER TREATMENT
-THERE IS NO SIGN OF SECOND EFFECTS OF CYCLOSPORINE
If you have already realised that providing high quality veterinary medicine services to exotic pets can increase your turnover and enhance clientele then let me congratulate you! This article will give you an easy step-by-step guide to follow in order to make the best of your new venture.
Have you wondered why so few vets are seeing exotics? Some frequent explanations include:
- Most vets get little training in caring for exotic pets and as a consequence they get stressed when having to see an exotic pet. Many clinicians will refuse to see them unless it’s a first aid situation and the ones that do, probably won’t generate sufficient income to cover their time.
- If surgical intervention is required, the price for the time spent with an exotic animal, a rabbit for example, is almost half that compared with the same time spent caring for a dog or a cat.
It is no surprise that exotic animal medicine is not high on the preference list of any sensible practice owner. But this is because you’ve been doing it all wrong!
These steps will guide you in starting up a successful exotic animal department in your clinic.
- Don’t cut corners, practice good quality medicine
The slogan “Gold standard practice” is unfortunately overused these days. Many practices advertise gold standard protocols, however these apply to dog and cat patients only. When it comes to seeing an exotic pet, basic investigations like a simple blood sample or a faecal test are often not even offered to owners and this is where the clinic is losing money and clients.
Through having your staff trained and consequently confident in carrying out specific procedures on exotic pets this will not be the case.
Protocols for different alignments should be in place for exotic animals as well as for small mammals to secure the best care for all pets. Having protocols in place will facilitate a fast treatment set-up at the best standard, easily followed even by inexperienced vets when there’s no support around.
There are a wealth of specialised procedures to be carried out on exotics and trained veterinarians and/or nurses will be able to offer all this to customers, generating more income for the practice.
Encouraging best care practice will stimulate your staff to keep up to date with their training; practice high standard procedures and good outcomes will not stay unnoticed for long. As a consequence more owners will register with your practice. Your staff will be delighted to be at the top of their job taking pride in what they do.
- Train your staff
Having your staff trained into caring for exotic animals their procedures can be fast, successful and stress free. Because major differences exist between exotic and small mammals, one must have specialised training in order to be able to look after exotics.
Knowledge and confidence is what you need in your team. Offering a generous list of fairly priced specialised procedures will generate more work for the practice and can only be an asset comparing with your competitors (I will return to this later in this article).
Naturally, trained staff will exude confidence and gain owners trust. Consequently, owners will be more likely to agree to more high risk or specialised procedures which they might otherwise hesitate upon; again, thus increasing your revenue.
Practices with trained staff to care for exotics are scarce, so letting your customers know what your team can do and what their level of training is, will not only serve to retain existing clients but will also attract new customers to the practice, and these new customers will often have more than one pet. And who doesn’t like a growing client base?!
- Charge a fair price for your services
Establishing a fair price is the key factor in setting up your business for failure or success.
Firstly, it is important to understand that there is no relation between the purchase price of a pet and the costs for its medical treatment.
Some people will adopt stray dogs and request for expensive laparoscopic rather than traditional neutering. No surgeon would hesitate to give them an accurate estimate. However when contemplating performing a tortoise spay, most surgeons will doubt the owners’ willingness to accept the surgery as a first option because of the costs involved. However, this is only our assumption!
Set your pricing to charge fairly for your time, your assistants’ time, the materials used and not least for your skill.
Pricing all materials used (like catheters, swabs, gloves etc.) separately will show owners how much the consumables cost, otherwise owners have no idea how much an urinary catheter is and not giving them a detailed bill can lead to confusion. Pricing of the consultation fee should cover time spent with the client and overhead costs such as rent, electricity, water etc. Pricing for the individual procedures carried out (like “placing an IV catheter” or” blood collection”) must cover your salary costs and the cost of ongoing training. The message here is that all costs should be factored in rather than just absorbed.
To your advantage is the fact that few veterinary surgeries offer good quality medicine for unusual pets. If you are clearly the best at it, you have little competition. There is nothing inherently wrong with being expensive but you should not forget that this approach requires continuous training and investment in equipment.
My experience has shown that owners shopping around for price rarely become good, loyal clients. They will always be difficult to convince to agree to investigations and will be likely to complain more if things don’t work out immediately (this is natural, because they can’t afford to spend more money for further tests if needed). The question is not whether you need these clients, but whether you can afford them. Charitable care organisations might be more appropriate for financially challenged clients.
