Oscillatory cardiopulmonary effects of high-frequency jet ventilation

The cardiovascular effects of high-frequency jet ventilation (HFJV) were compared with conventional volume ventilation in the anesthetized dog. A unique effect of HFJV on stroke volume and cardiac output was observed when stroke volume was analyzed on a beat-by-beat basis with impedance cardiography. A pronounced amplitude modulation of stroke volume, as well as of pulmonary and arterial pressure, occurred when the frequency of the HFJV approached the heart rate. The beat frequency of these amplitude oscillations was equal to that predicted based upon the frequency of the HFJV and the heart rate. Cardiac outputs obtained by techniques which average several beats will not detect these oscillations in cardiac output. These findings suggest that HFJV can generate an oscillation in thoracic hemodynamics which affects ventricular output in a similar manner.