Successful treatment of acute respiratory failure following hypertensive crisis in a dog with presumed pheochromocytoma or paraganglioma.

Background: Acute respiratory failure has been reported as one of the manifestations of hypertensive crisis in pheochromocytoma in human medicine. In dogs, no reports have been described as acute respiratory failure following hypertensive crisis. Here, we report the clinical presentation, course, and treatment of acute respiratory failure following the hypertensive crisis in a dog with presumed pheochromocytoma or paraganglioma. Case Description: A 12-year-old neutered male toy poodle was referred for the diagnostic evaluation of a right adrenal gland mass. The dog suddenly exhibited severe dyspnea with abnormal hypertension (systolic blood pressure >200 mmHg) 15 minutes after recovery from the anesthesia for the computed tomography (CT) examination. Pulmonary CT and ultrasonography findings suggested acute onset of severe pulmonary edema. Pulmonary edema was treated with mechanical ventilation (pressure-support ventilation with continuous positive airway pressure) and negative fluid balance after the administration of furosemide. Weaning from mechanical ventilation was successful 24 hours after the onset of respiratory failure. Finally, the dog was discharged 3 days after weaning from ventilation without complications. Conclusion: This report outlines a case of acute respiratory failure following a hypertensive crisis requiring mechanical ventilatory management in a dog. The onset and progression of pulmonary edema were extremely rapid. However, improvement in pulmonary edema was also rapid. Hemodynamic stability, in addition to prompt diagnosis and aggressive therapeutic intervention, including mechanical ventilation, may have contributed to the good prognosis of pulmonary edema following hypertensive crisis in a dog, which we attribute to a catecholamine storm.

Effects of 2 modes of positive pressure ventilation on respiratory mechanics and gas exchange in foals.

BACKGROUND: Continuous positive airway pressure (CPAP) and pressure support ventilation (PSV) can improve respiratory mechanics and gas exchange, but different airway pressures have not been compared in foals. HYPOTHESIS/OBJECTIVES: Assess the effect of different airway pressures during CPAP and PSV have on respiratory function in healthy foals with pharmacologically induced respiratory insufficiency. We hypothesized that increased airway pressures would improve respiratory mechanics and increased positive end-expiratory pressure (PEEP) would be associated with hypercapnia. ANIMALS: Six healthy foals from a university teaching herd. METHODS: A prospective, 2-phase, 2-treatment, randomized cross-over study design was used to evaluate sequential interventions in sedated foals using 2 protocols (CPAP and PSV). Outcome measures included arterial blood gases, spirometry, volumetric capnography, lung volume and aeration assessed using computed tomography (CT). RESULTS: Sedation and dorsal recumbency were associated with significant reductions in arterial oxygen pressure (PaO2 ), respiratory rate, and tidal volume. Continuous positive airway pressure was associated with improved PaO2 , without concurrent hypercapnia. Volumetric capnography identified improved ventilation:perfusion (V/Q) matching and increased carbon dioxide elimination during ventilation, and spirometry identified decreased respiratory rate and increased tidal volume. Peak inspiratory pressure was moderately associated with PaO2 and lung volume. Improved pulmonary aeration was evident in CT images, and lung volume was increased, particularly during CPAP. CONCLUSIONS AND CLINICAL IMPORTANCE: Both CPAP and PSV improved lung mechanics and gas exchange in healthy foals with induced respiratory insufficiency.

High-flow nasal cannula improves hypoxemia in dogs failing conventional oxygen therapy.

