Changes in respiratory control in humans induced by 8 h of hyperoxia.

Journal article

In humans, 8 h of isocapnic hypoxia causes a progressive rise in ventilation associated with increases in the acute ventilatory responses to hypoxia (AHVR) and hypercapnia (AHCVR). To determine whether 8 h of hyperoxia causes the converse of these effects, three 8-h protocols were compared in 14 subjects: 1) poikilocapnic hyperoxia, with end-tidal PO(2) (PET(O(2))) = 300 Torr and end-tidal PCO(2) (PET(CO(2))) uncontrolled; 2) isocapnic hyperoxia, with PET(O(2)) = 300 Torr and PET(CO(2)) maintained at the subject's normal air-breathing level; and 3) control. Ventilation was measured hourly. AHVR and AHCVR were determined before and 0.5 h after each exposure. During isocapnic hyperoxia, after an initial increase, ventilation progressively declined (P < 0.01, ANOVA). After exposure to hyperoxia, 1) AHVR declined (P < 0.05); 2) ventilation at fixed PET(CO(2)) decreased (P < 0.05); and 3) air-breathing PET(CO(2)) increased (P < 0.05); but 4) no significant changes in AHCVR or intercept were demonstrated. In conclusion, 8 h of hyperoxia have some effects opposite to those found with 8 h of hypoxia, indicating that there may be some "acclimatization to hypoxia" at normal sea-level values of PO(2).

Authors: Ren, X; Fatemian, M; Robbins, P

• Publication status: Published
• Journal: Journal of applied physiology (Bethesda, Md. : 1985)
• Volume: 89
• Issue: 2
• Pages: 655-662
• Publication date: 2000-08-01
• EISSN: 1522-1601
• ISSN: 8750-7587
• Language: English
• Keywords: Adolescent; Models, Biological; Humans; Hyperoxia; Hydrogen-Ion Concentration; Adult; Middle Aged; Female; Algorithms; Male; Oxygen; Blood Gas Analysis; Respiratory Mechanics; Chemoreceptor Cells; Carbon Dioxide