CO2 Chemosensitivity during Immersion in Humans

Lu-Peng Chang ； Claes E. G. Lundgren

《The Chinese Journal of Physiology》 38卷1期 (1995/03) Pp. 7-12

並列摘要

Hypercapnic ventilatory response was compared in 9 seated subjects during head-out immersion in 35°C (thermoneutral) water and during non-immersion in 28 °C (thermoneutral) room air. Using Read’s C02-rebreathing technique, minute ventilation (V(subscript E)) and end-tidal (ET) P(subscript CO2) were sampled continuously for 4-5 min with a spirometer and a mass spectrometer, while the subjcct rebreathed a 6 L gas mixture initially containing 7% CO2 and 93% O2 in a bag-in-box system. The slope of the hypercapnic ventilatory response curve, expressed as △V(subscript E)/△P(subscript ETCO2), ranged from 0.76 to 2.49 L/min/ mmHg. Immersion affected neither the slope nor the position of the hypercapnic ventilatory response curve. The rate of rise of P ETCOZ during immersed CO 2-rebreathing was significantly reduced (4.47 ±0.19 [SE] mmHg/min), as compared to the control value (5.67 ±0.24). It was concluded that the CO2 chemosensitivity during immersion in humans did not change and that the capacity to store CO2 in tissue might have been increased.

並列關鍵字

diving ； head-out water immersion ； hypercapnic ventilatory response ； CO2 sensitivity ； CO2 storage capacity