Dynamics of the control of ventilation during metabolic acidosis and its correction.

The purpose of this study was to attempt a more precise partition of the respiratory driving forces that arise from the arterial and from the medullary H+-sensitive receptors during metabolic acidosis. The combined output of the peripheral and central chemoreceptors measured as the ventilatory response to acidosis was analyzed in relation to the arterial and cerebrospinal (CSF) acid-base status during the successive phases of metabolic acidosis, i.e.: the periods of induction, maintenance, correction, and recovery. In 12 awake trained dogs, severe acidosis was induced in one hour and was maintained for 7 hours with infusion of HCl. Then, arterial pH was rapidly returned to normal with a 15-min intravenous infusion of bicarbonate, and the dogs were permitted to recover for 16 hours. At intervals during the 24 hours, we assessed the central and peripheral chemoreceptor drives of breathing by simultaneous determination of the acid-base status of blood and CSF and by measurements of the resulting ventilation....