Effects of opioids and anesthetic drugs on body temperature in cats
Article first published online: 11 DEC 2009
© 2010 The Authors. Journal compilation © 2010 Association of Veterinary Anaesthetists
Veterinary Anaesthesia and Analgesia
Volume 37, Issue 1, pages 35–43, January 2010
How to Cite
Posner, L. P., Pavuk, A. A., Rokshar, J. L., Carter, J. E. and Levine, J. F. (2010), Effects of opioids and anesthetic drugs on body temperature in cats. Veterinary Anaesthesia and Analgesia, 37: 35–43. doi: 10.1111/j.1467-2995.2009.00508.x
- Issue published online: 11 DEC 2009
- Article first published online: 11 DEC 2009
- Received 20 May 2008; accepted 15 March 2009.
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.