OBJECTIVE: A prospective clinical trial was performed to evaluate the efficacy and tolerance of high-flow nasal cannula (HFNC) in dogs with hypoxemia. ANIMALS: 20 client-owned dogs failing conventional oxygen therapy (COT). PROCEDURES: Patients admitted to the ICU for treatment of hypoxemic respiratory failure were enrolled in the study. PaO2, SPO2, respiratory rate (RR), and acute patient physiologic and laboratory evaluation scores were obtained at the time of COT failure and after initiation of HFNC. Complications and patient tolerance while receiving HFNC were also recorded. RESULTS: Compared to COT, the median PaO2 and SO2 were significantly higher when dogs were receiving HFNC (60.8 vs 135.6 mm Hg and 90.7% vs 99.25%, respectively). Dogs receiving HFNC had a significant reduction in median RR as compared to dogs undergoing COT (52 vs 36 breaths per minute). After the initiation of HFNC, all dogs showed clinical improvement as measured by PaO2, SO2, and RR. Of 20 dogs, 6 ultimately failed HFNC and mechanical ventilation was recommended. Nine dogs undergoing HFNC survived to discharge, and acute patient physiologic and laboratory evaluation scores had a significant positive severity correlation with death. Complications included pneumothorax in 1 dog. CLINICAL RELEVANCE: COT has limited flow rates due to airway irritation caused by room temperature, nonhumidified oxygen. HFNC uses vapor humidification and heated oxygen, allowing for higher flow rates. In people, HFNC is used as escalation of oxygen therapy when COT fails. Dogs treated with HFNC had significant improvements in PaO2, SO2, and RR as compared to COT. HFNC is well tolerated and effective in treating hypoxemia in dogs.

Inclusion of airway pressure release ventilation in the management of respiratory failure and refractory hypercapnia in a dog.

OBJECTIVE: To describe the use of airway pressure release ventilation (APRV) to relieve hypercapnia in a dog undergoing mechanical ventilation. CASE SUMMARY: A 3-month-old male Shar-Pei mix presented to the emergency department with suspected noncardiogenic pulmonary edema. Due to severe hypercapnia, mechanical ventilation was initiated. The hypercapnia failed to improve with conventional pressure control mechanical ventilation, bronchodilator administration, suctioning, or endotracheal tube replacement. The dog was transitioned to APRV and maintained in this mode for 36 hours. A modified APRV protocol in which inverse inspiratory to expiratory ratios ranged from 4.3:1 to 6.0:1 was utilized, resulting in a drastic improvement in the patient's hypercapnia. The patient eventually was transitioned off the ventilator, and no respiratory abnormalities have been noted at subsequent recheck examinations. NEW OR UNIQUE INFORMATION PROVIDED: This case documents the first use of APRV to relieve refractory hypercapnia in a dog undergoing mechanical ventilation and is one of the only recorded cases of using APRV for this purpose in the medical literature at large. APRV may be considered in cases of hypercapnia when traditional therapies fail, although caution is warranted as this mode of ventilation can also worsen hypercapnia.

The history and pharmacology of buprenorphine: New advances in cats.

Opiates have a long history of medical use as effective analgesics associated with well-described side effects, including euphoria, respiratory depression, constipation, bradycardia, and histamine release, among others. The search for opiate analogs that retain effective analgesic qualities without detrimental side effects has yielded numerous compounds, including buprenorphine. Early studies of buprenorphine demonstrated analgesic effectiveness with a favorable safety profile, leading to the approval of formulations for use in humans. Since then, advances in receptor theory and molecular cloning of opioid receptors have led to a deeper understanding of buprenorphine pharmacology. More recent studies of receptor affinity and intrinsic activity have shown that buprenorphine is a µ- and κ-opioid receptor agonist, a nociceptin orphanin peptide agonist, and a δ-opioid receptor antagonist. Buprenorphine appears to have a primary spinal analgesic mechanism with complex supraspinal actions. It is considered a full agonist for pain but a partial agonist for other clinical endpoints such as respiratory depression. In feline medicine, buprenorphine is approved as low- and high-concentration injectable solutions, in addition to the most recently introduced long-acting transdermal formulation. Several investigational and compounded formulations have also been evaluated. There are contrasting differentiable features that include pharmacokinetics, onsets- and durations-of-action, routes of administration, and formulation constituents. Available buprenorphine formulations allow clinicians to select a formulation based on the anticipated duration of pain associated with various surgical procedures, and to provide interventions as needed. In light of the newly approved transdermal buprenorphine solution in cats and progress in buprenorphine pharmacology, the objective of this review is to examine the history and pharmacology of buprenorphine relative to full opioid agonists, where appropriate, integrating these insights into advances within feline medicine.

Advanced Oxygen Therapy for the Small Animal Patient - High-Flow Oxygen Therapy and Mechanical Ventilation.

