title: Occlusion of the upper airway does not augment the cardiovascular response to arousal from sleep in humans.
abstract: The cardiovascular response to an arousal from sleep at the termination of an obstructive apnea is more than double that to a spontaneous arousal. We investigated the hypothesis that stimulation of respiratory mechanoreceptors, by inspiring against an occluded airway during an arousal from sleep, augments the accompanying cardiovascular response. Arousals (>10 s) from stage 2 sleep were induced by a 1-s auditory tone (85 dB) during a concomitant 1-s inspiratory occlusion (O) and without an occlusion [i.e., control arousal (C)] in 15 healthy men (mean +/- SE: age, 25 +/- 1 yr). Arousals were associated with a significant increase in mean arterial blood pressure (MAP) at 4 s (P < 0.001) and a significant decrease in R-R interval at 3 s (P < 0.001). However, the magnitude of the cardiovascular response was not different during C compared with O (MAP: C, 86 +/- 3 to 104 +/- 3 mmHg; O, 86 +/- 3 to 105 +/- 3 mmHg; P = 0.99. R-R interval: C, 1.12 +/- 0.03 to 0.89 +/- 0.04 s; O, 1.11 +/- 0.02 to 0.87 +/- 0.02 s, P = 0.99). Ventilation significantly increased during arousals under both conditions at the second breath (P < 0.001); this increase was not different between the two conditions (C: 4.40 +/- 0.29 to 6.76 +/- 0.61 l/min, O: 4.35 +/- 0.34 to 7.65 +/- 0.73 l/min; P = 0.31). We conclude that stimulation of the respiratory mechanoreceptors by transient upper airway occlusion is unlikely to interact with the arousal-related autonomic outflow to augment the cardiovascular response in healthy young men.
authors.affiliation: Clinical and Academic Unit of Sleep and Breathing, Royal Brompton Hospital, Sydney St., London SW3 6NP, UK. d.odriscoll@imperial.ac.uk
authors.forename: Denise M
authors.initials: DM
authors.lastname: O'Driscoll
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kostikas
authors.forename: Anita K
authors.initials: AK
authors.lastname: Simonds
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Morrell
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001143:Arousal / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D012123:Pulmonary Ventilation / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*