Evaluation of the gravimetric method of propofol infusion with intermittent ketamine injections for total intravenous anaesthesia (TIVA)

Forty four patients scheduled for elective surgery of short to moderate duration (< 90 minutes) were recruited into this study. Anaesthesia was induced with intravenous propofol 2.5mg/kg and maintained with continuous intravenous infusion of pre-mixed propofol and normal saline containing 2mg/ml of propofol. Suxamethonium 1mg/kg was used to facilitate endotracheal intubation. No long-acting muscle relaxant was used. Intravenous ketamine 0.5mg/kg stat dose was given for analgesic supplement, and 0.25mg/kg subsequent intermittent doses on signs of inadequate anaesthesia. The propofol infusion was stopped at the end of the surgery. Mean duration of anaesthesia was 56.5 ± 2.6 minutes while mean recovery time was 10.6 ± 4.6 minutes. The mean post-anaesthetic recovery scores (PARS) were 4.35/6, 5.17/6, 5.80/6 and 5.85/6 at admission to the recovery room and after 15 minutes, 30 minutes and discharge to the ward respectively. There were no incidents of extreme haemodynamic fluctuations or emergence phenomena noticed in any of the patients.