Customers shopping for quality and excellence in veterinary care will be yours for life and will pay fairly for your services because they understand and appreciate your approach. Make this group your target clientele and your efforts will pay off.
Working with exotic pets requires that some adjustments to the hospital facilities and dispensary are made. Exotic pets are escape artists, easily stressed and some of them are poikilothermic, will need special hospitalisation facilities like a vivarium or even an incubator. With a modest budget you’ll be able to adjust your clinic to their needs (to keep costs down you can consider buying vivariums, loupes or surgical instruments second hand).
Most medication used is similar to that for small mammals, however, be aware that dosage is not, so be careful and make sure to consult your exotic medicine library.
ARAV.ORG, AAV.ORG , AEMV.ORG are prestigious, reliable sources of information, so do invest in membership to this organisations. This will give you access to updated care sheets, up to date research data, specific event information and most important, a lot of colleagues to get in touch with in case you need advice on your cases.
There’s not much gain, except of course personal gain, in being very good at your job if nobody knows about it. In order to keep the business going one should make sure existing and prospective clients know about the range of services the clinic is offering.
You could periodically inform clients about any new equipment purchased and about what training your staff has undertaken. This will not only act as a “refresher” on what your service offering is but will also spread by word of mouth. You may be surprised to find how much impact the users of specialised forums have when a new exotic pet owner is looking for a knowledgeable vet. Make sure your name appears there, next to a good review of course.
Always remember to keep your colleagues informed about your services. Referral cases are a good source of income and a great way of practicing your specialist skills. Organizing open days and continual professional development courses will keep you on the radar of colleagues and clients alike, they should know that you exist and are doing well.
An unusual pet can easily become a news subject and this can get you free advertising. Don’t be shy, let the world know about your successful cases, consider local newspapers, TV and radio as well as social media.
- Stay at the top
Don’t ever stop learning.
Exotic animal medicine is developing fast, trends are changing and new protocols are being elaborated at an incredible speed. Refresh your library (very important: change your Carpenter’s Exotic Formulary with any new edition) periodically.
Re-evaluate your protocols every year, attend refresher courses, learn new surgical procedures, and stay updated. When you are the best you can be, you have no competition other than yourself.
Enjoy your success!
Corresponding authors :
Dr. Vladislav Zlatinov, Dr. Aglika Yordanova (Clinical pathologist), Dr. Nadejda Petrova (Anaesthetist)
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
Rib tumors are uncommon in small animals. Osteosarcoma (OSA) is the most common (73%). Other types include chondrosarcoma (CSA), fibrosarcoma (FSA), hemangiosarcoma (HSA).
Rib tumors tend to occur in large breed dogs and the usual location is in the costo-chondral junction. Radiographic changes include lysis, sclerosis, or a mixture of lytic and blastic patterns. Intra-thoracic invasion of adjacent pericardium and lung lobes is relatively common, so CT scans are recommended to determine the location and extent of the tumor, planning of the surgical resection, and clinical staging for pulmonary metastasis1.
Chest wall resection is recommended treatment for the rib tumors 2. The surgical approach is the identical to intercostal thoracotomy, but caudal and cranial margins include a minimum of one intercostal space and rib, while ventral and dorsal margins should be a minimum of 2 cm from the tumor. Because of the large defect present, a need for autogenous and/or prosthetic reconstruction techniques is often necessary. Autogenous reconstruction techniques include the latissimus dorsi and external abdominal oblique muscles, and diaphragmatic advancement following resection of caudal rib tumors 3. Prosthetic reconstruction with non-absorbable polypropylene mesh, alone or in combination with autogenous techniques, is recommended for large defects. Autogenous reconstruction is preferred in humans because of a high complication rate associated with prosthetic mesh, such as infection and herniation. These complications are rarely reported in dogs following chest wall reconstruction with prosthetic mesh. Up to six ribs can be resected without affecting respiratory function in dogs 4.
Thoracic surgery in small animals is considered a painful procedure, resulting in alterations in pulmonary function and respiratory mechanics. Appropriate analgesic protocol may improve outcomes. Systemic administration of opioids and NSAIDs, intercostal and intrapleural blocks, and epidural analgesia are among the most common options for pain management after thoracic surgery in small animals 5.
A 10 years old male pitbull dog, weighting 24 kg was presented to us. The owners had been to three veterinary consultations before, the chief complaint being lameness at the right front limb. The cause was suggested to be a “lump” on the right thoracic wall. Based on an X- rays study and clinical examination, so far the owners were discouraged to pursue the further surgical treatment, because the procedure was supposed to be too aggressive and painful. The dog was prescribed palliative NSAIDs therapy.