High-flow nasal oxygen therapy (HFNT) and positive pressure ventilation (PPV) are interventions used in the management of animals with respiratory failure. The indications for the use of these modalities, clinical application, prognosis, and a review of the current veterinary evidence are provided.

Respiratory distress in small animals: Pathophysiology and clinical approach.

BACKGROUND: Respiratory distress is a common reason for animals to present to the emergency room. An understanding of respiratory physiology is helpful to facilitate accurate localization of the patient's source of respiratory distress. This knowledge will aid implementation of more appropriate therapies. PHYSIOLOGY/PATHOPHYSIOLOGY SUMMARY: Respiratory distress can occur secondary to lesions at any location of the respiratory system. Diseases affecting different portions of the respiratory track (eg, upper airway, lower airways, parenchymal, or the pleural space) lead to distinguishing clinical signs as the patient's respiratory physiology is affected differently. CLINICAL IMPORTANCE: Respiratory distress can be life-threatening if it is not recognized and addressed in a timely matter. Prompt recognition of unique clinical signs may aid the clinician's ability to localize the disease process and implement targeted therapies. KEY POINTS: Diseases affecting different portions of the respiratory track (eg, upper airway, lower airways, parenchymal, or the pleural space) lead to distinguishing clinical signs as the patient's respiratory physiology is affected differently. Recognition of respiratory patterns allows clinicians to correlate clinical signs to the most likely affected region of the respiratory tract. Ideally, alveolar gas (ventilation) and blood flow (perfusion) are equally matched. However, even a normal lung does not have ideal ventilation/perfusion (V/Q) matching. There are a variety of conditions that lead to decreased lung compliance, from pathology of the pulmonary parenchyma (eg, pulmonary edema, alveolar infiltrates such as pneumonia or contusions, or pulmonary fibrosis), pleural space disease (eg, pneumothorax or pleural effusion), abdominal distension, or the inability to expand the rib cage (eg, pain, thoracic wall injury, constricting thoracic bandages). The five classic causes of hypoxemia include low FiO2 , diffusion impairment, hypoventilation, shunt, and V/Q mismatch. Being prepared to rapidly induce anesthesia and intubate dyspneic animals with upper airway obstruction may be required alleviate the risk of respiratory arrest.

ISOFLURANE RESPIRATORY ANESTHETIC INDEX IN CHICKENS (GALLUS GALLUS DOMESTICUS).

Respiratory depression from isoflurane seems to be greater in birds than in mammals. Isoflurane respiratory anesthetic index (AI) has only been evaluated in ducks (Anas platyrhynchos), which indeed showed a lower AI compared to mammals, but the isoflurane AI for other avian species is not known. The aim of this study was to evaluate the isoflurane AI in chickens (Gallus gallus domesticus). Six adult hens were anesthetized with isoflurane for determination of the minimum anesthetic concentration (MAC) using the bracketing method. During a second anesthetic event, the isoflurane AI was determined by progressively increasing the expired fraction of isoflurane by 0.5 times MAC until apnea was achieved (ETiso-apnea). The isoflurane AI was considered the ratio between the ETiso-apnea and the MAC. Heart rate, systolic arterial pressure, respiratory rate, and end-tidal carbon dioxide were continuously monitored throughout both anesthetic events. Data were analyzed using a mixed-effect model with Greenhouse-Geisser correction, followed by Tukey's test. The MAC for isoflurane was 1.18% ± 0.09% (mean ± SD). The ETiso-apnea was 3.31% ± 0.34% and the isoflurane AI was 2.80 ± 0.26. In chickens, isoflurane AI is similar to that measured in mammals, which is in contrast with published data in other avian species.

Reston virus causes severe respiratory disease in young domestic pigs.

Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has yet only been associated with rare asymptomatic infections in humans. Its 2008 emergence in pigs in the Philippines raised concerns about food safety, pathogenicity, and zoonotic potential, questions that are still unanswered. Until today, the virulence of RESTV for pigs has remained elusive, with unclear pathogenicity in naturally infected animals and only one experimental study demonstrating susceptibility and evidence for shedding but no disease. Here we show that combined oropharyngeal and nasal infection of young (3- to 7-wk-old) Yorkshire cross pigs with RESTV resulted in severe respiratory disease, with most animals reaching humane endpoint within a week. RESTV-infected pigs developed severe cyanosis, tachypnea, and acute interstitial pneumonia, with RESTV shedding from oronasal mucosal membranes. Our studies indicate that RESTV should be considered a livestock pathogen with zoonotic potential.

