To describe clinically relevant, physiological measurements collected during a 3 hour duration of alfaxalone total intravenous anaesthesia. Study design: Case series. Animals: A total of 112 client-owned middle-aged or older dogs.
Dogs were premedicated with intramuscular acepromazine (0.03 mg kg–1). Anaesthesia was induced and subsequently maintained for up to 3 hours with alfaxalone administered intravenously. Dogs breathed 100% oxygen via an endotracheal tube. Heart rate, respiratory rate and blood pressure were evaluated 30 minutes after administration of acepromazine and used as baseline values for comparisons of intra-anaesthetic data. Blood glucose was measured 1 week prior to anaesthesia and every hour during alfaxalone anaesthesia. Quality and duration of recovery were recorded. Mean data for physiological variables were compared over three time points—before induction of anaesthesia, for the first hour of anaesthesia and from 60 minutes to discontinuation of anaesthesia.
Mean induction dose of alfaxalone was 1.4 mg kg–1 [95% confidence interval (CI) 1.3–1.5). Post induction apnoea for >60 seconds occurred in 13 (11.6%) dogs. Mean alfaxalone infusion rate during the first 60 minutes of anaesthesia was 0.099 mg kg–1 minute–1; mean infusion rate was 0.092 mg kg–1 minute–1 from 60 minutes until discontinuation of anaesthesia. Heart rate was well maintained; hypotension (mean arterial blood pressure < 60 mmHg) was encountered in 23 (21%) dogs. Blood glucose levels did not alter during anaesthesia. Median time between discontinuation of alfaxalone infusion and extubation was 17 (7–35 minutes), time to assuming sternal recumbency was 75 (58–110 minutes), and time to standing was 109 (88–140 minutes).
Conclusions and clinical relevance:
Alfaxalone infusion provided effective anaesthesia in this population. In a minority of cases, respiratory and haemodynamic support of the patient was required.
- total intravenous anaesthesia