We did a thorough clinical exam, revealing normal behaviour, good over-all body condition; signs of multiple joint arthritic diseases were found- elbows and stifles decreased ROM and capsules thickening. On the right cranio- ventral thoracic wall we found protruding, egg- size oval mass, widely and firmly connected to the rib cage (Fig.1).
Radiograph of the right elbow revealed advanced elbow arthritic changes.
Additionally, orthogonal thoracic radiographs (+ oblique one) were done, demonstrating large infiltrating mass, with heterogenous lytic and proliferative mineralised pattern, originating at the costo-chondral junction of the 4-th rib (Fig.2).
A fine needle aspiration was done and evaluated (Fig.3).
The pathologist remarks:
“Clusters of fusiform mesenchymal cells, with obvious signs of malignancy- pleomorphism, increased anisokaryosis and anisocytsosis, basophilia, multinucleated cells . Occasional osteoclasts, macrophages and neutrophils were noted. No osteoid/chondroid was found in the examined material. The tumor was classified as malignant mesenchymal– fibrosarcoma, chondrosarcoma or osteosarcoma.”
A computer tomographic study was accomplished and the mass’s margins investigated carefully. A mineralised tumor centre (from the distal third of the 4-th rib) was found; also soft tissue aggressive expansion in the neighbour intercostal spaces -3-th and 5-th. Typically for the chest wall masses, there was an eccentric growth- the 2/3 of the mass volume protruding into the throracic cavity, extruding the pulmonary parenchyma and contacting the heart on the right side. No lung metastases were noticed on the scans (Fig.4, video 1).
Complete blood work was done and found normal. Including normal Alkaline Phosphatase level, considered favorable prognostic factor.
After a discussion with the owner, a decision for surgical resection was made.
Premedication with Medetomidine and Butorphanol was used, followed by Propofol induction. The maintenance was sustained by Isoflurane and Ketamin drop in the fluid sack.
Peri-operative analgesia, Anesthetists remarks
The thoracic wall resection is considered very painful procedure, so a corresponding analgesic strategy was built and applied. A continuous post operative segmental epidural analgesia application was provided. T13—L1 epidural puncture (by Tuohy needle), was done and an epidural set catheter (B. Braun) was inserted till the 5-th thoracic vertebra(Fig.5-6). The catheter was safely attached and maintained for 48 h post op, during the patient’s stay in the clinic. The agent delivered through, was Levobupivacain (0,5 %), one 1ml every 4 hours, including pre op.
After the mass removal, a soaker catheter was sutured at the ribs resection edges; another one was applied between the skin and muscle flap, covering the defect. Both catheters were connected to an elastomeric pump (B. Braun), delivering locally 5 ml/h of 1% Lidocain for 96h (including outpatient period) post operatively.
The rationale behind additional soaker catheters was to suppress maximally the nociception transfer, including the sensation through the non- blocked cervical spinal nerves. Also we contemplated- removal of epidural catheter at the time of discharge, but leaving the delivery pump, providing residual local analgesia.
Cimicoxib (Cimalgex) was prescribed for 10 days post op. No opioids were used in the recovery period.
Surgical protocol (surgeon remarks)
After macroscopic mapping and drawing, a rectangular shaped, full thickness (skin, muscle, ribs and pleura) en bloc excision was done (Fig.7). This included partial ostectomy of 3-th, 4-th and 5-th ribs. Caudal intercostal thoracotomy was performed first, permitting evaluation of the intrathoracic extent of the tumor. Special attention was applied at the proximal approach to ligate safely the three intercostal arteries and veins. No visceral lung pleural or pericardium adhesion were noticed. Careful electrocautery haemostasis was done at the muscles’ cut edges. The removed mass was macroscopically evaluated for “clean” margins, and a reconstruction of the large defect was preceded (Fig.8). A double (folded) polypropylene mesh (SURGIPRO®TYCO) was sutured to the wound edges, using simple interrupted pattern (3-0 PDS material). A latissimus dorsi muscle flap was advanced to cover and “seal” the defect (Fig.9). The air content was evacuated with aspirator on the final closure; no chest drain was left in the thorax. Two soaker catheters were applied in the wound; the skin was closed by double pedicle advanced flap technique and simple interrupted pattern (Fig.10).
