Postprandial effects following a semielemental critical-care diet lead to changes in uric acid, bile acids, and glucose in the central bearded dragon (Pogona vitticeps).

OBJECTIVE: To assess the prandial effects of a semielemental diet on plasma uric acid, bile acid, and glucose concentrations in the central bearded dragon (Pogona vitticeps). ANIMALS: 13 healthy adult male bearded dragons. METHODS: Following a 72-hour fasting period, blood was collected to measure preprandial uric acid, bile acid, and glucose concentrations. The animals were then gavage fed 1.2% body weight of an omnivore critical-care diet containing 20% protein, 9.5% fat, 2.5% fiber, and 2.39 kcal/mL. Blood was collected for repeat concentrations at 4 and 24 hours. RESULTS: Median (IQR) uric acid concentration (mg/dL) increased from 3.8 preprandial (2.8 to 4.3) to 4.7 4 hours postprandial (4 to 7; P = .0001). Median (IQR) bile acid concentration (mg/dL) increased from 1.8 preprandial (1 to 3.4) to 9.5 24 hours postprandial (5.6 to 10.4; P = .004). Median (IQR) glucose concentration (mg/dL) was 209 at time 0 (193 to 216), 287 at 4 hours (258 to 312), and 393 at 24 hours (361 to 464). Significant increases were seen between pre- and 4-hours-postprandial (P < .0001), pre- and 24-hours-postprandial (P < .0001), and 4-hours- and 24-hours-postprandial (P < .0001) glucose concentrations. CLINICAL RELEVANCE: Results suggest that postprandial status and diet composition should be considered during the interpretation of some biochemical analytes in the bearded dragon.

Chronic mandibular osteomyelitis associated with a novel probable Kocuria sp in a sugar glider (Petaurus breviceps).

Dental disease in sugar gliders (Petaurus breviceps) is understudied, with only limited clinical and pathological data available. An approximately 7-year-old female sugar glider presented to its primary care veterinarian for a decline in food intake, rapid weight loss and a mass involving the rostral mandible. At necropsy, the mandibular mass effaced most of the rostral mandible and adjacent musculature. Histologically, the mandible was disrupted by nodular infiltrates of variably degenerate neutrophils and macrophages encased in granulomatous inflammation and fibrous connective tissue. Within the neutrophilic cell population were segments of fragmented, necrotic bone and cloud-like colonies of gram-positive cocci. Aerobic culture yielded a heavy, pure growth of a gram-positive coccus morphologically consistent with those identified in the lesions, which was identified as a presumptively novel Kocuria sp by polymerase chain reaction and sequencing of the 16S rRNA gene. This is the first description of Kocuria infection in association with clinically significant pathology in an animal. Although isolated as a pure growth, Kocuria sp cannot be confirmed as the sole cause of lesion formation due to the case chronicity and potential for unculturable, polymicrobial infections. This report adds to our understanding of the clinical and pathological aspects of dental disease in sugar gliders.

Testosterone identifies hatchling sex for Mojave desert tortoises (Gopherus agassizii).

The threatened Mojave desert tortoise (Gopherus agassizii) exhibits temperature-dependent sex determination, and individuals appear externally sexually monomorphic until sexual maturity. A non-surgical sex identification method that is suitable for a single in situ encounter with hatchlings is essential for minimizing handling of wild animals. We tested (1) whether plasma testosterone quantified by enzyme-linked immunosorbent assay differentiated males from females in 0-3 month old captive hatchlings, and (2) whether an injection of follicle-stimulating hormone (FSH) differentially elevates testosterone in male hatchlings to aid in identifying sex. We validated sex by ceolioscopic (laparoscopic) surgery. We then fit the testosterone concentrations to lognormal distributions and identified the concentration below which individuals are more likely female, and above which individuals are more likely male. Using a parametric bootstrapping procedure, we estimated a 0.01-0.04% misidentification rate for naïve testosterone samples, and a 1.26-1.39% misidentification rate for challenged (post-FSH injection) testosterone samples. Quantification of plasma testosterone concentration from small volume (0.1 mL) blood samples appears to be a viable, highly accurate method to identify sex of 0-3 month old hatchlings and could be a valuable tool for conservation measures and investigation of trends and variation in sex ratios for in situ wild nests.

Retrospective assessment of general anesthesia-related challenges, morbidity, and death in snakes: 139 cases (2000-2022).

