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PREDICTIVE STUDIES VIII (PS VIII): CO2 and Adaptation to Acute Hypoxia
Major Category: CO2 and adaptation to acute hypoxia (PS VIII)
Subcategory 7: Physiological responses to inspiratory hypoxia and hypoxia with 4% CO2 at rest at 1 ATA

Date: September - October 1994

Expt. Title Acronym: PERCH = Physiological (responses to) Exercise (and) Rest (while breathing) CO2 (and) Hypoxic (gas mixture).

Expt. Title: PERCH 1. Physiological responses to inspired gas mixtures of air, 10% O2,and 10% O2 with 4% CO2 at-rest and during 50 and 100 watts of bicycle ergometer exercise. (Expt. 14.00, 14.21)

Description:

These experiments differ from the preceding ones in that the middle cerebral artery blood flow velocity (MCAvel) and cardiac output were added to the physiological measurements, and tests of mental performance were not used, so full concentration could be on the physiological responses. The experiment protocol was a 5 min. air control period at-rest, followed by 10 min. at-rest breathing the test gas, then 6 min. each at 50 and 100 watt exercise levels, followed by 5 min. at rest still breathing the test gas. This protocol was followed three times in the same day with three different inspired gas mixtures: air, 10% O2 / 4% CO2, and 10% O2 at 1 ATA. The subject population was N = 7.

Measurements:
Physiological:

Arterial O2 saturation, heart rate, end-tidal PCO2 and PO2, ventilation, middle cerebral artery blood flow velocity, and cardiac stroke volume. Inspired O2 and CO2 concentrations monitored with digital indicators and controlled to + 0.1%

REPORT: Gelfand, R., C. J. Lambertsen, G. Beck, Jr., and J. M. Clark. Dynamic responses of S_aO2 and "CBF" to abrupt exposure to inhaled 10% O2 / 4% CO2 at rest, followed by 50 and 100 watts exercise (ABSTRACT). Undersea Hyperbaric Med. 22(Supp.): 70-71, 1995.

07 February 2000 11:48:56 AM