Atypical tamponade after cardiac operation in infants and children

A state clinically indistinguishable from cardiac tamponade can occur after operation for congenital heart disease in the absence of intrapericardial blood or clot. We have employed a method of splinting the sides of the sternum apart in nine patterns in whom low-output states developed postoperatively, unresponsive to either inotropic drugs or vasodilator therapy. Blood pressure, heart rate, central venous pressure, urine output, toe temperature, and arterial PO2 immediately before and 90 minutes after the procedure were compared. Significant increases in blood pressure (p less than 0.02), urine output (p less than 0.001), and toe temperature (p less than 0.001) and a significant fall in central venous pressure (p less than 0.001) resulted. The figures indicate a marked improvement in cardiac output which occurred without alteration in inotropic support or after load reduction. We conclude that mechanical restriction of ventricular relaxation can occur in the absence of intrapericardial blood or clot, may contribute to low-output states, and can be successfully managed by sternal splintage.