Effects of two chest tube clearance protocols on drainage in patients after myocardial revascularization surgery. The purpose of the study was to determine the effects of two methods of clot clearance on chest tube drainage in patients undergoing myocardial revascularization. Two hundred adult patients immediately after myocardial revascularization were randomly assigned to a specific chest tube manipulation group. The dependent variables were drainage, incidence of cardiac tamponade, incidence of surgical reentry, hemodynamic values, and number of manipulation episodes. Statistical analyses revealed no difference in any of the dependent variables when milking and stripping were used. Of the 200 patients, 78 did not require any manipulation of the chest tubes in the first 8 hours after surgery. One patient had signs of cardiac tamponade and six other patients required surgical reentry. Positioning of the connecting tube in a nondependent position assisted with the removal of drainage from the chest cavity. In conclusion, patients having myocardial revascularization did not need their chest tubes manipulated the first 8 hours after surgery. Visible drainage in the chest tube did not cause a lack of patency. 