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This Article Full Text Full Text (PDF) All Versions of this Article: 295/2/H778    most recent 00653.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Gilmartin, G. S. Articles by Weiss, J. W. Search for Related Content PubMed PubMed Citation Articles by Gilmartin, G. S. Articles by Weiss, J. W.

Ventilatory, hemodynamic, sympathetic nervous system, and vascular reactivity changes after recurrent nocturnal sustained hypoxia in humans

¹Pulmonary and Sleep Research Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts; and ²Laboratoire du Sommeil, Laboratoire HP2 (Hypoxie Pathophysiologie), Institut National de la Santé et de la Recherche Médicale ERI 0017, Centre Hospitalier Universitaire de Grenoble, Grenoble, France

Submitted 6 June 2007 ; accepted in final form 2 June 2008

Recurrent and intermittent nocturnal hypoxia is characteristic of several diseases including chronic obstructive pulmonary disease, congestive heart failure, obesity-hypoventilation syndrome, and obstructive sleep apnea. The contribution of hypoxia to cardiovascular morbidity and mortality in these disease states is unclear, however. To investigate the impact of recurrent nocturnal hypoxia on hemodynamics, sympathetic activity, and vascular tone we evaluated 10 normal volunteers before and after 14 nights of nocturnal sustained hypoxia (mean oxygen saturation 84.2%, 9 h/night). Over the exposure, subjects exhibited ventilatory acclimatization to hypoxia as evidenced by an increase in resting ventilation (arterial PCO₂ 41.8 ± 1.5 vs. 37.5 ± 1.3 mmHg, mean ± SD; P < 0.05) and in the isocapnic hypoxic ventilatory response (slope 0.49 ± 0.1 vs. 1.32 ± 0.2 l/min per 1% fall in saturation; P < 0.05). Subjects exhibited a significant increase in mean arterial pressure (86.7 ± 6.1 vs. 90.5 ± 7.6 mmHg; P < 0.001), muscle sympathetic nerve activity (20.8 ± 2.8 vs. 28.2 ± 3.3 bursts/min; P < 0.01), and forearm vascular resistance (39.6 ± 3.5 vs. 47.5 ± 4.8 mmHg·ml^–1·100 g tissue·min; P < 0.05). Forearm blood flow during acute isocapnic hypoxia was increased after exposure but during selective brachial intra-arterial vascular infusion of the alpha-blocker phentolamine it was unchanged after exposure. Finally, there was a decrease in reactive hyperemia to 15 min of forearm ischemia after the hypoxic exposure. Recurrent nocturnal hypoxia thus increases sympathetic activity and alters peripheral vascular tone. These changes may contribute to the increased cardiovascular and cerebrovascular risk associated with clinical diseases that are associated with chronic recurrent hypoxia.

acclimatization; vascular resistance; pathophysiology; chronic obstructive pulmonary disease

This article has been cited by other articles:

				R. Tamisier, G. S. Gilmartin, S. H. Launois, J. L. Pepin, H. Nespoulet, R. Thomas, P. Levy, and J. W. Weiss A new model of chronic intermittent hypoxia in humans: effect on ventilation, sleep, and blood pressure J Appl Physiol, July 1, 2009; 107(1): 17 - 24. [Abstract] [Full Text] [PDF]