title: Effects on man of 30-day exposure to a PICO2 of 14 torr (2 %): application to exposure limits.
abstract: Pulmonary function, acid-base balance, renal electrolyte excretion, hematology, biorhythms and psychomotor test results were studied in six men during 30 days of exposure to a PICO2 of 14 torr (FICO2 = 0.02) with pre- and postexposure periods on air. Alveolar and arterial PCO2 increased and remained constant throughout the CO2 exposure (delta PACO2 = delta PACO2 = 2.5 torr); the rise in expiratory minute volume (delta VE = 60%) was related to the increased tidal volume. Oxygen uptake and carbon dioxide output increased about 10% because of the ventilatory work overload. Physiological dead space increased 8% without an alveolar-arterial PCO2 difference. Respiratory acidosis was mild (delta pH approximately or equal to 0.01) and the renal response was slight. There was no variation in plasma electrolytes, except a slight decrease in potassium. Red blood cell count decreased, showing a confinement effect. Adaptation to exercise was slightly impaired. Results of electrobiological and psychomotor tests and biorhythm evaluations showed no variation; application of these findings to CO2 exposure limits is discussed.
mesh_terms: D000136:Acid-Base Equilibrium / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects; D004573:Electrolytes / Q000097:blood; D004909:Erythrocyte Indices / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008603:Mental Health; D005082:Physical Exertion; D012119:Respiration / Q000187:drug effects*
chemical_list: D004573:Electrolytes; D002245:Carbon Dioxide; D006854:Hydrocortisone