The Effect of Pulmonary Emphysema upon Cardiopulmonary Hemodynamics at Rest and During Exercise

Abstract

Thirty-three emphysematous patients with no history or clinical evidence of right ventricular failure and 20 who had been observed in right ventricular failure but had attained their maximum degree of cardiac compensation were studied at rest with measurement of right atrial and pulmonary artery pressure and cardiac output by the direct Fick principle. Pulmonary wedge pressures were obtained, and pulmonary vascular resistances were calculated in 32 of the former and 18 of the latter group. Twenty-eight of the group without failure and 16 with failure were also studied during mild exercise with measurement of the same parameters. During exercise wedge pressures were obtained, and pulmonary vascular resistances were calculated in 14 of the former and 8 of the latter group. An increased cardiac index could not be demonstrated at rest in any subject. The mean cardiac index for both groups was below that reported for normal resting man, being lower in the group with failure than in those without failure. During exercise the cardiac output increased in an essentially normal fashion in relationship to the increase in oxygen consumption in the group without failure. Hence, the value during exercise was still less than that occurring in normal subjects during comparable degrees of exercise. The group with a history of failure did not increase their cardiac output oxygen consumption ratio to the same degree as the group without failure. The mean pulmonary artery pressure was elevated in both groups at rest, being much higher in the group with failure. Pulmonary artery pressure increased to a greater degree during exercise in the group with failure than in those without failure, even though the cardiac index was less during exercise in the former group. Resting pulmonary vascular resistance was generally elevated in the group without failure and on the average did not change during exercise. The group with failure had a higher resting pulmonary vascular resistance, which rose in most subjects during exercise. Mean arterial saturation was lower at rest in the group with failure than in those without failure, and both groups demonstrated a variety of responses to exercise. Differences in present data as compared with that previously reported in emphysematous subjects are discussed and special emphasis is made concerning the difference in cardiopulmonary hemodynamics in subjects with right ventricular failure and those who had never manifested such failure.