The use of submaximal metabolic stress test derived end tidal CO2 may reflect pulmonary hypertension and need for further workup

Abstract

There is considerable interest in identifying patients with pulmonary hypertension. In a small pulmonary practice we looked at the use of end tidal CO2 (ETCO2) derived from a quick submaximal stress test and its relevance to pulmonary arterial pressures. Submaximal stress testing is much easier for patients to perform and is being increasingly used in a small office setting. We looked at patients with drops in ETCO2 on exercise and echocardiographic parameters of pulmonary hypertension.

During submaximal metabolic stress testing using Shape non-invasive medical devise, breath by breath analysis of air flow, O2 consumption and CO2 production were measured. Patients n=25 with a drop in ETCO2 (n=11) during exercise were compared to patients with a rise in ETCO2 (n=14). Echocardiographic parameters were extracted and used for analysis.

In the group of patients with a drop in ETCO2 there was a significantly higher peak right ventricular systolic pressure (p=0.013477) compared to patients with an increase in ETCO2 during exercise.

Submaximal stress testing can be easily performed in the outpatient setting. In patients being evaluated for pulmonary disease and dyspnea, submaximal stress testing may help detect patients that may benefit from further workup of pulmonary hypertension.