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PREDICTIVE STUDIES VII (PS VII): Interactions of Hyperoxia, Exercise, and Immersion in Neurologic O2 Poisoning.
Major Category: Oxygen toxicity and oxygenation. Immersion. Exercise. (PS VII)
Subcategory 8: Preliminary study, comparison of Middle Cerebral Artery Blood Flow Velocity (MCAvel) and ventilatory responses to exercise

a. "wet vs dry",
b. dry vs head-out,
c. dry vs head-in

Subcategory 2: Extension of CNS tolerance to hyperoxia

Stressors: exercise, immersion

Date: 1993

Expt. Title: Comparison of ventilatory responses to exercise with MCA velocity in "wet vs dry" Subjects. Expt. 13.01 (dry vs head-out) and Expt. 13.02 (dry vs head-in)

Description:

This was a preliminary study to resolve difficulties in use of the TCD underwater. The protocol, completed in 5 Subjects, involved exercise in the dry at 60, 100, 125, and 150 watts pedaling at the usual rate of 60 rpm. Immersed exercise was at 30, 43, 68 and 92 watts at 50 rpm. MCAvel as function of O2 uptake was the same wet vs dry in two Subjects, but in the other two, it was higher wet than dry. Major problems involved continued interference of water motion on the TCD signal, and pain due to pressure of the TCD probe on the subject’s head. This prompted removal of the probe after the "dry" run, and reapplication for the immersed experiment. As a result, additional measures to eliminate the effects of water motion on the TCD signal were innovated, and the method of stabilizing the TCD probe was improved to eliminate excess "holding" pressure to eliminate the pain.

Measurements:

MCA velocity, ventilation, and mixed expired O2 and CO2 for computation of rates of gas exchange, other.

07 February 2000 11:08:49 AM