Comparison of Postoperative Small-bore Pigtail or Large-bore Chest Tube Placement After Uniportal Video-assisted Thoracoscopic Surgery for Postoperative Analgesia and Enhanced Recovery: a Randomized Controlled Trial.

Design A randomized controlled trial.

Setting The uniportal VATS has a small linear wound about 3 to 5 cm at only one intercostal space, mostly 4th or 5th. After elective thoracic surgery, the investigators routinely placed either one 14-Fr pigtail catheter or one 20-Fr chest tube for postoperative drainage.

The patients regularly receive thoracoscopic internal costal nerve block with 10 mL of 1% Ropivacaine at the end of the operation, and are routinely prescribed with oral Tramadol 37.5mg and Acetaminophen 325mg four times a day postoperatively and intravenous morphine as extra dose if need. The investigators check chest X ray on postoperative day one and try to remove the drainage tube soon if well lung expansion and ambulation without adverse events. Then the investigators will discharge this patient six hours later or the next day after drain removal smoothly.

Sample size determination and statistical analysis The patient number in one group will be calculated on the basis of significant pain relief and set as 33 patients with the following statistic parameter: α: 0.05 (type I error probability), power 0.8 (probability of correctly rejecting the null hypothesis), δ: 0.5 (difference in population means), σ: 1 (standard deviation of difference). The investigators added 20 % noncompliance rate and forty patients in each group (total eighty patients) will be included in this study.

Participants The investigators enrolled eighty consecutive adult patients, over 20 years old, undergoing elective uniportal VATS lung resection, pleural tumor removal or mediastinal lymph node biopsy, etc. The exclusion criteria are patient refusal, body mass index > 27 kg/m2, American society of anesthesiologists (ASA) grade above 3, contraindication to nerve block, allergy to analgesic agents, regular opioid used for chronic pain prior to this time surgery, anticipating postoperative patient control analgesia (PCA) before operation, surgeon's decision for exclusion during operation, conversion to thoracotomy or multiportal VATS procedure, postoperative intubation, postoperative intensive care unit admission.