Cardiac output and arterial CO2 response during intermittent positive pressure breathing with oxygen. A comparison of patients with chronic airflow obstruction and controls.

Cardiac output and arterial blood gases were studied before, during, and after intermittent positive pressure breathing, using 40% oxygen (IPPB i02). The subjects of this study were eight patients with lung disease, seven of them with chronic airflow obstruction and eight control subjects without respiratory symptoms. During IPPB/02, cardiac output was definitely lowered without a significant decrease in arterial Pco2 in the patients with airflow obstruction. Conversely, the control subjects during IPPB/02 had a large decrease in arterial Pco2 with a moderate reduction in cardiac output. Considering this response of the lung with airflow obstruction, the more frequent use of cardiac output and arterial gas measurements in patients receiving IPPB/02 treatments appears desirable. Individual cases are presented.