Post operative care and follow up
The dog’s chest was loosely bandaged; the elastomeric pump and epidural catheter were securely fixed to the body(Fig.11). I.v. antibiotics and fluid support was continued for 24 hours post op.
Provided very effective local analgesia- the dog revealed excellent comfort immediately after the surgery (video 2,3,4). We paid special attention to any pain signs- excessive vocalization, hyper-excitement, panting, tachycardia, behavior abnormalities, etc. No such were present and the patient started eating the next day after surgery; it was discharged 48 after the procedure. No ambulation deficits were seen with the Levobupivacain application. The elastomeric pump was removed on the 4-th day. Mild to moderate serosanguineous discharges from the wound were present for 10 days after the surgery.
On the 14 days recheck the wound was healed and the sutures were removed; the patient showed excellent clinical recovery (Fig.12).
The surgical excision is considered the first treatment of choice for malignant rib tumors, but a question about the long term prognosis and rationale behind an aggressive surgery could be raised. As mentioned above, the most common rib tumors are osteosarcomas (OS) and chondrosarcomas(CS). They have quite different prognosis- OS is rarely cured, whereas CS could be cured with surgery alone. Dogs with osteosarcoma that have elevation of the Alkaline phosphatase level have a much lower median survival times 6. Chemotherapy significantly increases the survival of dogs with rib OS- from a few months to about 9.5 months. Roughly survival time is increased 4 times with chemotherapy + radical resection, compared to surgery alone. Chondrosarcomas have a very good chance to be cured with surgery alone with median survival times exceeding 3 years. The other common type -fibrosarcoma and hemangiosarcoma have intermediate metastatic potential between the other two. Survival times ranging from 120-450 days with chest wall resection alone 7.
Dealing with motivated owners, a patient in good general health, with normal AP, and need for moderately large rib case resection size, we found good indications for tumor removal without preliminary histological verification. We suggested acceptable life expectancy in the worst tumor type scenario (the option for chemotherapy was available). While respecting previous vets’ opinions, we took into consideration the stated in the literature fact that dogs tolerate removal of a large portion of the rib cage very well.
Despite all this encouraging decision making facts, we would have fought ethical issues in a scenario we weren’t able to provide sufficient peri-operative analgesia of the patient. Except the ethical side, the pain associated with thoracoectomies may have potentially lethal consequence for the patient cardiopulmonary status after surgery. A thoracoectomy requires a very painful excision, involving multiple muscle layers, rib resection, and continuous motion as the patient breathes. Sub-optimal management of pain has major respiratory consequences. Inspiration is limited by pain, which leads to reflex contraction of expiratory muscles, and consecutively to diaphragmatic dysfunction (decreased functional residual capacity and atelectasis, hypoxemia).Treatment of acute post-thoracotomy pain is particularly important not only to keep the patient comfortable but also to minimize pulmonary complications 8.
In the veterinary literature there are suggestion for various types of analgesia provided after thoracotomies- intercostal blocks, intrapleural lidocaine, incisional pain soaker catheters9; systemic agents as NSAIDs, opioids, NMDA antagonists (ketamine),etc. There is plenty of space for objective evidence based studies, proving the best analgesic protocol, yet.
In the presented case we applied sophisticated but uncommon noxious stimulus blockage strategy. The thoracic epidural catheter insertion is technically demanding procedure but it is very powerful tool for both intra and post operative pain control 10. Even more, it allows even preemptive pain blockage. So-called preemptive analgesia is intended to prevent the establishment of central sensitization caused by surgery induced injuries. Evidence from basic research has indicated that analgesic drugs are more effective if administered before, rather than after, a noxious stimulus. Human studies report that the area of post-thoracotomy pain is more discrete and largely restricted to the site of surgery. Hence, any benefit of preemptive epidural analgesia is, theoretically, more apparent in thoracic surgery than in abdominal surgery.
It is interesting if the present tumor or the arthritic elbow lesions caused the primary clinical sign- front right leg lameness. Lameness of the forelimb had been described with costal tumors, located within the first four ribs 11. Possible mechanism is pain translation to the nerves to the limb, mechanical interference with movement or invasion into the muscles of the forelimb. After the surgical excision the owners reported lameness disappearance, supporting the tumor as the real cause.
Excision of malignant chest wall masses could be very successful. It is feasible to achieve clean cut margins; large residual wall defects could be managed with combined reconstruction techniques. Never mind the aggressive character of the procedure, an excellent patient comfort should be achieved with a combination of thoracic epidural and local wound nerve nociception blockage, as in this case.