Respiratory Emergencies.

Respiratory distress is commonly seen in dogs and cats presenting to the emergency room. Rapid identification of respiratory difficulty with strategic stabilization and diagnostic efforts are warranted to maximize patient outcome. This article focuses on the relevant anatomy and physiology of the respiratory system and the clinical recognition, stabilization, and initial diagnostic planning for small animal patients that present for respiratory emergencies.

High-flow nasal cannula oxygen therapy in acute hypoxemic respiratory failure in 22 dogs requiring oxygen support escalation.

OBJECTIVE: To determine the effect of high-flow nasal cannula (HFNC) oxygen therapy on cardiorespiratory variables and outcome in dogs with acute hypoxemic respiratory failure. DESIGN: Prospective, sequential clinical trial. SETTING: University veterinary teaching hospital. ANIMALS: Twenty-two client-owned dogs that failed to respond to traditional oxygen support. INTERVENTIONS: Initiation of HFNC therapy after traditional oxygen supplementation failed to increase Spo2 > 96% and Pao2 > 75 mm Hg or improve respiratory rate/effort. MEASUREMENTS AND MAIN RESULTS: Physiological variables, blood gas analyses, and dyspnea/sedation/tolerance scores were collected prior to HFNC initiation (on traditional oxygen support [time 0 or T0]), and subsequently during HFNC oxygen administration at time 30 minutes, 60 minutes, and 7 ± 1 hours. Relative to T0, use of HFNC resulted in a decreased respiratory rate at 1 hour (P = 0.022) and 7 hours (P = 0.012), a decrease in dyspnea score at all times (P < 0.01), and an increase in Spo2 at all times (P < 0.01). There was no difference in arterial/venous Pco2 relative to T0, although Paco2 was correlated with flow rate. Based on respiratory assessment, 60% of dogs responded to HFNC use by 30 minutes, and 45% ultimately responded to HFNC use and survived. No clinical air-leak syndromes were observed. CONCLUSIONS: HFNC use improved oxygenation and work of breathing relative to traditional oxygen therapies, without impairing ventilation. HFNC use appears to be a beneficial oxygen support modality to bridge the gap between standard oxygen supplementation and mechanical ventilation.

Autopsy imaging for aspergillosis in King Penguin, an economically valuable zoo animal.

Autopsy imaging (Ai) was performed for a King Penguin. Ai-computed tomography (CT) revealed air sac membrane thickening, multiple nodules in the cranial air sac, suspected abscess, lung infiltration, and air sac contraction. Based on these findings, respiratory disorder was concerned. Aspergillosis, which is the highly observed in penguins, was considered as the primary differential diagnosis. The cultured sample showed characteristic conidial head of Aspergillus spp., the DNA of which was 100% identical to that of A. fumigatus. The cause of death was determined to respiratory failure due to aspergillosis. Ai-CT findings facilitated the dissection workflow and alerted the pathologist to potential hazards during the autopsy. Ai is useful to determine the cause of death and for readiness and safe pathological dissection.

Continuous positive airway pressure (CPAP) provision with a pediatric helmet for treatment of hypoxemic acute respiratory failure in dogs.

