Impact of chest tube clearance on postoperative morbidity after thoracotomy: results of a prospective, randomised trial.
OBJECTIVE
In many centres of thoracic surgery, milking of chest tubes is performed to prevent them from blocking. The usefulness of chest tube clearance is discussed controversially. Therefore, we investigated the impact of postoperative chest tube milking on postoperative outcome in a prospective, randomised trial.


METHODS
Within a period of 11 months, 145 patients undergoing pulmonary resection through thoracotomy were included in the study. Two chest tubes each (silicone drainage, Redax, Mirandola, Italy) were placed in all patients (ventral tube 21Ch and dorsal tube 24Ch). Milking was applied to both chest tubes for 1 min every 2h within the first 48 h postoperatively and continuous suction of -20 cm H(2)O was maintained for 48 h. Duration of chest tube drainage, quantity and quality of effusion or air leakage, co-morbidity, length of hospital stay and 30-day postoperative morbidity and mortality were analysed. Furthermore, outcome was measured by assessment of chest radiographs at the time of discharge from hospital.


RESULTS
Randomisation resulted in milking of chest tubes of 73 patients and in observation of chest tubes without any manipulation in 72 patients. Twenty-one patients had to be excluded from further analysis due to violation from the study protocol (n=9), necessity of replacement of a chest tubes (n=9) and re-operation for bleeding (n=3). The 30-day mortality rate was 1.4% in each group and the 30-day morbidity was 49.3% in the milking group and 52.8% in the observation group. Milking of chest tubes was not associated with a lower postoperative mortality or morbidity (p=0.99 and p=0.67, respectively; chi-square test). We observed a significant increase of postoperative pleural effusion drainage in the milking group 48 h after surgery (p=0.004; unpaired t-test). No correlation was seen between milking of chest tubes and the duration of chest tube drainage, quality of effusion, air leakage or length of hospitalisation.


CONCLUSIONS
We showed for the first time that postoperative chest tube milking is associated with a significant increase of pleural fluid drainage. Postoperative morbidity and mortality was not improved and therefore chest tube milking cannot be recommended as a routine postoperative procedure.