Just before the submission of this case report the histopathology result was received. It concluded:
Mass, originating from spindeloid to pleomorphic cells, highly cellular. The cells were round, organized in bundles and solid formations. There was moderate to marked anisokaryosis and anisocytsosis; mitotic figures frequently present, multifocally there is osetoid production.
Diagnosis: Malignant pleomorphic neoplasia, suspicious for osteosarcoma.
Long term prognosis:
In the case, no local recurrence is expected because of the wide margins excision. Generally the median survival time (MST) for dogs with rib OSA is 90-120 days with surgery alone and 240-290 days with surgery and adjunctive chemotherapy, and death is caused by distant metastases. Age, weight, sex, number of ribs resected, tumor volume, and total medication dose do not influence survival disease-free interval 12.
A chemotherapy protocol is already being contemplated:
Carboplatin 300mg/sq.m.; 4 treatments q 21 days (Withrow and MacEwen Small Animal Clinical Oncology,2007)
If available, the long term result and the survival time of the patient will be followed and shared through the journal.
Dr. Vladislav Zlatinov
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
Referring vet: Dr. Jordan Jordanov
Most commonly the pneumothorax in small animals is caused by trauma 1. It could be open or closed; closed traumatic pneumothorax is often the result of blunt trauma (HRS, automobile accidents, etc.). The mechanism includes a chest compressed against the closed glottis, the airway or lung parenchyma can rupture with resultant air leakage.
When there is no evidence of trauma, air leakage from the lung parenchyma is termed spontaneous pneumothorax. This is relatively rare but potentially lethal condition in small animals. The most common underlying causes are pulmonary bulla, subpleural blebs/emphysema (68% of dogs); neoplasia (11% of dogs); migrating plant seeds; pulmonary abscesses; feline chronic allergic bronchitis; chronic pneumonia; heartworm disease. Siberian Huskies and large chested breeds are overrepresented for the condition2.
In internal pneumothorax, the trachea, bronchi, alveolar ducts could be the source of leakage. The alveolar-pleural fistula (APF) is a communication between the pulmonary parenchyma distal to a segmental bronchus and the pleural space, while a broncho- pleural fistula (BPF) is a communication between a main stem, lobar, or segmental bronchus and the pleural space3.This distinction is important because the treatment for the two types could vary. Indeed in the veterinary literature there are not too many publications, regarding incidence, therapy, etc. of APF.
Six years old, large (40kg) mix breed dog was presented to us with clinical signs of respiratory distress. The difficult breathing had started suddenly 48 hours ago. The referring veterinarian had done primary diagnostics- chest X -rays and blood work. The radiographs had revealed bilateral pneumothorax; thoracocentesis has been accomplished several times, every time evacuating more than one liter of air. The owner didn’t report any primary trauma. The day before the onset, the dog was treated with parasite prevention drug-Ivermectin 300 ug/kg , s.c.
Our clinical examination revealed anxiety, tachypnea- frequent (120/min) shallow breathing, distant breath sounds bilaterally, mild fever- 39.5. The patient was over- all hemodynamically stable- normal mucous membranes, strong femoral pulse.
After sedation with Butorphanol + Midazolam (i.v.), thoracocentesis was done at the right 10-th intercostal space. Almost two liters of air were removed.
Orthogonal chest radiographs (just after the centesis), revealed residual pneumothorax, left lung lobe collapse (atelectasis), right shifted cardiac silhouette (Fig.1). Pleural fissures were detectable, but no significant pleural effusion was visible; the lung pattern showed mild signs of diffuse alveolo-interstitial pattern, more pronounced in the right hilus area.
A serological Diroffilaria test (Anigen, Bionote, Seul, Korea), done by the referral veterinarian went out positive. Nevertheless, the disease was not confirmed by us- the SNAP 4Dx Test (Idexx comp.) and microfilaria blood smear tests came out negative. Larvo/ovoscopic test (done 6 days later) was negative.
Working algorithm Within the next 8 hours, several thoracocentesis and air evacuations were accomplished, demonstrating the significant air leakage present. The underlying cause was not evident- a spontaneous rupture of a lung lesion (bulla) was supposed. A bronchoscopic or thoracoscopic diagnostic options were not available. A CT study could be used but needed transport to another facility, which was evaluated as too risky. Because of the lack of any signs of lung sealing within 56 hours, an open chest surgical exploration was planned and accomplished.
