Effect of Immersion on the Exchange of Oxygen in the Lung.
NAVY EXPERIMENTAL DIVING UNIT WASHINGTON D C
Pagination or Media Count:
Steady state pulmonary gas exchange measurements were obtained in two resting subjects breathing a mixture of helium and oxygen at a simulated depth of 5 feet of sea water in a hyperbaric chamber. Measurements were obtained first with the subjects in a dry environment and then with the subjects immersed to the chin in warm water. Immersion was associated with a 1.3-1.7 mmHg increase in arterial carbon dioxide tension, a 13.2-13.3 mmHg decrease in arterial oxygen tension, and a 12.0-15.6 mmHg rise in alveolar-arterial oxygen gradient. Respiratory frequency, minute ventilation, tidal volume, and oxygen consumption remained unchanged. Physiologic dead space decreased slightly in one subject, but remained unchanged in the other. The observed impairment in oxygenation of arterial blood is thought to be related to the development of alveoli in the lung bases with ratios of ventilation to perfusion significantly less than one. Author
- Stress Physiology