Oxygen administration improves the serum level of nitric oxide metabolites in patients with obstructive sleep apnea syndrome.
OBJECTIVE
Nocturnal apnea and hypoxia are implicated in the pathogenesis of pulmonary and systemic hypertension in obstructive sleep apnea syndrome (OSAS). We have hypothesized that vasodilating factors including nitric oxide (NO) are affected by nocturnal apnea and hypoxia in patients with OSAS.


METHODS
We examined the serum level of NO production in 24 patients with OSAS (mean age 54.2+/-7.9 years) and 24 age-matched control subjects (53.4+/-8.1 years) and tested the effects of oxygen administration on the production of NO in the patients.


RESULTS
The serum level of nitrite/nitrates (NO(x)), which are stable metabolites of NO, was lower in patients with OSAS than in control subjects. Administration of 1-2 l/min of oxygen during night increased the patients' NO(x) level from 35.6+/-7.3 to 57.8+/-11.6 microM. Compressed air administration did not affect the NO(x) level in the patients.


CONCLUSIONS
These results indicate that systemic NO production is impaired in OSAS patients, possibly due to nocturnal hypoxia.
Department of Geriatric Medicine, Tokyo University Hospital, 7-3-1, Hongo Bunkyo-Ku, Tokyo 113-8655, Japan. shinjit-tky@umin.ac.jp
Shinji
S
Teramoto
Haruki
H
Kume
Takeshi
T
Matsuse
Takeo
T
Ishii
Akira
A
Miyashita
Masahiro
M
Akishita
Kenji
K
Toba
Yasuyoshi
Y
Ouchi
D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D010102:Oxygen Inhalation Therapy; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000628:therapy*
D009566:Nitrates; D009573:Nitrites