Anesthesiology
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Randomized Controlled Trial Clinical Trial
Dose-response pharmacology of intrathecal morphine in human volunteers.
Intrathecal morphine sulfate (ITMS) administration was introduced into clinical practice in 1979. Inadequate information exists delineating ITMS respiratory effects in the dosage range most frequently employed today. This study evaluated 0.2, 0.4, and 0.6 mg ITMS in male volunteers. ⋯ ITMS produced dose-related analgesia and respiratory depression in nonsurgical healthy, young, adult male volunteers. Respiratory depression was significant after 0.2 or 0.4 mg and profound and prolonged after 0.6 mg. No clinical signs or symptoms, including respiratory rate, reliably indicated hypoxemia. Pulse oximetry reliably detected hypoxemia after ITMS, and supplemental nasal oxygen (2 L/min) effectively corrected this hypoxemia.