In a retrospective postmortem investigation of anesthetic-associated death (AAD) in cats presented to high-quality, highvolume spay/neuter organizations, AAD was defined as death occurring within 24 hours of anesthesia. Fifty-two of 54 study cats went into cardiopulmonary arrest within minutes to 24 hours from the time of premedication. The remaining 2 were euthanized after failing to recover within 24 hours. Twenty-eight cats died after receiving a combination of premedication and induction agents; 1 died after receiving premedication alone. Four other cats died intraoperatively, and 21 died postoperatively. In addition to gross inspection, histologic examination of major organs was performed in nearly all cases. Significant gross and/or microscopic preexisting disease was detected in 33%, with pulmonary disease diagnosed most frequently (24%), including Aelurostrongylus abstrusus infection (9%). Heart disease was less frequent (11%) and included 2 cases of hypertrophic cardiomyopathy. An additional 4% died from surgical complications. No significant disease was detected in 63% of cases. The rate of AADs in the 2 study spay/neuter organizations was generally low (0.8 and 1.6 per 1000 procedures). Additional studies are needed to determine if these findings are representative of AAD in other populations of cats.

Commentary
This article provided useful data on AAD in cats as well as on the prevalence of A abstrusus infection. However, the data should have raised critical questions on how veterinarians should handle AAD. In particular, given the large decrease in human AAD when rigorous evaluation processes are mandated, when should similar investigations for veterinary cases be legally mandated? Although at 0.8 and 1.6 per 1000 procedures the rates of AAD in this study were similar to those previously reported, they are 800 to 1600 times higher than the 1 per 100,000 procedures reported in humans.1 Equally striking is the timing of the AAD in this study—almost 90% of deaths occurred before or after the procedure when monitoring is generally least frequent. Could those cats have survived with enhanced anesthetist training? Also of note: Of the 2211 recorded human anesthesia-related deaths in the United States from 1999 to 2005, 47% were attributable to anesthetic overdose.1 If nearly 50% of deaths are due to anesthetic overdoses, then it is feasible that similar avoidable errors are made in veterinary medicine. In this study, 63% of feline deaths had no gross or histologic findings. Armed with this information, the veterinary profession should actively evaluate how to lower the AAD rate, regardless of the impact on the cost of care.—Paula F.Moon-Massat, DVM, DACVA

Source
Post-mortem findings in 54 cases of anesthetic associated death in cats from two spay-neuter programs in New York State. Gerdin JA, Slater MR,Makolinski KV, et al. J FELINEMED SURG 13:959-966, 2011.

1. Epidemiology of anesthesia-related mortality in the United States, 1999-2005. Li G,Warner M, Lang BH, et al. Anesthesiology 110:759-765, 2009.