STUDY OBJECTIVES: To evaluate the safety and efficacy of smaller-caliber drains in patients undergoing open heart surgery. DESIGN: A retrospective analysis of the medical records and chest radiographs assembled data on total amount of drainage, number of days of drainage, length of postoperative stay, appearance of postoperative chest radiographs, and need for further drainage from either the pleural or pericardial spaces. SETTING: A large university-based teaching hospital, where > 800 open-heart procedures are performed yearly. PATIENTS AND INTERVENTIONS: A total of 202 patients underwent standard open heart surgery by one surgeon, and postoperative pleural and pericardial decompression was undertaken using small caliber, more flexible drains connected to bulb suction. RESULTS: Tubes were left in an average of 2.4 days, with a mean of 826.7 mL collected during that time. The average postoperative length of stay was 6.7 days (median, 5 days). At or before 6-week follow-up, chest radiographs revealed moderate or large effusions in 19 patients (9.4%) in a pleural space that had been drained postoperatively. Twelve patients (5.9%) required an additional postoperative procedure for pleural drainage (eight thoracenteses, four tube thoracostomies). Four patients (2.0%) required reexploration of the pericardium for tamponade. CONCLUSIONS: Use of smaller-caliber drains have been found at our institution to be an adequate means of decompression of the pleural and pericardial spaces following open heart surgery, with patients rarely having clinically significant pleural effusions at 6-week follow-up.