The patient was pre medicated with Acepromazine/ Butorphanol combination- i.m., low range doses. After 10 minutes of hyper oxygenation the patient was induced in anesthesia rapidly (Diazepam/ Propofol) and intubated as fast as possible. The maintenance was achieved by Isoflurane gas (2-3%) and Ketamine drop. Positive end-expiratory pressure (PEEP) of 15 cm H20 ventilation was applied to the patient, using anesthetic ventilator (Midmark Matrix). The hemodynamic parameters- saturation, pulse rate, blood pressure was closely monitored during the whole surgery; no anesthesiological incident was met. The PEEP was adjusted ( up to 25 cm H20), accordingly to the desired lung hyperinflation after chest opening.
A standard ventral median sternotomy approach was used. The sternum was osteotomised (with oscillating saw) in the mid line – from the 3-th to 7-th sternebra; later the approach was extended further caudally , leaving intact the end part of the xiphoid process. Two automatic wound retractors were placed cranially and caudally, achieving excellent approach to all chest structures.
A thorough cavity inspection was accomplished. No free fluid or obvious air leakage was found. Chest walls and heart had a normal surface and structure. The lungs had a normal surface, structure and inflation except one collapsed lobe area. The pathology was found in the caudal part of the left cranial lung lobe- atelectasis , with lack of parenchyma inflation. On the dorsal surface there were three small (1 mm) confined lesions areas with serosal surface defects,filled with granulation tissue (Video 1)
A bubble test was accomplished- flooding the chest with warm sterile saline and searching for bubbles during positive-pressure ventilation (up to 40 cm H20). Surprisingly no source of air leakage, including the lesion area, was found.
A second careful and thorough lung exploration was done, but did not reveal any other areas in question. Finding the visible pathology , we proceeded towards partial lobectomy of the distal collapsed caudal part of the cranial left lobe. One relatively big bronchus and blood vessel were encountered proximally and ligated individually. The resected area was first sutured with continuous overlapping suture (3-0 PDS). The edge of the incision is over sewn in continuous pattern (4-0 PDS). The sutured sites were tested for leakage again. The lung tissue was separated for histology examination.
Single chest tube was placed before thoracic cavity closure. The thoracotomy was closed routinely, using several full cerclage wires, compressing tightly the osteotomised stenebrae
Postoperative care and follow up
Peri operative analgesia was provided using multimodal approach:
NSAID (Meloxicam s.c.) – pre and post op
Transdermal Fentanyl patch 100 μg (applied 4 h pre op),
MLK (Morphine, Lidocaine, Ketamin) i.v. infusion for 10 hours post op
Local pleural infiltration- 20 ml Levobupivacaine (2,5 mg/ml) in the chest tube every 6 hours.
Continuous air suction was not applied but the chest tube was tested and air evacuated every 2 hours.
The patient showed fast anesthetic recovery with good pain control after the procedure (comfortable laying in sternal recumbence).
The air presence was monitored carefully. After 2 hours of negative finding, an abundant air accumulation started, just as the preoperative status. With the frequent air evacuation, the next 24 h the patient was respiratory stable with occasion onsets of tachypnea. The chest tube was closely examined, and found adequately airtight.
Significant air leakage (>500 ml/h) was appreciated in the next 24h after the surgery, with no tendency of rate deceleration. This let us look for a major broncho-pleural fistula with hidden /complex localization. We used an uncommon diagnostic technique- contrast bronchography. After induction in short light anesthesia, the dog was intubated and 3,5 ml Omnipaque (Iohexol 350 mg/ml) were injected through the endotracheal tube, with the head in elevated position. The procedure went uneventfully; the X rays, following 2 minutes of Ambu bag hyperventilation revealed normal bronchial tree, without noticeable pathology(Fig.3).
Second explorative surgery
Considering, that we didn’t adequately addressed the air leakage, and after a fair discussion with the owner we reluctantly decided to go for a second explorative surgery.
The same anesthetic protocol was used; we approached the cavity through the recent thoracotomy wound. The lobectomy site was explored, showing perfect sealing and early signs of fibrin formation on the edge. The chest tube intercostal passage looked smooth and nice without soft tissue laceration.
