title: Risk of anaesthetic mortality in dogs and cats: an observational cohort study of 3546 cases.
abstract: OBJECTIVE
  To evaluate the anaesthetic death risk for dogs and cats in a French private practice.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  All small animals anesthetized at the Centre Hospitalier Vétérinaire des Cordeliers between April 15th, 2008 and April 15th, 2010.
  
  
  METHODS
  General anaesthesia was defined as a drug-induced unconsciousness characterised by a controlled and reversible depression of the central nervous system and analgesia, sufficient to allow endotracheal intubation. Patient outcome (alive or dead) was assessed at the end of anaesthesia defined as the meeting point of the return of consciousness, rectal temperature >36 °C and ability to maintain sternal recumbency. Death occurring during anaesthesia was recorded. Relationship between anaesthetic death and ASA status, species, age, nature of the procedure, anaesthetic protocol and occurrence of epidural administration of a combination of morphine and bupivacaine were analysed.
  
  
  RESULTS
  During the study period 3546 animals underwent general anaesthesia. The overall death rate in the present study was 1.35% (48 in 3546, 95% CI 0.96-1.75). The death rate of healthy animals (ASA 1 and 2) was 0.12% (3 in 2602 95% CI 0.02-0.34). For sick animals (ASA status 3 and over), the overall death rate was 4.77% (45 in 944 95% CI 3.36-6.18). The death rates in the ASA 3, 4 and 5 categories were 2.90%, 7.58% and 17.33%, respectively. The main factor associated with increased odds of anaesthetic death in ASA categories 3 and over was poor health status (ASA physical status classification). The nature of the procedure the patient underwent and epidural administration of a combination of morphine and bupivacaine were not correlated with the occurrence of death during anaesthesia. Neither species nor age effects were detected.
  
  
  CONCLUSIONS
  Specific factors were associated with increased odds of anaesthetic death, especially poor health status. Efforts must be directed towards thorough preoperative patient evaluation and improvement of clinical conditions if possible. Identification of risk factors before anaesthesia should lead to increased surveillance by trained staff. This could result in better outcomes.
authors.affiliation: Centre Hospitalier Vétérinaire des Cordeliers, Meaux, France. cbille@chvcordeliers.com
authors.forename: Christophe
authors.initials: C
authors.lastname: Bille
authors.forename: Vincent
authors.initials: V
authors.lastname: Auvigne
authors.forename: Stéphane
authors.initials: S
authors.lastname: Libermann
authors.forename: Eric
authors.initials: E
authors.lastname: Bomassi
authors.forename: Philippe
authors.initials: P
authors.lastname: Durieux
authors.forename: Elise
authors.initials: E
authors.lastname: Rattez
mesh_terms: D000768:Anesthesia, General / Q000401:mortality / Q000662:veterinary*; D000777:Anesthetics / Q000009:adverse effects*; D018685:Anesthetics, Inhalation / Q000009:adverse effects; D018686:Anesthetics, Intravenous / Q000009:adverse effects; D000818:Animals; D002415:Cats; D004285:Dogs; D007530:Isoflurane / Q000009:adverse effects; D011229:Preanesthetic Medication / Q000009:adverse effects / Q000401:mortality / Q000662:veterinary; D012307:Risk Factors; D013874:Thiopental / Q000009:adverse effects
chemical_list: D000777:Anesthetics; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D007530:Isoflurane; D013874:Thiopental