THE WORK OF BREATHING AND ITS RELATION TO RESPIRATORY ACIDOSIS

Publisher Website
Google Scholar
Abstract
(Editorial) This paper deals with the metabolic cost of breathing and its relation to arterial PCo2 in normal subjects and in patients with obstructive disease of the airways. The O2 cost of breathing is plotted against total ventilation for normal and obstructed breathing. This information is when replotted in terms of CO2 output and alveolar ventilation, using assumed values for respiratory quotient and dead space. Isopleths radiating from the origin are added, representing different values of alveolar, or arterial, PCo2. This graph shows that PCo2 passes through a minimal value and then increases as ventilation is still further increased, because the production of CO2 by the muscles of respiration is faster, on a percentile basis, than the increase in alveolar ventilation. O2 consumption available for non-ventilatory work is then plotted against total ventilation, at stated values of alveolar PC02. This graph demonstrates that an increase in the work of breathing seriously curtails the amount of O2 which is avail-able for non-ventilatory work, and that an increase in alveolar PC02 in-creases the amount of O2 which is available for non-ventilatory work. Respiratory acidosis is presented as an adaptation to an increase in the work of breathing, and it is suggested that the usual therapeutic proce-dures are effective because, directly or indirectly, they reduce the work of breathing.

This publication has 0 references indexed in Scilit: