Transcutaneous and End-Tidal CO₂ Measurements in Hypoxia and Hyperoxia.

Transcutaneous measurement of carbon dioxide (CO₂) has been proposed for physiological monitoring of tactical jet aircrew because in some clinical settings it mirrors arterial CO₂ partial pressure (Pco₂). End-tidal monitoring in laboratory settings is known to give high-fidelity estimates of Pco₂. The correspondence between end-tidal (Pco₂) and transcutaneous Pco₂ (tcPco₂) was examined in healthy volunteers under laboratory conditions of hyperoxia and hypoxia.

Hyperoxia and Hypoxic Hypoxia Effects on Simple and Choice Reaction Times.

Introduction: Effects of exposure to hyperoxia (PiO2 > 105 mmHg), normoxia (PiO2 95-105 mmHg) and hypoxia (PiO2 < 95 mmHg) on simple and choice reaction performance tasks were evaluated.

Methods: Ten subjects performed simple and choice reaction time tests (SRT and CRT, respectively) at ground level for 40 min (20 min normoxic, 20 min hyperoxic, randomly assigned), 3048 m (10,000 ft) for 75 min (15 min hyperoxic, 60 min hypoxic), 4572 m (15,000 ft) for 60 min (15 min hyperoxic, 45 min hypoxic), and 6096 m (20,000 ft) for 35 min (15 min hyperoxic, 20 min hypoxic). SRT and CRT tests were also conducted at ground level 1 h after normoxic rest (recovery) to assess any recovery time effect on these psychomotor tasks.