TY - JOUR
T1 - Role of hypoxemia in sleep apnea-induced sympathoexcitation
AU - Smith, Michael L.
AU - Niedermaier, Otfried N.W.
AU - Hardy, Seth M.
AU - Decker, Michael J.
AU - Strohl, Kingman P.
N1 - Funding Information:
The authors acknowledge Ms. Jean Arnold for her excellent technical assistance. This research was supported, in part, by grants HL49266 and HL30506 from the National Heart, Lung and Blood Institute, National Institutes of Health (Bethesda, MD, USA).
PY - 1996/1/5
Y1 - 1996/1/5
N2 - The importance of hypoxemia in determining sympathoexcitation during obstructive sleep apnea was examined by comparing changes in efferent sympathetic nerve activity (SNA) during spontaneous obstructive apneas with hypoxemia alone of similar magnitude and duration induced by 1-4 breaths of 100% nitrogen in six patients with obstructive sleep apnea and with spontaneous apneas while breathing 100% oxygen (apnea without hypoxemia) in three patients. In addition, eight control subjects were studied during induced hypoxemia. The magnitude of sympathoexcitation during spontaneous apneas (103 ± 15%) was more than twice that observed during induced hypoxemia (47 ± 14%) during episodes in which the nadir of oxygen desaturation (78 ± 2 and 75 ± 2%, respectively) and duration of hypoxemia (27 ± 3 and 33 ± 3 s, respectively) were the same (P > 0.20). Similarly, in three patients SNA increased 115% during normoxic spontaneous obstructive apneas, but increased only 43% during hyperoxic spontaneous obstructive apneas in which oxygen saturation did not decrease significantly. Sympathetic neural responses to induced hypoxemia in control subjects (17 ± 7%) were significantly less than that of the sleep apnea patients. We conclude that hypoxemia contributes importantly, but is not the sole determinant of the sympathoexcitation provoked during episodes of obstructive sleep apnea.
AB - The importance of hypoxemia in determining sympathoexcitation during obstructive sleep apnea was examined by comparing changes in efferent sympathetic nerve activity (SNA) during spontaneous obstructive apneas with hypoxemia alone of similar magnitude and duration induced by 1-4 breaths of 100% nitrogen in six patients with obstructive sleep apnea and with spontaneous apneas while breathing 100% oxygen (apnea without hypoxemia) in three patients. In addition, eight control subjects were studied during induced hypoxemia. The magnitude of sympathoexcitation during spontaneous apneas (103 ± 15%) was more than twice that observed during induced hypoxemia (47 ± 14%) during episodes in which the nadir of oxygen desaturation (78 ± 2 and 75 ± 2%, respectively) and duration of hypoxemia (27 ± 3 and 33 ± 3 s, respectively) were the same (P > 0.20). Similarly, in three patients SNA increased 115% during normoxic spontaneous obstructive apneas, but increased only 43% during hyperoxic spontaneous obstructive apneas in which oxygen saturation did not decrease significantly. Sympathetic neural responses to induced hypoxemia in control subjects (17 ± 7%) were significantly less than that of the sleep apnea patients. We conclude that hypoxemia contributes importantly, but is not the sole determinant of the sympathoexcitation provoked during episodes of obstructive sleep apnea.
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U2 - 10.1016/0165-1838(95)00062-3
DO - 10.1016/0165-1838(95)00062-3
M3 - Article
C2 - 8847442
AN - SCOPUS:0030052594
SN - 0165-1838
VL - 56
SP - 184
EP - 190
JO - Journal of the Autonomic Nervous System
JF - Journal of the Autonomic Nervous System
IS - 3
ER -