OBJECTIVE: To summarize the anesthetic events of snakes seen at a large university hospital, identify challenges with record keeping, and assess patient and anesthesia-related morbidity and death. SAMPLE: 139 anesthetic events were performed; only 106 cases had detailed anesthetic reports available for further analyses. PROCEDURES: Medical records of snakes that underwent general anesthesia between October 2000 and January 2022 were retrospectively reviewed. Only cases with complete anesthesia records were used to assess anesthetic parameters. Collected data included general patient details, diagnoses, procedures, premedication, induction, maintenance, monitoring, and recovery. RESULTS: A thorough review of the records identified issues or scenarios that resulted in poor record management as well as highlighted the most frequently used anesthetics in snakes. For premedication this was alfaxalone, butorphanol, and hydromorphone, whereas isoflurane, alfaxalone, or propofol were the most common with induction. Lastly, with maintenance, isoflurane was the most popular choice. Of the 139 cases performed, 127 animals recovered, 8 were euthanatized due to poor prognosis, and 4 failed to recover. All snakes that failed to recover had preexisting disease identified pre-, peri-, or postoperatively at necropsy. CLINICAL RELEVANCE: General anesthesia can be reliably and safely undertaken in snakes without severe preexisting disease. Efforts should be directed at identifying preexisting disease and maintaining and completing anesthesia records, and we recommend an auditing system to identify and correct issues as they arise.

MRI of the live fish brain at 3 Tesla: Feasibility, technique and interspecies anatomic variations.

Advances in aquatic animal medicine and continued growth of the fish hobbyist and aquaculture communities have led to a developing interest in antemortem diagnostic imaging of aquatic species. The aims of this prospective, pilot study were to determine whether advanced neuroimaging can be safely achieved in live fish using clinically available equipment, to optimize imaging parameters, and to develop a comparative MRI atlas of a few fish species of economic or research value. Two each of channel catfish (Ictalurus punctatus), koi (Cyprinus rubrofuscus), and grass carp (Ctenopharyngodon idella) of at least 30 cm in length were individually anesthetized for 3 Tesla (3T) magnetic resonance imaging (MRI) of the brain. All fish achieved an adequate anesthetic level for prolonged immobilization during imaging. Diagnostic quality images were obtained for all subjects; however, the spatial resolution was maximized with larger fish. Imaging protocols were optimized for standard neuroimaging sequences. Additionally, inversion times for fluid-attenuation inversion recovery (FLAIR) sequences were adapted to the naturally high protein content of fish pericerebral fluid. Following imaging, the fish successfully recovered from anesthesia, were humanely euthanized, and were immediately processed to assess brain histopathology. Necropsy confirmed the sex and health status of each fish. A limited comparative MRI atlas was created of the brains of these species for clinical reference. Findings from the current study supported the use of 3T MRI as an adjunct diagnostic test for fish with suspected neurologic disease and provided a limited anatomic atlas of the teleost brain for use as a reference.

Use of computed tomography and magnetic resonance imaging to assess a case of spinal injury in a Showa koi Cyprinus carpio.

OBJECTIVE: A privately owned, 4-year-old female Showa koi (ornamental variant of Common Carp Cyprinus carpio) was presented for erratic swimming, air gasping, water spitting, and abnormal orientation in the water column. Initial physical examination revealed an obese patient with no external abnormalities except a small plaque localized to filaments on a right gill hemibranch. METHODS: The fish was anesthetized using AQUI-S 20E (10% eugenol solution) at 50 mg/L to facilitate diagnostic evaluation. Biopsy of the gill lesion yielded no significant findings. Whole-body computed tomography confirmed an excess of adipose tissue and mild scoliosis, with narrowing of the 10th-11th intervertebral space. A weight loss plan and need for repeat assessment were recommended. RESULT: The patient's original abnormal behaviors resolved over the following weeks, but it subsequently became hyporexic and depressed. Full-body magnetic resonance imaging (MRI) showed extensive alteration of vertebral centra, with multifocal compression of the spinal cord. Due to the patient's declining clinical condition and the grave prognosis based on MRI findings, the patient was humanely euthanized. CONCLUSION: Postmortem examination showed severe transmural myelomalacia associated with a vertebral subluxation. This case demonstrates the practical application of advanced cross-sectional imaging that has not been commonly afforded to fish or other lower vertebrates.

