Use of a propofol infusion for anaesthetic maintenance in Guinea pigs (Cavia porcellus): a retrospective case series

Abstract

ObjectiveTo retrospectively evaluate the feasibility of a propofol infusion for anaesthetic maintenance in guinea pigs. Study designRetrospective case series. AnimalsClient-owned guinea pigs undergoing general anaesthesia. MethodsAnaesthetic records of guinea pigs anaesthetized between March 2015 and March 2018 were reviewed. Animals administered a propofol infusion for > 20 minutes were identified and evaluated. Procedure performed, pre-anaesthetic medication, preoperative and intraoperative respiratory rate (fR) and heart rates (HRs), total amount of propofol administered, total anaesthesia and recovery times were extracted from the records and analysed using descriptive statistics and Pearson correlation tests. Data are reported as mean (range). ResultsRecords of 14 animals meeting the criteria were identified. Following drug combinations were administered for premedication: butorphanol 0.43 (0.3–0.5) mg kg–1, medetomidine 0.1 (0.05–0.2) mg kg–1 and midazolam 1 (0.5–2) mg kg–1 (n = 3); methadone 0.33 (0.25–0.5) mg kg–1, medetomidine 0.07 (0.01–0.1) mg kg–1 and midazolam 0.66 (0.5–1) mg kg–1 (n = 3); butorphanol 0.5 mg kg–1, medetomidine 0.05 mg kg–1 and ketamine 5 mg kg–1 (n = 2); buprenorphine 0.01 mg kg–1, medetomidine 0.07 (0.04–1) mg kg–1 and ketamine 4 (3–5) mg kg–1 (n = 3); butorphanol 0.5 mg kg–1, alfaxalone 1 mg kg–1 and midazolam 0.5 mg kg–1 (n = 1); and methadone 0.38 (0.25–0.5) mg kg–1, medetomidine 0.08 (0.06–1) mg kg–1 with midazolam 0.75 (0.5–1) mg kg–1 (n = 2).Preoperative and intraoperative HRs were 240 (160–300) and 170 (140–200) beats minute–1, respectively. Preoperative and intraoperative fR were 63 (50–86) and 37 (18–80) breaths minute–1, respectively. The propofol infusion rate was 0.45 (0.17–0.80) mg kg–1 minute–1. Total anaesthesia and recovery times were 60 (25–145) and 17 (8–60) minutes, respectively. A slight correlation was found between total propofol dose infused and recovery time (r = 0.58). Conclusion and clinical relevancePropofol infusions may be a useful alternative to inhalant anaesthetics.