| Title | Relationship between arterial oxygen saturation and heart rate variability at high altitudes. | ||
| Author | Saito, Shigeru; Tanobe, Kyoko; Yamada, Makiko; Nishihara, Fumio | ||
| Journal | Am J Emerg Med | Publication Year/Month | 2005-Jan |
| PMID | 15672330 | PMCID | -N/A- |
| Affiliation | 1.Department of Anesthesiology, Gunma University School of Medicine, Maebashi 371-8511, Japan. shigerus@showa.gunma-u.ac.jp. | ||
Autonomic nervous systems have important roles for survival of victims under hypobaric hypoxic condition. In the present study, we assessed the correlation between arterial oxygen saturation (Sp O 2 ) and heart rate variability (HRV) to identify the autonomic nervous responsiveness among trekkers at high altitude (n = 21). HRV was analyzed by the maximum entropy method. Sp O 2 among subjects at 3456 m (495 mm Hg) was 80% +/- 5% (mean +/- SD; range, 69%-93%). Sp O 2 and percentile entropy, and Sp O 2 and low-frequency variability, had positive correlation ( r = 0.455 and 0.518, respectively). Sp O 2 value among subjects with mountain sickness symptoms was not different from that among subjects without the symptoms. In conclusion, autonomic responses among high-altitude trekkers may be blunted under hypobaric hypoxic conditions. Deterioration of autonomic function measured by HRV might be more sensitive to hypoxia than clinical symptoms at high altitudes.