Efeito dos opióides e anestésicos sobre a temperatura corporal em gatos / Effects of opioids and anesthetic drugs on body temperature in cats

Effects of opioids and anesthetic drugs on body temperature in cats

1. Lysa P Posner¹, 
2. Alana A Pavuk¹, 
3. Jennifer L Rokshar¹, 
4. Jennifer E Carter¹, 
5. Jay F Levine²

Article first published online: 11 DEC 2009

DOI: 10.1111/j.1467-2995.2009.00508.x

© 2010 The Authors. Journal compilation © 2010 Association of Veterinary Anaesthetists

Issue

Veterinary Anaesthesia and Analgesia

Volume 37, Issue 1, pages 35–43, January 2010

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Abstract

Objective  To determine which class of opioid alone or in conjunction with other anesthetic drugs causes post-anesthetic hyperthermia in cats.

Study design  Prospective, randomized, crossover study.

Animals  Eight adult, healthy, cats (four spayed females and four castrated males weighing 3.8 ± 0.6 kg).

Methods  Each cat was instrumented with a wireless thermistor in the abdominal cavity. Temperature in all phases was recorded every 5 minutes for 5 hours. Population body temperature (PBT) was recorded for ∼8 days. Baseline body temperature is the final 24 hours of the PBT. All injectable drugs were given intramuscularly. The cats were administered drugs in four phases: 1) hydromorphone (H) 0.05, 0.1, or 0.2 mg kg⁻¹; 2) morphine (M) (0.5 mg kg⁻¹), buprenorphine (BUP) (0.02 mg kg⁻¹), or butorphanol (BUT) (0.2 mg kg⁻¹); 3) ketamine (K) (5 mg kg⁻¹) or ketamine (5 mg kg⁻¹) plus hydromorphone (0.1 mg kg⁻¹) (KH); 4) isoflurane in oxygen for 1 hour. Fifteen minutes prior to inhalant anesthetic, cats received either no premed (I), hydromorphone (0.1 mg kg⁻¹) (IH), or hydromorphone (0.1 mg kg⁻¹) plus ketamine (5 mg kg⁻¹) (IHK).

Results  Mean PBT for all unmedicated cats was 38.9 ± 0.6 °C (102.0 ± 1 °F). The temperature of cats administered all doses of hydromorphone increased from baseline (p < 0.03) All four opioids (H, M, BUP and BUT) studied increased body temperature compared with baseline (p < 0.005). A significant difference was observed between baseline temperature values and those in treatment KH (p < 0.03). Following recovery from anesthesia, temperature in treatments IH and IHK was different from baseline (p < 0.002).

Conclusions and clinical relevance  All of the opioids tested, alone or in combination with ketamine or isoflurane, caused an increase in body temperature. The increase seen was mild to moderate (<40.1 °C (104.2 °F) and self limiting.