The total carbonate content of the arterial and venous plasma in patients with chronic pulmonary emphysema

Abstract

This study represents six determinations of the total carbon dioxide content of the arterial and venous plasma over a period of six months on three patients with chronic pulmonary emphysema of the so-called “large lunged” type. The patients were males between forty-five and fifty years of age with definite enlargements in all diameters of the thorax, particularly the anterior-posterior diameter; thus presenting the typical “barrel shaped” chest. They were singularly free from cardio-renal disease so that all their symptoms and signs were attributed to the disturbance in the respiration resulting from the degenerative process in the lung. From observations to be reported in detail elsewhere, it has been found that this type of patient will tolerate an unusually high percentage of CO₂ in the inspired air with little increase in the minute volume over that at room air and without any subjective symptoms of distress. As a rule such patients breath eight to ten per cent. CO₂ for from ten to fifteen minutes with no apparent discomfort. That is, one man who has been under observation for the past nine months had a respiratory rate of twenty-two and a minute volume of ten liters while breathing room air. During an experiment in which air containing 11.4 per cent. CO₂ was inspired for a period of six minutes, the respiratory rate remained at twenty-two and the minute volume increased to only fourteen liters. At this high concentration of inspired CO₂ the patient complained of a little dizziness and nausea which disappeared when he was allowed to breath room air for a few minutes.

In an attempt to explain the unusual tolerance to CO₂ in the inspired air shown by the type of case described, the CO₂ content of the arterial and venous plasma of three patients have been determined and found to be consistently above normal as indicated by the data in the accompanying table.