[No consequences of prolonged drainage following open heart surgery on the incidence of postoperative pericardial effusion].

Pericardial effusion (PE) frequently occurs after cardiac surgery and, in some cases, complicates the postoperative course. This study was performed in order to assess if prolongation of the postoperative drainage period may result in a decreased incidence of PE. For this purpose we studied 100 patients, randomised into two groups. In group I (50 patients) standard drainage of the thorax was performed. In group II (50 patients) the drainage period was prolonged by 24 hours. The amount of fluid drained during the additional period did not correlate with preceding fluid production. Echocardiography performed on the sixth postoperative day revealed a virtually equal incidence of PE in both groups: 26 patients in group I, 29 patients in group II. None of the observed effusions resulted in clinical signs of cardiac tamponade. PE occurred more frequently in patients with more than 60 ml of additional drainage volume (p less than 0.01). We conclude that: (1) prolonging the duration of postoperative drainage does not result in a lower incidence of postoperative PE and (2) the aetiological process causing PE in a number of patients is probably already active during the early postoperative course.