Drug-induced arterial pressure elevation is associated with arousal from NREM sleep in normal volunteers

Abrupt changes in arterial pressure produce arousal in sleeping animals. To determine whether arterial pressure elevations can cause arousal from slee p in humans, we studied five healthy individuals without sleep complaints o r cardiac abnormalities. Monitoring included electroencephalogram, electroo culogram, and electromyogram to determine stage sleep; finger cuff to measu re arterial pressure; and electrocardiogram to measure heart rate. We admin istered intravenous bolus doses of either phenylephrine or saline after per forming a dose-response curve to establish the amount of phenylephrine that produced a 20-mmHg increase in mean arterial pressure. Ten boluses of phen ylephrine and ten boluses of saline were then administered in random order during stable non-rapid-eye-movement sleep. An observer blinded to the orde r of drug administration identified arousals using a standard definition. A rousals were five times more likely to occur after phenylephrine than after saline (58 vs. 12%; P = 0.0071). Phenylephrine administration produced hea rt rate slowing, indicative of baroreflex stimulation. We conclude that pha rmacologically induced arterial pressure elevation is associated with arous al from sleep in normal volunteers.