OBJECTIVE: To evaluate arterial blood gas parameters and pulmonary radiography, before and after provision of continuous positive airway pressure (CPAP) via a pediatric helmet in dogs with acute hypoxemic respiratory failure. DESIGN: Single-center, observational study conducted from 2016 to 2017. SETTING: University teaching hospital. ANIMALS: Seventeen dogs presenting with clinical signs compatible with respiratory failure, confirmed by arterial blood gas analyses. INTERVENTIONS: For each animal arterial blood samples and thoracic radiographs were performed at arrival (T0 ). Hypoxemic dogs (PaO2  <80 mm Hg), without evidence of pneumothorax or pleural effusion, received CPAP ventilation via a pediatric Helmet for at least 1 hour. At the end of CPAP ventilation, a second arterial blood gas analysis was performed at room air (T1 ). The F-shunt was also calculated. MEASUREMENT AND MAIN RESULTS: Respiratory rate, heart rate and rhythm, mean blood pressure, mucosal membrane color, and rectal temperature were recorded. Tolerance to the helmet was evaluated using a predetermined scoring system. Two dogs were excluded from the study for low tolerance to the helmet. In 15 of 17 dogs, a significant difference between T0 and T1 was noted for PaO2 (60.84 ± 3 mm Hg vs 80.2 ± 5.5 mm Hg), P(A-a)O2 (52.4 ± 4.4 mm Hg vs 35.2 ± 6 mm Hg), PaO2 /FiO2 (289.7 ± 14.3 vs 371 ± 21), and %SO2 (91.3 vs 98.8). In 15 of 17 dogs, the helmet was well tolerated. F-shunt significantly decreased following provision of CPAP (37%; range, 8.4-68% vs 6%; range, -5.6-64.3%). CONCLUSION: The use of a pediatric helmet appears to be a suitable device for delivery of CPAP in dogs with hypoxemic acute respiratory failure. The device appears to be reasonably tolerated and improved oxygenation in most dogs.

Retrospective evaluation of Micrurus fulvius (Eastern coral snake) envenomation and the use of mechanical ventilation in dogs and a cat (2011-2016): 8 cases.

OBJECTIVE: To describe the use of mechanical ventilation (MV) in the management of Eastern coral snake envenomation in 7 dogs and a cat. DESIGN: Retrospective study (2011-2016). SETTING: University teaching hospital. ANIMALS: Seven dogs and 1 cat receiving MV for ventilatory failure secondary to Eastern coral snake envenomation. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: The medical records of 8 animals that received MV following Eastern coral snake envenomation were reviewed. Data collected included signalment, time to veterinary assessment, physical and laboratory characteristics at arrival, clinical course during hospitalization, management including antivenom administration, MV settings, duration of ventilation, length of hospitalization, cost of care, and survival to discharge. The mean ± SD age was 4 ± 3.2 years. Median (range) time to onset of clinical signs was 30 (5-240) minutes. Coral snake antivenom was administered to 7 of the 8 animals following arrival at a median (range) of 30 (5-90) minutes. All animals had progressive hypoventilation and received MV, specifically volume controlled, synchronized intermittent mandatory ventilation with pressure support. The median (range) duration of MV was 58 (25-84) hours and the median (range) duration of hospitalization was 8.2 (6-11) days. Ventilator associated complications occurred in all animals, but overall outcome was excellent with 7 of 8 surviving to discharge. No dog, but the 1 cat, had an adverse reaction to antivenom. CONCLUSIONS: Ventilatory failure secondary to Eastern coral snake envenomation necessitating MV carries an excellent prognosis and is better than reported for other causes of lower motor neuron disease. Successful response to ventilation was achieved even with associated complications being common in this cohort of animals.

Dose-effect study of the serotonin agonist R-8-OH-DPAT on opioid-induced respiratory depression in blesbok (Damaliscus pygargus philipsi) and impala (Aepyceros melampus).

OBJECTIVE: To determine whether the R-enantiomer of 8-hydroxy-2-(di-n-propylamino) tetralin (R-8-OH-DPAT) alleviates respiratory depression in antelope species immobilized with etorphine. The experiment also aimed to establish the most clinically effective dose of this serotonin 5- HT1A receptor agonist. ANIMALS: A group of six female blesbok and six female impala. STUDY DESIGN: Each animal was subjected to four immobilization treatments in a prospective four-way crossover design-control treatment consisting of only etorphine at 0.09 mg kg-1 and three treatments consisting of etorphine at 0.09 mg kg-1 combined with 0.005, 0.02 and 0.07 mg kg-1 of R-8-OH-DPAT, respectively. Induction, quality of immobilization and recovery were monitored in each treatment. Physiological variables including heart rate, respiratory rate, arterial blood pressure and blood gases were measured for 35 minutes during immobilization. A linear mixed model was used to assess the effects of treatments over the recumbency period. RESULTS: R-8-OH-DPAT did not influence induction, immobilization or recovery scores. Respiratory rate in blesbok was increased in the medium- and high-dosage R-8-OH-DPAT treatment group. However, this increased respiratory rate did not translate into improvements of arterial partial pressure of oxygen (PaO2) values in the blesbok. The medium and higher dosages of R-8-OH-DPAT in impala led to an improved PaO2 as well as to decreased opioid-induced tachycardia during the first 10 minutes of immobilization. CONCLUSIONS AND CLINICAL RELEVANCE: Previous reports indicated that the racemic mixture of 8-OH-DPAT injected intravenously had a positive effect on blood-gas values in etorphine-treated hypoxemic goats. In this experiment, similar effects could be seen in impala at the higher dosage rates of R-8-OH-DPAT. However, failure to achieve an improvement of blood-gas values in blesbok was an unexpected result. It could be speculated that the dosage, species-specific differences of serotonin receptors or the use of the R-enantiomer of 8-OH-DPAT might play a role.