Endoscopic sexing in turtles and tortoises: 467 cases (2007-2017).

BACKGROUND: This multi-institutional retrospective study evaluated the feasibility and safety of endoscopic sex identification in 467 turtles and tortoises, representing 10 species. METHODS: Medical records of turtles and tortoises that underwent endoscopic sex identification at the University of Georgia, New England Aquarium and Turtle Conservancy were reviewed for presurgical management, anaesthesia, endoscopic equipment and surgical techniques, endoscopic results and complications. RESULTS: The majority of animals weighed less than 200 g, were fasted and anaesthetised using an injectable combination of ketamine, dexmedetomidine and morphine or hydromorphone, supplemented by local lidocaine at the prefemoral site. Anaesthetic reversal using atipamezole alone or in combination with naloxone was routine. For uncomplicated procedures, mean total anaesthesia, surgery and recovery times were 22, 4 and 18 minutes, respectively. All animals were placed in lateral recumbency for a prefemoral endoscopic approach to the coelom using a rigid telescope and sterile fluid infusion to visualise the gonads. Sex identification was definitive in 99.4% (n = 464) of the animals. Iatrogenic bladder perforation was the most common complication (n = 5), which necessitated extended anaesthesia and surgical time for repair. Only a single anaesthetic-related death was reported, which was associated with human error and drug overdose. CONCLUSIONS: This is the first large-scale study to retrospectively evaluate endoscopic sex identification in multiple chelonian species. Results suggest that endoscopic sexing is a safe, accurate and practical means for sex identification in turtles and tortoises, and represents a valuable tool in their reproductive management.

Coagulation testing in green iguanas (Iguana iguana) with development of prothrombin time assays using reptile and avian thromboplastin.

BACKGROUND: Captive reptiles often present with clinical signs suggestive of a clotting disorder or severe illness that can induce or exacerbate a coagulopathy. However, coagulopathies in reptiles are difficult to characterize due to lack of species-appropriate reagents to perform coagulation tests. The objective of this study was to develop screening tests to evaluate the extrinsic and common pathways of coagulation in green iguanas (Iguana iguana). KEY FINDINGS: Reptile and avian thromboplastin, extracted from reptile and avian brains, respectively, were used to initiate coagulation in prothrombin time (PT) assays and commercially available reagents were used to determine Russell's viper venom time, thrombin time, and fibrinogen using the Clauss method. Coagulation assays were performed on citrate-anticoagulated plasma from 18 healthy green iguanas. Results were summarized as median (minimum-maximum): PT (reptile thromboplastin), 34.8 seconds (27.1-42.1 s), PT (avian thromboplastin), 78.5 seconds (51.6-114.23 s), Russell's viper venom time, 56.15 seconds (18.4-79.7 s), thrombin time, 10 seconds (7.0-36.5 s), and fibrinogen, 258 mg/dl (89-563.0) (2.58 [0.89-5.63 g/L]). SIGNIFICANCE: Commercial reagents can be used to evaluate the common pathway and fibrinogen; however, avian- or reptile-sourced thromboplastin is preferred for a reliable coagulation trigger to perform the PT assay and evaluate the extrinsic pathway.

Respiratory Diseases of Snakes.

Respiratory abnormalities in snakes are a common clinical presentation in zoologic medical practice. There are often compounding issues involving translocation and substandard husbandry that can predispose to infectious and noninfectious causes of respiratory disease. Endoscopic evaluation of the respiratory tract and the collection of biopsies for histopathology and microbiology is preferred but may only be available from the specialist. Alternatively, transtracheal lavage for cytology and microbiology is a practical method for most practitioners. A variety of bacterial, fungal, viral, and parasitic infections, as well as noninfectious diseases have been reported. Accurate diagnosis dictates specific therapy, which increases the likelihood of successful treatment.

Antimicrobial susceptibility patterns for aerobic bacteria isolated from reptilian samples submitted to a veterinary diagnostic laboratory: 129 cases (2005-2016).

