Clinical and Metabolic Effects of Cardiopulmonary Bypass

Abstract

The clinical and metabolic effects of cardiopulmonary bypass were stduied with fifty-three patients who underwent open heart surgery by evaluating serial laboratory examinations and clinical results. Mild anemia was a finding after extracorporeal circulations along with the thrombocytopenia followed by a platelet rebound. Hypokalemia was a characteristic of cardiopulmonary bypass being evidenced by low serum potassium levels during and after extracorporeal circulation and by the increased urinary excretion of potassium which exceeded the one of sodium in the early postoperative days. The changes of total calcium and magnesium during cardiopulmonary bypass were dependent upon their levels in the prime of oxygenator. Of serum enzymes the significant increases of SGOT and SLDH after cardiopulmonary bypass suggested various tissue injuries including thoracotomy, cardiotomy, sublethal damage to, red blood cells and hemolysis from the presence of prosthetic cardiac valves. The changes of SGPT were mild and delayed. Marked respiratory alkalosis accompanied with mild degrees of metabolic acidosis were the characteristic pattern during and early after cardiopulmonary bypass. The most common complications were the infection of sternotomy wounds. Although these were superficial in nature, they prolonged the patient's hospital stays. Disturbances of cardiac rhythms or conduction mechanisms were the next commonly seen complications and they were fatal when ventricular arrhythmias were intractable and surgical block was not treated with pacemaker implantation. There were 10 deaths, or 18.9 percent, while patients were in hospital. The hospital mortality rates among groups were 11. 2 percent (l of 9) after repairs of atrial septal septal defect, none after closure of ventricular septal defect, 26.3 percent (6 of 19) after total correction of tetralogy of Fallot and interventricular correction of double outlet right ventricle, and 28.6 percent (4 of 14) after valve replacement.