Respiratory and cardiovascular effects of fentanyl during propofol-induced sedation under spinal anesthesia

To determine whether fentanyl augments respiratory and cardiovascular problems during propofol-induced sedation, we investigated the effects of propofol and fentanyl on respiratory and hemodynamic profiles in 30 female patients under spinal anesthesia, administering oxygen via face mask.

After spinal anesthesia, 20 patients were sedated with propofol (0.5 mg·kg^-1 bolus, 3 mg·kg^-1·h^-1), followed by administration of either 2 μg·kg^-1 fentanyl in group PF or normal saline in group P, whereas another 10 patients (group F) received 2 μg·kg^-1 fentanyl without propofol. We measured heart rate, mean arterial pressure, end-tidal carbon dioxide tension, and respiratory rate before and after treatment. We also evaluated apnea, arterial oxygen desaturation, and airway obstruction.

Mean arterial pressure was significantly lower in group P and PF than in group F. However, there were comparable changes in heart rate in the three groups. The combination of fentanyl and propofol decreased respiratory rate and increased end-tidal carbon dioxide tension more than fentanyl or propofol alone. Although apnea occurred in groups F and PF, arterial oxygen desaturation did not occur in any of the groups.

The combination of fentanyl and propofol augmented the risks of respiratory depression and apnea compared with the use of fentanyl or propofol alone.