During ventilation, the lungs may serve as accessory pumps for forward blood flow. We have noted significant hemodynamic improvement in several patients during short periods of vigorous hand ventilation with the Ambu bag and tried to reproduce the hemodynamic improvement in the management of four patients with profound low cardiac output syndrome secondary to right ventricular (RV) failure following open heart surgery. High frequency, high volume (HFHV) ventilation resulted in improved hemodynamics in these patients, as evidenced by pulsatile pulmonary blood flow and increased cardiac output. Right-sided stroke work was present and there was a fall in mean central venous pressure (CVP) and rise in mean pulmonary artery pressure (PAP).