OBJECTIVE: To identify antimicrobial susceptibility patterns for aerobic bacteria isolated from reptilian samples and, from those patterns, identify antimicrobials that could be considered for empirical treatment of reptiles with suspected bacterial infections. SAMPLES: 129 bacterial isolates from 61 of 127 samples from 96 reptiles. PROCEDURES: Medical records of reptiles (chelonian, crocodilian, lizard, and snake) presented to the zoological medical service of a veterinary teaching hospital between January 2005 and December 2016 were reviewed for submissions of patient samples for aerobic bacterial culture and susceptibility testing. Sample type, presence or absence of bacterial growth, and antimicrobial susceptibilities of isolated bacteria were recorded. The isolation frequency and the antimicrobial susceptibilities of bacterial genera and species were tabulated. RESULTS: Pseudomonas spp and Enterococcus spp were the most frequently isolated gram-negative and gram-positive bacteria, respectively. Isolates of gram-negative bacteria frequently had susceptibility to amikacin (86%), gentamicin (95%), tobramycin (92%), and trimethoprim-sulfamethoxazole (83%), and gram-positive bacteria frequently had susceptibility to ampicillin (83%), chloramphenicol (92%), doxycycline (100%), and gentamicin (100%). Isolates of gram-positive bacteria were consistently resistant to ceftazidime. CONCLUSIONS AND CLINICAL RELEVANCE: Aerobic bacterial culture and antimicrobial susceptibility results for reptilian samples in this population indicated that aminoglycosides and trimethoprim-sulfamethoxazole or ampicillin and doxycycline could be considered as options for the empirical treatment of reptiles with infections caused by gram-negative or gram-positive bacteria, respectively.

Comparison of endoscopic endotracheal intubation and the v-gel supraglottic airway device for spontaneously ventilating New Zealand white rabbits undergoing ovariohysterectomy.

BACKGROUND: Due to the technical difficulties with endotracheal intubation of rabbits, a prospective, randomised, controlled study was performed to compare a rabbit-specific supraglottic airway device (SGAD), the v-gel, with endoscopic endotracheal intubation (EEI) in spontaneously breathing rabbits undergoing ovariohysterectomy. METHODS: Fourteen adult female New Zealand white rabbits were randomly allocated to one of two groups based on the method of airway establishment: EEI or v-gel SGAD. Anaesthesia was induced with ketamine and xylazine and maintained using isoflurane in 100 per cent oxygen. Comparisons were made between groups based on placement time of endotracheal tube/SGAD, number of attempts and adjustments, the necessity to increase isoflurane concentrations to maintain a surgical plane of anaesthesia, arterial blood gas values, gross laryngeal evaluation, and laryngotracheal histopathology. RESULTS: Both techniques resulted in elevated arterial pCO2 levels, but the v-gel was associated with more elevated pCO2 in comparison with EEI (P=0.045). Airway trauma was histologically present but clinically negligible in both groups, with no statistically significant differences observed between techniques (P>0.05). Placement time of the v-gel was significantly faster (P=0.003) and required less technical skill than EEI, but was more easily displaced when changing the animal's position (P=0.004). CONCLUSION: The v-gel is a practical alternative to EEI for securing the airway of healthy spontaneously ventilating rabbits, provided a capnograph is utilised to ensure continuous placement. Both airway techniques appear safe and effective with few complications, as long as intermittent positive pressure ventilation can be employed to correct hypercapnia.

Computed tomographic and ultrasonographic diagnosis with successful excision of a lipoma in a shusui koi (Cyprinus carpio).

CASE DESCRIPTION: A client-owned 12-year-old 10.3-kg (22.7-lb) female shusui koi (Cyprinus carpio) was evaluated because of an ulcerated mass on the left body wall, hyporexia, and decreased activity. CLINICAL FINDINGS: The patient was anesthetized with a solution of eugenol in water for all examinations and procedures. An approximately 7 × 5-cm smooth, raised, ulcerated, and firm mass was present ventral and lateral to the dorsal fin on the left body wall. Whole-body CT images obtained before and after contrast administration revealed an encapsulated, homogeneous, fat-opaque mass within the muscle. The mass was fat echoic with poor vascularity on ultrasonographic examination. Histologic evaluation of an ultrasound-guided needle biopsy specimen was suggestive of a lipoma. TREATMENT AND OUTCOME: The mass was excised, and the fish was placed in water with 0.3% salinity for 3 weeks after surgery. Postoperative antimicrobial administration was not indicated, and additional postoperative analgesic administration was considered impractical. The patient had noticeable improvement in appetite and activity with no indication of discomfort immediately following surgery. Five weeks after surgery, the incision site had healed with minimal scarring, and evaluation of CT images revealed no evidence of mass regrowth or regional osteomyelitis. CLINICAL RELEVANCE: Antemortem evaluation and diagnosis of a lipoma in a teleost with subsequent excision was described. This report highlighted the logistic challenges associated with anesthesia, advanced diagnostic imaging, and surgery in fish and showed that they can be successfully overcome so that high-level medical care can be provided to such patients.

