[The effects of conscious sedation by propofol on respiration during abdominal hysterectomy under spinal anesthesia].

The effects of conscious sedation by propofol on respiration were studied in 28 patients undergoing abdominal hysterectomy under spinal anesthesia. The patients were randomly assigned to receive conscious sedation by propofol (Group P, n = 20) or no sedation (Group C, n = 8). After a satisfactory level of analgesia had been achieved, a loading dose of propofol, 0.2 mg.kg-1 was administered every minute in Group P until patients exhibited spontaneous eye closure or nystagmus. Thereafter, the infusion rates were adjusted to maintain conscious sedation. Respiratory rate, SpO2 and nasal PETCO2 were measured every minute during the initial 30 minutes and subsequently at 5-min intervals. The patients were questioned on the 1st postoperative day concerning intraoperative recall and the level of satisfaction. The mean loading dose of propofol was 0.4 mg.kg-1 and the mean mainteinance rate was 1.7 +/- 0.5 mg.kg-1.h-1. Compared with Group C, the respiratory depression was less in Group P; SpO2 was significantly higher at 25 min after spinal tap and PETCO2 was significantly lower at 30 and 50 min after spinal tap in Group P. A score of patient satisfaction was significantly higher in Group P. Conscious sedation by propofol is a safe and useful supplement to spinal anesthesia for abdominal hysterectomy.