Perianesthetic morbidity and mortality in dogs undergoing cervical and thoracolumbar spinal surgery.

OBJECTIVE: To evaluate and compare perioperative morbidity and mortality in dogs undergoing cervical and thoracolumbar spinal surgery. STUDY DESIGN: Prospective case series. ANIMALS: 157 dogs undergoing cervical or thoracolumbar spinal surgery. METHODS: Data were collected sequentially on canine cases presented from the Neurology Section of the North Carolina State University Veterinary Teaching Hospital for anesthesia and surgery for cervical spinal cord disease. Simultaneously, data were collected on all thoracolumbar spinal surgery cases during the same time period. Data included signalment, drugs administered, surgical approach, disease process, cardiac arrhythmias during anesthesia, and outcome. RESULTS: Data were collected from 164 surgical events in 157 dogs. There were 52 cervical approaches; four dorsal and 48 ventral. All thoracolumbar surgeries were approached dorsolaterally. Four dogs 4/52 (7.6%) undergoing a cervical approach did not survive to discharge. Two dogs (2/8; 25%) underwent atlanto-axial (AA) stabilization and suffered cardiovascular arrest and two dogs (2/38; 5.2%) undergoing cervical ventral slot procedures were euthanized following anesthesia and surgery due to signs of aspiration pneumonia. All dogs undergoing thoracolumbar surgery survived until discharge (112/112). Mortality in dogs undergoing cervical spinal surgery was greater compared with dogs undergoing thoracolumbar spinal surgery (p = 0.009), however, in dogs undergoing decompressive disc surgery, intraoperative death rates were not different between dogs undergoing a cervical compared with thoracolumbar approaches (p = 0.32) nor was there a significant difference in overall mortality (p = 0.07). CONCLUSION AND CLINICAL RELEVANCE: Overall, dogs undergoing cervical spinal surgery were less likely to survive until discharge compared with dogs undergoing thoracolumbar spinal surgery. Mortality in dogs undergoing cervical intervertebral disc decompression surgery was no different than for dogs undergoing thoracolumbar intervertebral disc decompression surgery. However, dogs undergoing cervical intervertebral disc decompression surgery should be considered at risk for aspiration pneumonia.

The hemodynamic effects of medetomidine continuous rate infusions in the dog.

OBJECTIVE: To characterize the hemodynamic effects of continuous rate infusions (CRI) of medetomidine administered at doses ranging from 0 to 3 microg kg(-1) hour(-1). STUDY DESIGN: Prospective, blinded, randomized experimental trial. ANIMALS: Six adult purpose-bred mongrel dogs. METHODS: Anesthesia was induced with sevoflurane for placement of arterial and venous catheters. Dogs recovered from anesthesia after which baseline hemodynamic measurements were obtained via lithium dilution cardiac output (CO) determination, with subsequent measurements via pulse power analysis to provide continuous CO determinations. Medetomidine, 1, 2, or 3 microg kg(-1) hour(-1) or a volume equivalent placebo, was administered via CRI for 60 minutes. Systolic, mean, and diastolic arterial pressure, heart rate (HR), CO and stroke volume were measured and stroke index (SI), cardiac index (CI), total peripheral resistance (TPR), and total peripheral resistance index (TPRI) were calculated at 3, 7, 10, 20, 30, 45, 60, 90, and 120 minutes from the start of the infusion. RESULTS: Increase in dose decreased SI by 25%, 19%, and 30%, HR by 33%, 57%, and 60%, CI by 50%, 65%, 70% and increased TPRI by 109%, 235%, and 222% from baseline to the 60-minute measurement for the 1, 2, and 3 microg kg(-1) hour(-1) doses, respectively. HR, TPRI, and CI all showed significant differences over the duration of the study from the placebo treatment. CONCLUSIONS: Medetomidine CRI produces clinically relevant changes in CO, TPR, and HR. The demonstrated decrease in CO is largely because of bradycardia and the degree of cardiovascular depression appears to be dose-dependent. These findings are consistent with previously described hemodynamic changes with single bolus administration of medetomidine. CLINICAL RELEVANCE: Low-dose medetomidine CRIs produce clinically relevant hemodynamic depression at doses as low as 1 microg kg(-1) hour(-1) and should be used cautiously in dogs.

Assessing clinical competency: reports from discussion groups.

This report describes proposed new models for assessment of eight of the nine clinical competencies the American Veterinary Medical Association Council on Education requires for accreditation. The models were developed by discussion groups at the Association of American Veterinary Medical Colleges' Clinical Competency Symposium. Clinical competencies and proposed models (in parentheses) are described. Competency 1: comprehensive patient diagnosis (neurologic examination on a dog, clinical reasoning skills); Competency 2: comprehensive treatment planning (concept mapping, computerized case studies); Competency 3: anesthesia, pain management (student portfolio); Competency 4: surgery skills (objective structured clinical examination, cased-based examination, "super dog" model); Competency 5: medicine skills (clinical reasoning and case management, skills checklist); Competency 6: emergency and intensive care case management (computerized case study or scenario); Competency 7: health promotion, disease prevention/biosecurity (360 degrees evaluation, case-based computer simulation); Competency 8: client communications and ethical conduct (Web-based evaluation forms, client survey, communicating with stakeholders, telephone conversation, written scenario-based cases). The report also describes faculty recognition for participating in clinical competency assessments.

Determination of minimum alveolar concentration of sevoflurane in juvenile swine.

Pigs are important animal models in veterinary and medical research and have been widely used in experiments requiring surgical anesthesia. Sevoflurane is an inhalant anesthetic with unique properties that make it an ideal anesthetic for mask induction and anesthesia maintenance. However, there are relatively few studies reporting the anesthetic requirements for sevoflurane in juvenile swine, an age group that is commonly used in research experiments. Therefore the objective of this study was to determine the Minimum Alveolar Concentration (MAC) for sevoflurane in juvenile swine. Sevoflurane anesthesia was induced in six Yorkshire-cross pigs of approximately 9 weeks-of-age and MAC for sevoflurane was determined. The sevoflurane MAC value was determined to be 3.5+/-0.1% which is notably higher than values reported in the literature for pigs. This discrepancy in MAC values may represent changes in anesthetic requirements between different age groups of pigs and differences in the type of stimulus used to determine MAC.