Cardiorespiratory effects of protamine after cardiopulmonary bypass in man.

, , 534-538. The cardiorespiratory changes following the injection of protamine sulphate (6 mg/kg) were studied in 15 patients who had undergone cardiopulmonary bypass. There was a transient fall in arterial pressure and a more prolonged increase in pulmonary artery pressure. There was a significant fall in arterial oxygen tension which was mainly due to a reduction in mixed venous oxygen tension resulting from a fall in cardiac output. Dead space/tidal volume ratio and percentage shunt did not change significantly.