A systematic study of injectable anesthetic agents in the brown anole lizard (Anolis sagrei ).

Anolis lizards have served as important research models in fields ranging from evolution and ecology to physiology and biomechanics. However, anoles are also emerging as important models for studies of embryo development and tissue regeneration. The increased use of anoles in the laboratory has produced a need to establish effective methods of anesthesia, both for routine veterinary procedures and for research procedures. Therefore, we tested the efficacy of different anesthetic treatments in adult female Anolis sagrei. Alfaxalone, dexmedetomidine, hydromorphone, ketamine and tribromoethanol were administered subcutaneously (SC), either alone or combined at varying doses in a total of 64 female anoles. Drug induction time, duration, anesthesia level and adverse effects were assessed. Differences in anesthesia level were observed depending on injection site and drug combination. Alfaxalone/dexmedetomidine and tribromoethanol/dexmedetomidine were the most effective drug combinations for inducing a surgical plane of anesthesia in anoles. Brown anoles injected SC with alfaxalone (30 mg/kg) plus dexmedetomidine (0.1 mg/kg) or with tribromoethanol (400 mg/kg) plus dexmedetomidine (0.1 mg/kg) experienced mean durations of surgical anesthesia levels of 31.2 ± 5.3 and 87.5 ± 19.8 min with full recovery after another 10.9 ± 2.9 and 46.2 ± 41.8 min, respectively. Hydromorphone given with alfaxalone/dexmedetomidine resulted in deep anesthesia with respiratory depression, while ketamine/hydromorphone/dexmedetomidine produced only light to moderate sedation. We determined that alfaxalone/dexmedetomidine or tribromoethanol/dexmedetomidine combinations were sufficient to maintain a lizard under general anesthesia for coeliotomy. This study represents a significant step towards understanding the effects of anesthetic agents in anole lizards and will benefit both veterinary care and research on these animals.

Clinical Management of Reptile Renal Disease.

Renal disease is one of the most common medical conditions encountered in captive reptiles. In most cases, signs of disease are nonspecific and often not present until the condition is advanced. Many factors contribute to the development of renal disease, and the etiology often is multifactorial. Diagnosis of renal disease by traditional methods used in small animals is not as straightforward as in reptiles; often many tests may be needed to reach a firm diagnosis. Prevention is preferred to treatment. Understanding the pathophysiology, potential causes, diagnostic tests available, and treatment options is essential for the reptile veterinarian to manage this condition.

Diagnostic value of plasma biochemistry, haematology, radiography and endoscopic visualisation for hepatic disease in psittacine birds.

BACKGROUND: Hepatic disease in psittacine birds is common but challenging to diagnose. This retrospective study evaluates the diagnostic value of plasma biochemistry, haematology, radiography and endoscopic visualisation in psittaciforms with suspected hepatic disease that underwent endoscopic liver biopsy. METHODS: Clinical records of 28 companion psittaciforms from a veterinary teaching hospital (2007-2016) were reviewed. Diagnostic results were categorised as abnormal or normal and compared with histopathology for agreement or disagreement. Statistical significance was determined by kappa test for agreement and McNemar's test for disagreement. RESULTS: 11 of 28 psittaciforms (39.3 per cent) had clinical signs considered specific for liver disease. 25 of 28 (89.3 per cent) psittaciforms had histopathological liver lesions. Gross changes radiographically and endoscopically agreed with histopathology in 57.1 per cent and 53.6 per cent of cases, respectively. Aspartate aminotransferase (AST) (48.1 per cent), creatine phosphokinase (73.1 per cent) and albumin by protein electrophoresis (50 per cent) showed the highest agreement. Kappa was not significant for any parameters, while McNemar's test for disagreement was significant for radiography, endoscopy, AST, lactate dehydrogenase, bile acid, total protein (chemistry), cholesterol, triglycerides, uric acid and glucose. CONCLUSION: Overall, changes on plasma biochemistry, radiography or endoscopy are non-specific and do not consistently agree with histopathology results. Endoscopic liver biopsy is highly recommended if there is clinical suspicion of hepatic disease.

