title: Hypoxic ventilatory response predicts the extent of maximal breath-holds in man.
abstract: To understand the factors influencing breath-holding performance, we tested whether the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR) were predictors of the extent of maximal breath-holds as measured by breath-hold duration, the lowest oxyhemoglobin saturation (SpO2min), lowest calculated PaO2 (PaO2min) and highest end-tidal PCO2 (PETCO2max) reached. Steady state isocapnic HVR and hyperoxic HCVR were measured in 17 human volunteers. Breath-holds were made at total lung capacity (TLC), at TLC following hyperventilation, at functional residual capacity, and at TLC with FIO2 = 0.15. SpO2 was measured continuously by pulse oximetry, and alveolar gas was measured at the end of breath-holds by mass spectrometry. PaO2min was calculated from SpO2min and PETCO2max. HVR was a significant predictor of both SpO2min and PaO2min. HVR and forced vital capacity were predictors of breath-hold duration by multiple linear regression. HCVR had no significant predictive value. We conclude that HVR, but not HCVR, is a significant predictor of breath-holding performance.
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000032:analysis / Q000502:physiology; D005260:Female; D005652:Functional Residual Capacity; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008451:Maximal Voluntary Ventilation; D010100:Oxygen / Q000032:analysis / Q000097:blood / Q000502:physiology; D010108:Oxyhemoglobins / Q000032:analysis / Q000502:physiology; D012119:Respiration; D013990:Tidal Volume; D014109:Total Lung Capacity
chemical_list: D010108:Oxyhemoglobins; D002245:Carbon Dioxide; D010100:Oxygen