Possible mechanisms that may determine the set point and sensitivities of the chemoreflexes.

Abstract

A century ago, Haldane and Priestley demonstrated the exquisite sensitivity of ventilation (VE) to small variations in alveolar PCO2 6. This belief in the primacy of CO2 over O2 in the regulation of V E has persisted through into modern physiology, for example, in his textbook on Respiratory Physiology15, West writes, “The most important factor in the control of ventilation under normal conditions is the PCO2 of the arterial blood.” Indeed, a reasonable estimate is that ventilation is 30 fold more sensitive to acute variations in Pco2 compared with Po2 for blood gas tensions around sea level.