This time, all the lung lobes showed normal inflation and again a frustrating lack of any leakage signs. Special attention was payed on to explore the obscure hilus lung areas. Two saline/bubble test were accomplished without result. At the end (after 30 minutes exploration) an air leakage was demonstrated by an accidental left lung lobe maneuvering, while the chest still filled with saline. We found a single, small (0,5 mm) , barely visible, smooth margins (obviously epithelised) opening on the dorsal surface of the cranial left lung lobe (Fig.4 ). Based on the macroscopic findings we diagnosed alveolar-pleural fistula, having stealthy dynamic characteristics- emissive only in specific lung lobe positions, and dorsal body recumbence not facilitating it (look at the discussion section)
Follow up and result
Immediate cease of the air accumulation was evident after the second surgery (Fig.6). Despite the fast recovery, the dog was closely monitored in clinic for 3 days, afterward the chest tube was removed and the dog discharged for home care.
The histological report that came later was suggesting not specific granulomatous lung parenchyma changes, with no causative agent (parasites/larva) present in the tested tissue.
In the presented case report multiple discussions could be initiated. They may regard the possible underlying cause of the pneumothorax, the best diagnostic tools for APF, and the best treatment – conservative vs. surgical, sternal vs. intercostal approach.
In our case we were able to confirm the mechanism of air leakage but we couldn’t reveal the exact primary cause of the lesions. Considering the anamnesis (deteriorating after ivermectin treatment) and the morphology of the lesions- small localized, discreet , we supposed parasitic) migration that had caused alveolar-visceral pleural fistulation. The adult or larva forms of some nematodes may have caused this.
There are numerous evidences that confirm that D. immitis could cause spontaneous pneumothorax (sometimes lethal) 4,5. There are case reports of a Angiostrongylus vasorum causing massive lung lesion and spontaneous pneumothorax6. Ascaris larvae invasion was reported as a cause of spontaneous pneumothorax in humans7.
Despite we suggest parasitic etiology, it is beyond our knowledge and the scope of the report to evaluate the morbidity potential of the mentioned or other (Capillaria, Oslerus) parasites. Nevertheless the cause, our retrospective interpretation of the lesions showed these: the fistula canals in the caudal part of the cranial lobe (found at first surgery) had collapsed, causing no serious air leakage, whereas the cranial fistula (found at the second surgery) was covered with epithelium, preventing it’s successful sealing and creating an air valve. It was interesting that despite its small size the APF was capable of causing serious leakage, with no tendency for healing. Indeed, the small size and the normal local serosal surface around made it difficult to distinguish during both surgeries. Another misleading factor was it’s dorsal localization. With the patient laying in dorsal recumbence, a leakage intermittently blocked by compression of the fistula against the thoracic wall was suggested by us (Fig.8-9 ). This could have been the reason for negative bubble tests- no air leakage, unless lobe manipulation and lifting it from the thoracic wall.
In the presented case, we didn’t had the chance to use advanced imaging diagnostics, so we relied on surgical exploration as diagnostic and therapeutic option, as recommended in many veterinary sources. We were able to manage the case successfully, but met some difficulties and a revision surgery was needed. It is interesting to suggest how useful could be the advanced imaging tools in the diagnose of APF. Increased accuracy (compared to chest radiography) in finding pathologic lung bullas/ blebs have been proven by studies8.9. One study comparing the accuracy of radiography and CT for bulla and bleb identification in dogs with spontaneous pneumothorax found: radiography to be accurate in 16% of cases and CT to be accurate in 80% of cases. In our case, such circumscribed , air filled structure was missing, so it is questionable if the small air leakage source (APF) could be precisely identified. Possibly, just suggestive signs of gross hypoventilation of the cranial left lung could have been found.
Our suggestion is that a bronchoscopy could also be inconclusive, dealing with a fistulation of small alveolar duct, not accessible for examination from the segmental bronchi. It is interesting if a thoracoscopy study could find such small APF. In a 2003 study,10,11 spontaneous pneumothorax, caused by bullas was successfully diagnosed and treated in three dogs using thoracoscopy,
An argument for a more consistent conservative approach- constant air evacuation system for longer period (>4 days), may be raised. Knowledge about potential causes of spontaneous pneumotorax is important factor when considering surgical versus nonsurgical management. We based our clinical decision on several reports that show the advantages of the more aggressive surgical management in canine patients . In one study, recurrence rates and mortality rates for dogs with spontaneous pneumothorax treated surgically (3% and 12%, respectively) were lower than for dogs treated conservatively (50% and 53%, respectively) 1,12.
The feline patients look more prone to conservative management (first choice treatment) of spontaneous pneumothorax, because of prevailing inflammatory ethnologies 13.
