Protective effect of prone posture against hypergravity-induced arterial hypoxaemia in humans
| Autor: | Johan Petersson, Dag Linnarsson, Robb W. Glenny, Margareta Mure, Sten G. E. Lindahl, Malin Rohdin |
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| Rok vydání: | 2003 |
| Předmět: |
Adult
Male Supine position Physiology Hydrostatic pressure Hemodynamics Pulmonary Edema Hypergravity Respiratory physiology Oxygen Consumption Prone Position Supine Position Humans Medicine Hypoxia business.industry Oxygen transport Original Articles Arteries Oxygenation Pulmonary Alveoli Prone position Anesthesia Respiratory Mechanics Female Blood Gas Analysis business |
| Zdroj: | The Journal of Physiology. 548:585-591 |
| ISSN: | 0022-3751 |
| DOI: | 10.1113/jphysiol.2002.035956 |
| Popis: | Patients with acute respiratory distress syndrome have increased lung tissue weight and therefore an increased hydrostatic pressure gradient down the lung. Also, they have a better arterial oxygenation in prone (face down) than in supine (face up) posture. We hypothesized that this effect of the direction of gravity also existed in healthy humans, when increased hydrostatic gradients were induced by hypergravity. Ten healthy subjects were studied in a human centrifuge while exposed to 1 or 5 G in anterio-posterior (supine) or posterio-anterior (prone) direction. We measured blood gases using remote-controlled sampling and gas exchange by mass spectrometry. Hypergravity led to marked impairments of arterial oxygenation in both postures and more so in supine posture. At 5 G, the arterial oxygen saturation was 84.6 +/- 1.2 % (mean +/- S.E.M.) in supine and 89.7 +/- 1.4 % in prone posture (P < 0.001 for supine vs. prone). Ventilation and alveolar PO2 were increased at 5 G and did not differ between postures. The alveolar-to-arterial PO2 difference increased at 5 G to 8.0 +/- 0.2 kPa and 6.6 +/- 0.3 kPa in supine and prone postures (P = 0.003). Arterial oxygenation was less impaired in prone during hypergravity due to a better-preserved alveolo-arterial oxygen transport. We speculate that mammals have developed a cardiopulmonary structure that favours function with the gravitational vector in the posterio-anterior direction. |
| Databáze: | OpenAIRE |
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