Renal complications following heart surgery with extracorporeal circulation

Acute renal failure in the cardiovascular surgical patient

Acute renal failure is a known complication of cardiovascular surgery and is associated with a high mortality. Therapy should be aimed at prevention of oliguric renal failure, or at least its conversion to nonoliguric renal failure. Once renal failure is established, early dialysis with nutritional support probably gives the best chance for survival.

Peritoneal dialysis in infants and children after open heart surgery

Over a period of 5 years, 1975-1979, 418 infants and children were operated on for congenital cardiac malformations using cardiopulmonary bypass. Fifteen patients (4 with transposition, 4 with Fallot's tetralogy, 1 with pulmonary atresia and 6 with complex composite malformations) developed acute renal failure with anuria, which did not respond to volume load, afterload reduction, low dose dopamine, diuretics and controlled ventilation. Continuous peritoneal dialysis was started within a few hours of anuria. During dialysis the patients remained sedated, intubated and on controlled normocapnic ventilation. No complications occurred caused by the dialysis per se. Ten patients recovered and had normal serum creatinine when discharged from hospital (mean duration of dialysis: 6 days). Complex cardiac malformations were overrepresented in the 5 patients who died early in the postoperative period due to myocardial failure (mean duration of dialysis: 3 days).

Perfusate oncotic pressure during cardiopulmonary bypass. Optimum level as determined by metabolic acidosis, tissue edema, and renal function

Current practice with respect to the use of a dilutional prime for cardiopulmonary bypass (CPB) varies widely, and the safe lower limit of perfusate protein content has not been defined. We studied this question in 75 rabbits subjected to a 1-hour CPB with a perfusate colloid osmotic pressure (COP) ranging from 26 to 4 mm Hg. Metabolic acidosis was inversely related to COP; acid-base equilibrium is thus best maintained with a high perfusate protein content. Tissue edema rapidly increased at COP levels below 16 mm Hg, i.e. with a protein level less than 4.2 g%. Urinary excretion during CPB was antagonized by the COP, the reason being that glomerular filtration rate was proportional to the difference between perfusion pressure and COP. The safety margin for renal function during CPB thus widens with a decreasing perfusate protein content. We conclude that the optimum levels of perfuste oncotic pressure and protein content during experimental cardiopulmonary bypass are 16 mm Hg and 4.2 g%.