[Remifentanil or propofol for sedation in subarachnoid anesthesia. Effects on ventilation, hemodynamic stability and...

To compare depth of sedation, hemodynamic and respiratory effects, and bispectral index (BIS) in surgical patients under subarachnoid anesthesia with intravenous perfusion of 1 mg/kg/h of propofol or 3 microgram/kg/h of remifentanil or placebo.

Fifty-one elective surgery patients were randomly assigned to one of 3 groups: propofol (n = 17), remifentanil (n = 17) or placebo (n = 17). We monitored ECG, blood pressure (BP), respiratory frequency (RF), oxygen saturation by pulse oximetry (SpO2), nasal end tidal carbon dioxide pressure (PETCO2), BIS and sedation on the Observer's Assessment of Alertness/Sedation scale (OAA/S). Five minutes after starting subarachnoid anesthesia, we initiated the assigned intravenous perfusion. Measurement of hemodynamic variables, BIS, PETCO2, RF and OAA/S score occurred at baseline, every 5 minutes during surgery and after withdrawal of sedation at intervals until recovery of baseline values.

Patient data and SpO2 were similar in the 3 groups. PETCO2, FR and OAA/S did not change significantly from baseline in the placebo group but were significantly different in the other groups. BIS was significantly lower in the propofol group than in either the remifentanil or the control group. Times to recovery were similar in the two sedation groups. Slight complications were observed in 35.3% patients in the propofol group, 53.3% in the remifentanil group and 7.7% in the placebo group; complications were mainly nausea, pruritus and hypoventilation in the remifentanil group and venous pain in the propofol group.

The sedation regimens used were safe and adequate. Propofol is associated with fewer complications than remifentanil.