A comparison of subhypnotic doses of propofol and midazolam during spinal anaesthesia for elective Caesarean section.

Background: This study compared two types of sedation in pregnant women receiving subarachnoid anaesthesia for elective Caesarean section.

Methods: This prospective randomised study included 56 women. Patients were sedated with propofol (PROP group, n = 27) or midazolam (MID group, n = 29) via intravenous infusion after extraction of the foetus. The following parameters were assessed at five-minute intervals: degree of sedation, heart rate, arterial pressure, ECG recording and arterial haemoglobin oxygen saturation. Moreover, we recorded drug doses, changes in infusion rates to ensure a desirable degree of sedation and adverse side effects. The maternal recall of delivery and satisfaction with sedation were also evaluated.

Results: The incidence of increased sedative infusion rates was higher in the PROP group (59.3% vs. 37.9%). In contrast, decreased infusion rates were observed in the MID group (41.4% vs. 29.6%). After the initial dose, a desirable level of sedation was easier to obtain in the PROP group (77.7% vs. 55.1%), whereas excessive sedation was noted more frequently in the MID group (34.5% vs. 11.5%). The deepest degree of sedation was found in 2 PROP patients and 1 MID patient. In the PROP group, excessive sedation was rapidly alleviated by reducing the infusion rate. In the MID group, excessive sedation was observed throughout the examination, despite reduced infusion rates. No significant intergroup differences were found for desired sedation levels. The mean heart rate and arterial pressure were lower in the PROP group. In the MID group, only 5% of patients developed an elevated systolic RR. No ECG alterations were observed in any patient. A haemoglobin oxygen saturation level below 92% was found in 1 patient from each group. Logorrhoea was characteristic in the PROP group (44.4%). The incidence of nausea and vomiting were higher in the MID group. Other side effects (e.g., headache, backache, erythema and chills) were observed in a subset of patients from both groups. In the MID group, birth recall was significantly lower (82.8% vs. 96.3%). Full satisfaction with sedation was declared by 89.6% of MID patients and 92.6% of PROP patients.

Conclusions: Midazolam and propofol induce effective and safe sedation in patients receiving subarachnoid anaesthesia for Caesarean section. Propofol appears to be more useful for Caesarean section sedation when compared with midazolam because of its shorter action, antiemetic effects and better maternal recall of foetal delivery.