Respiratory effects of fentanyl, diazepam, and methohexital sedation

The respiratory depressant effects of fentanyl, diazepam, and methohexital were studied in 18 patients who were breathing room air. Two patients had 70% oxygen supplementation administered by a nasal inhaler. Varying degrees of hypoxia occurred when the narcotic was given but hypoxia was not seen in patients who received diazepam alone. The hypoxic changes may be attributed to various physiological responses and can probably be prevented with administration of adequate oxygen.