Analysis of the Respiratory Response to Carbon Dioxide Inhalation in Varying Clinical States of Hypercapnia, Anoxia, and Acid-Base Derangement

Abstract

Individuals with cor pulmonale secondary to chronic pulmonary emphysema tend to have pulmonary ventilation which is less than normal both at rest and during exercise, despite the presence of factors ordinarily making for increased ventilation such as anoxemia and acidosis (1), and despite the fact that these ventilatory levels may be appreciably less than the observed maximum breathing capacity. Moreover, the ventilatory response to increased CO2 in the inspired air may be less than normal in certain patients with pulmonary emphysema (2-5). These observations have been interpreted as indicating a disorder of the chemical regulation of respiration associated with emphysema.

Observations on Carbon Dioxide Tension During Recovery From Metabolic Acidosis1

“…The opposite response, decreased sensitivity to pCO2, has been adequately demonstrated in chronic hypercapnic states (22)(23)(24)(25).…”

Gas Exchange in Severe Chronic Obstructive Lung Disease in Relation to Inspired Oxygen and Increased Carbon Dioxide Fraction, Physical Exercise and Body Posture

“…The role of the haemoglobin concentration in the ventilatory regulation might not in general be as important (1) as in a few cases in this material. The individual findings indicating that deviating haemoglobin concentration (either low or high) are associated with ventilatory changes can hardly be coincidental though the number of these cases is small.…”

“…Note that all patients are not included as not all of them were capable of continuing the work test until the periods concerned Table VIII. Comparison of pulmonary gas exchange, arterial blood gas tensions, acid-base balance, oxygen saturation and lactate at the same work load: 1 ) in the supineposture between the periods 3-6 rnin and 8-10 min, and2) in the sitting posture between the periods 3-6 and 12-15 rnin and between 12-15 and 27-30 min in those R -and C-group patients who breathed through a respiratory valve and thus made gas exchange studies possible The mean differences and S.E.M., as well as the degrees of statistical significance are given as in Table VII or, in some patients, gas exchange studies could not be combined with exercising. The work load was 167 f 17 kpm/min in the Rgroup male patients and 91 k 14 kpm/min in the R-group female patients.…”

Modification of the Respiratory Response to Carbon Dioxide by Salicylate

“…In the normal subject a steady state as determined by consistency of respiratory quotient values, pulmonary ventilation, and respiratory frequency is obtained only after 25 to 30 minutes of uninterrupted breathing of a carbon dioxide gas mixture in the concentrations used (3,4). Therefore, expired gas was collected during the last three minutes of 26 to 33-minute periods of continuous inhalation of the two CO, mixtures.…”

“…It is well known that CO2 inhalation is associated with increased ventilation in normal man, and the sensitivity of the nervous regulatory mechanism to this physiological stimulus has been reasonably well defined (1)(2)(3). Likewise the clinical entity of hyperventilation associated with salicylate toxicity has long been recognized.…”