 In these patients n10 the pleura will be opened on both sides and the ventilator will be disconnected before aorta is cross-clamped and cardioplegia administered. At the end of the cardioplegic arrest, the aortic root and the LV will be actively vented and aortic cross clamp released. The time will be noted down T1. The heart will be defibrillated to sinus or pacemaker induced rhythm. The heart will be kept empty by the LV vent and ejection avoided as monitored by continual intraoperative TEE and systemic arterial pressure tracing. At 35 Celsius body temperature, as measured from the thermistor in the urinary bladder, and with apparently good cardiac contraction the de-airing will begin. Inotropic drugs or systemic arterial vasodilators will be used as and when necessary to achieve good cardiac contraction. The time will be noted down T2 T2 - T1 Pre ejection de-airing time. The LV preload will first now be successively increased by reducing the venous return from the heart-lung machine to raise CVP between 5-10 cm water. LV vent will be continuously regulated depending upon the amount of residual air showing in the left heart. When no air is seen on TEE monitoring in the left heart LA, LV Aorta, half the calculated minute ventilation with 100 oxygen and a PEEP of 5 cm H2O will be started. De-airing will be continued and when the TEE shows no or minimal air in left heart, full ventilation with unchanged PEEP will be restored. The patient will be weaned successively from the CPB thereby ensuring that entire cardiac output is diverted through the native fully ventilated lungs. When TEE will show no air in the left heart, the de-airing will be considered complete and the time noted again T3 T3 - T2 Post ejection de-airing time. 