Clinical manifestations, laboratory findings, treatment and outcome of acute organophosphate or carbamate intoxication in 102 dogs: A retrospective study.

Organophosphates (OP) and carbamates are commonly used insecticides and important intoxication sources of humans and animals. Nevertheless, large scale studies of these intoxications in dogs are unavailable. The medical records of dogs presented to a veterinary hospital were reviewed retrospectively. The study included 102 dogs definitely diagnosed with acute OP or carbamate intoxication. The most common presenting clinical signs included muscle tremor, hypersalivation, miosis, weakness, vomiting and diarrhea. Hypersalivation, muscle tremor and tachypnea were significantly (P < 0.05) associated with survival to discharge; while weakness, mental dullness, anorexia, pale mucous membranes and paddling were significantly associated with death. Common laboratory abnormalities included decreased butyrylcholine esterase activity, acidemia, increased total plasma protein, leukocytosis, hypochloridemia, hyperbilirubinemia, increased creatinine and alanine transaminase (ALT), aspartate transaminase (AST) and creatine kinase activities, and prolonged activated partial thromboplastin time (aPTT). Compared to the survivors, the non-survivors showed significantly: higher frequencies of thrombocytopenia, hypocarbemia, prolonged prothrombin time (PT), hypernatremia, hyperkalemia, hypocholesterolemia, hypoproteinemia, hypertriglyceridemia, increased ALT activity and increased urea concentration; lower median concentrations of venous blood bicarbonate, serum chloride and total CO2; and higher medians of PT, serum total bilirubin and urea concentrations, and ALT and AST activities. Intoxicated dogs were commonly treated with diphenhydramine, atropine-sulfate, antibiotics, diazepam and pralidoxime, while some (19.2%) required general anesthesia and mechanical ventilation. The survival rate of dogs treated by gastric lavage was higher (P = 0.041) compared to that of the remaining dogs. Development of respiratory failure and mechanical ventilation requirement were significantly associated (P < 0.001) with death. The mortality rate was 17%.

Effects of continuous positive airway pressure on respiratory function in sedated foals.

OBJECTIVE: To characterize the effects of continuous positive airway pressure (CPAP) delivered by a commercial human CPAP device on respiratory function in foals with pharmacologically induced respiratory suppression. DESIGN: Prospective randomized, cross-over study comparing CPAP with spontaneous respiration and oxygen insufflation. SETTING: University veterinary teaching hospital. ANIMALS: Twelve foals born in consecutive seasons from a university teaching herd. INTERVENTIONS: Foals were randomized to receive 10 minutes of respiratory support by mask oxygen supplementation or CPAP as a first treatment after induction of respiratory depression by intravenous administration of xylazine and fentanyl. Each foal received the alternate treatment after 10 minutes of breathing ambient air, and the procedure was repeated after 48 hours with treatment order reversed. MEASUREMENTS AND MAIN RESULTS: The administration of xylazine and fentanyl by bolus or continuous infusion reliably induced reversible respiratory suppression and recumbency. CPAP was associated with comparable increase in PaO2 relative to mask oxygen supplementation, but with lower respiratory rate, increased oxygen extraction and increased carbon dioxide elimination. Mild increase in PaCO2 was observed during CPAP and O2 supplementation. Expiratory time increased and peak expiratory flow decreased during CPAP. CONCLUSIONS: Findings of the study suggest that CPAP might represent a method for improved respiratory support compared to O2 insufflation due to increased respiratory efficiency. Care must be taken in extrapolation of these findings from foals with pharmacologically induced respiratory compromise to foals with clinical respiratory disease, and further investigation is required to better characterize the cause and impact of marginal hypercapnia observed in these studies.

Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum).

Opioid-induced immobilisation results in severe respiratory impairment in the white rhinoceros. It has therefore been attempted in the field to reverse this impairment with the use of opioid agonist-antagonists, such as nalorphine, nalbuphine, butorphanol and diprenorphine; however, the efficacy of some of these treatments has yet to be determined. The efficacy of butorphanol, either alone or in combination with diprenorphine both with and without oxygen insufflation, in alleviating opioid-induced respiratory impairment was evaluated. The study was performed in two parts: a boma trial and a field trial. Rhinoceroses were immobilised specifically for the study, according to a strict protocol to minimise confounding variables. A two-way analysis of variance was used to compare the physiological responses of the rhinoceroses to the different treatments and their effects over time. The intravenous administration of butorphanol (at 3.3 mg per mg etorphine) plus diprenorphine (at 0.4 mg per mg etorphine) did not offer any advantage over butorphanol (at 15 mg per mg etorphine) alone with regard to improving PaO2, PaCO2 and respiratory rates in etorphine-immobilised white rhinoceroses. Both butorphanol + diprenorphine + oxygen and butorphanol + oxygen, at the doses used, significantly improved the etorphine-induced hypoxaemia in both boma- and field-immobilised white rhinoceroses. Clinically acceptable oxygenation in field-immobilised white rhinoceroses can be achieved by using either treatment regimen, provided that it is combined with oxygen insufflation.

Anticoagulant rodenticide toxicosis causing tracheal collapse in 4 small breed dogs.

OBJECTIVE: To describe 4 cases of tracheal narrowing attributed to tracheal mucosal hemorrhage caused by anticoagulant rodenticide toxicity in breeds predisposed to tracheal collapse. CASE SUMMARY: Over the years 2005-2014, 4 dogs were presented for respiratory distress secondary to diffuse tracheal narrowing. All dogs had possible anticoagulant rodenticide ingestion and prolonged prothrombin time. All dogs received fresh-frozen plasma transfusions, vitamin K1 supplementation, and supportive care. Tracheal narrowing improved on follow-up radiographs in 3 of 4 patients. One of 4 did not have follow-up radiographs performed. All dogs survived. NEW OR UNIQUE INFORMATION PROVIDED: Anticoagulant rodenticide toxicity causing clinical signs consistent with tracheal collapse is a rare but recognized phenomenon that has not been previously reported in breeds prone to tracheal collapse.

Pathology and causes of death in stranded humpback whales (Megaptera novaeangliae) from Brazil.

This study describes the pathologic findings of 24 humpback whales (Megaptera novaeangliae) found stranded along the Brazilian coast from 2004 to 2016. Eighteen (75%) animals evaluated were found stranded alive. From these, 13 died naturally on shore and five were euthanized. Six died at sea and were washed ashore. Of the 24, 19 (79.2%) were calves, four (16.7%) were juveniles, and one (4.2%) was an adult. The most probable cause of stranding and/or death (CSD) was determined in 23/24 (95.8%) individuals. In calves, CSD included neonatal respiratory distress (13/19; 68.4%), infectious disease (septicemia, omphaloarteritis and urachocystitis; 3/19; 15.8%), trauma of unknown origin (2/19; 10.5%), and vehicular trauma (vessel strike; 1/19; 5.3%). In juveniles and adult individuals, CSD was: emaciation (2/5; 40%), sunlight-thermal burn shock (1/5; 20%); and discospondylitis (1/5; 20%). In one juvenile, the CSD was undetermined (1/5; 20%). This study integrates novel findings and published case reports to delineate the pathology of a South-western Atlantic population of humpback whales. This foundation will aid in the assessment of the population health and establish a baseline for development of conservation policies.