It is interesting to mention that in human patients there are publications14,15 for successfully treatment of APF by use of blood patch, synthetic hydrogel and valves, delivered endobronchialy. Watanabe spigots (IBV® valves -Olympus Corp., Japan) are specifically designed for reducing air leaks by means of total occlusion of the affected bronchus. For now, no such interventional option has been reported in the veterinary sources.
The surgical approach that we used -a median sternotomy, may be considered as more aggressive and painful than the alternative- intercostal thoracotomy. The median sternotomy is our preferred choice in such cases because it gives a vast access to all lung lobes and other thoracic structures. There are evidences that in dogs, pain, the degree of cardiopulmonary impairment, and complication rates with between two approaches do not differ 16,17, 18. In humans, median sternotomy causes less postoperative discomfort than intercostal thoracotomy19.
We recognize that a good pain control is a critical factor , when dealing with thoracotomy patients. Post operatively pain may prevent full thoracic wall excursion, reducing the ventilation and causing hypoxemia20. Pain results in catecholamine release, which contributes to vasoconstriction, decreased tissue perfusion and arrhythmias. A multimodal medical approach was used in the case providing haemodynamic stability of the patient within two open chest surgeries.
We would like to stress out the importance of following the medical algorithms in managing such spontaneous pneumothorax cases. In rare cases, the “culprit” / the underlying cause, could not be easily identified even if we know it is there. Still a persistence and systematic approach could be rewarded even in perplexed, frustrating scenarios
- Puerto DA, Brockman DJ, Lindquist C, et al: Surgical and nonsurgical management of and selected risk factors for spontaneous pneumothorax in dogs: 64 cases (1986– 1999). J Am Vet Med Assoc 220:1670, 2002.
A. MARTIN CORDERO
*VETDERM: Dermatologia Veterinaria Especializada, Guadalajara, Mexico
Assistant professor Department of Veterinary Medicine, Centro Universitario de Ciencias Biologicas y Agropecuarias, University of Guadalajara; Guadalajara, Jalisco, Mexico
A male non neutered 9 year-old Akita was presented with alopecic focal crusty lesions on rear and front limbs. Hemorrhagic lesions were observed on the front limb and history of tick infestation was provided by the owner. Ulcerative and nodular lesions were present on the right lateral aspect of the face. Skin scraping revealed presence of Demodex injai. . ELISA rapid testing IDEXX 4DX was performed to confirm tick borne disease revealing positivity to Anaplasma spp. Skin biopsies were taken from the face and abdomen revealing large atypical lymphocytes with epitheliotrophism consistent with epitheliotrophic lymphoma. The patient was presented one month later with pleural effusion, euthanasia was performed.
A male non-neutered 9 year old Akita was presented with history of focal crusty lesions. Due to his geographic origin from the North of Mexico close to the border with the United States and comments from the owner about tick infestation an ELISA SNAP 4dx plus test (Idexx) was performed.
SNAP test was positive to Anaplasma spp.
CBC showed no abnormalities.
Cutaneous lesions observed include, crusty and erythematous lesions in the abdominal regions, crusts, erosion and ulceration in the muzzle and petechial and ecchymosis in the front left limb.
A deep skin scraping was performed revealing the presence of long body Demodex compatible with Demodex injai.
Treatment with weekly Doramectin at 0.5mg/kg was started in conjunction with Doxycycline at 10mg/kg per day.
After 5 weeks of treatment owner reported depression and decrease of food ingestion, also, the appearance of new lesions in the muzzle region. Physical examination show nodular and plaque erythematous formations in the face and ventral region.
Three biopsies were taken using a 6mm punch biopsy and sent to dermatopathological examination. Results of the biopsy showed large atypical lymphocytes with epitheliotrophism consistent with epitheliotrophic lymphoma.
Demodectic mange may appear in a juvenile or adult onset presentation, as well as generalized or localized form. Patients with adult presentation should be screened in search for underlying conditions. In most cases underlying conditions will not be found. In order to control the disease, primary cause should be treated and corrected1.
Correct approach to dermatological conditions include a well-detailed clinical history and diagnostic test according to lesions found. We should be aware of perform all the diagnostic dermatological test we need, du to the fact, there are several dermatosis associated with secondary factors or associated conditions.
1.- Mueller, R. S., Bensignor, E., Ferrer, L., Holm, B., Lemarie, S., Paradis, M., & Shipstone, M. A. (2012). Treatment of demodicosis in dogs: 2011 clinical practice guidelines. Veterinary Dermatology, 23(2), 86–e21