Technological Advances in Endoscopic Equipment in Exotic Pet Medicine.

The aim of this article is to review some of the technological advances in endoscopy and endosurgery. The article focuses on a few key areas relevant to exotic pets, including advances in urolith management, visualization, and laparoscopic surgery.

Gross and histologic evaluation of effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product on experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana).

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). ANIMALS 16 healthy subadult green iguanas. PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm2 or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity. RESULTS On day 14, wounds treated with a laser at 10 J/cm2 were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments. CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm2 appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

Effects of intravenous administration of lidocaine and buprenorphine on gastrointestinal tract motility and signs of pain in New Zealand White rabbits after ovariohysterectomy.

OBJECTIVE To compare analgesic and gastrointestinal effects of lidocaine and buprenorphine administered to rabbits undergoing ovariohysterectomy. ANIMALS Fourteen 12-month-old female New Zealand White rabbits. PROCEDURES Rabbits were assigned to 2 treatment groups (7 rabbits/group). One group received buprenorphine (0.06 mg/kg, IV, q 8 h for 2 days), and the other received lidocaine (continuous rate infusion [CRI] at 100 µg/kg/min for 2 days). Variables, including food and water consumption, fecal output, glucose and cortisol concentrations, and behaviors while in exercise pens, were recorded. RESULTS Rabbits receiving a lidocaine CRI had significantly higher gastrointestinal motility, food intake, and fecal output and significantly lower glucose concentrations, compared with results for rabbits receiving buprenorphine. Rabbits receiving lidocaine also had a higher number of normal behaviors (eg, sprawling, traveling, and frolicking) after surgery, compared with behaviors such as crouching and sitting that were seen more commonly in rabbits receiving buprenorphine. Both groups had significant weight loss after surgery. Pain scores did not differ significantly between treatment groups. Significant decreases in heart rate and respiratory rate were observed on the day of surgery, compared with values before and after surgery. Rabbits in the lidocaine group had significantly overall lower heart rates than did rabbits in the buprenorphine group. CONCLUSIONS AND CLINICAL RELEVANCE A CRI of lidocaine to rabbits provided better postoperative outcomes with respect to fecal output, food intake, and glucose concentrations. Thus, lidocaine appeared to be a suitable alternative to buprenorphine for alleviating postoperative pain with minimal risk of anorexia and gastrointestinal ileus.

Outcome following inhalation anesthesia in birds at a veterinary referral hospital: 352 cases (2004-2014).

OBJECTIVE To determine the outcome in birds undergoing inhalation anesthesia and identify patient or procedure variables associated with an increased likelihood of anesthesia-related death. DESIGN Retrospective case series. ANIMALS 352 birds that underwent inhalation anesthesia. PROCEDURES Medical records of birds that underwent inhalation anesthesia from January 1, 2004, through December 31, 2014, at a single veterinary referral hospital were reviewed. Data collected included date of visit, age, species, sex, type (pet, free ranging, or wild kept in captivity), body weight, body condition score, diagnosis, procedure, American Society of Anesthesiologists status, premedication used for anesthesia, drug for anesthetic induction, type of maintenance anesthesia, route and type of fluid administration, volumes of crystalloid and colloid fluids administered, intraoperative events, estimated blood loss, duration of anesthesia, surgery duration, recovery time, recovery notes, whether birds survived to hospital discharge, time of death, total cost of hospitalization, cost of anesthesia, and nadir and peak values for heart rate, end-tidal partial pressure of carbon dioxide, concentration of inhaled anesthetic, and body temperature. Comparisons were made between birds that did and did not survive to hospital discharge. RESULTS Of 352 birds, 303 (86%) were alive at hospital discharge, 12 (3.4%) died during anesthesia, 15 (4.3%) died in the intensive care unit after anesthesia, and 22 (6.3%) were euthanatized after anesthesia. Overall, none of the variables studied were associated with survival to hospital discharge versus not surviving to hospital discharge. CONCLUSIONS AND CLINICAL RELEVANCE Results confirmed previous findings that indicated birds have a high mortality rate during and after anesthesia, compared with mortality rates published for dogs and cats.