Effects of the addition of low-dose ketamine to propofol-fentanyl anaesthesia during diagnostic gynaecological laparoscopy.

Objectives: Diagnostic gynaecological laparoscopy (DGL) is a brief procedure, generally performed on an outpatient basis. Propofol-fentanyl is often used for anaesthesia in minor outpatient procedures because of its rapid onset, short duration of action and smooth patient awakening. However, propofol has various cardiovascular effects such as reduced arterial pressure, cardiac output and cardiac index. Ketamine is an intravenous anaesthetic and short-acting analgesic that could alleviate the haemodynamic effects of propofol due to its sympathomimetic activity. The aim of this placebo-controlled trial was to evaluate the effects of the addition of low-dose ketamine to propofol-fentanyl anaesthesia in DGL.

Study Design: In this double-blind randomized trial, 60 healthy women undergoing gynaecological laparoscopy to investigate infertility were studied. Following injection of midazolam and fentanyl in all patients, the study group (n=30) received ketamine 0.5 mg/kg and propofol 1-2.5 mg/kg, and the placebo group (n=30) received saline 0.9% and propofol 1-2.5 mg/kg. Propofol was subsequently infused for the maintenance of anaesthesia.

Results: Patients in the study group had a significantly lower incidence of pain than patients in the placebo group during propofol injection (13% vs 87%, respectively; p<0.0001). After induction of anaesthesia, 16 (53%) patients in the placebo group and three (10%) patients in the study group had a decreased heart rate (p<0.001). The decrease in mean arterial pressure was greater in the placebo group compared with the study group (37% vs 7%, respectively; p<0.001). During the procedure, the total mean±standard deviation dose of propofol was 420±65 mg in the placebo group and 330±35 mg in the study group (p<0.001). Pain scores for the first 3h after the operation were significantly lower in the study group (p<0.001).

Conclusion: Use of low-dose ketamine with propofol-fentanyl anaesthesia in patients undergoing DGL was associated with less pain during propofol injection, lower incidence of haemodynamic changes, lower total dose of propofol and improved postoperative analgesia.