Intraoperative bleeding is one of the main severe complications in complete video-assisted thoracoscopic surgery (c-VATS). We investigated whether one sealing device, the LigaSureV (LSV) vessel sealing system (Valleylab, Tyco Healthcare, Boulder, CO, USA) was experimentally and clinically safe and effective for c-VATS. The burst pressures (BP) of each pulmonary artery (PA) in resected lungs were measured and were compared between a thin PA group (<5 mm) and a thick PA group (> or =5 mm). To investigate the influences of the sealing situations to the adequacy of sealing, BPs were measured after dry or wet conditioned PA (soaked with 0.9% saline) were sealed and cut by the LSV. Clinically, a total of 203 PA were divided with the LSV in c-VATS. The BP of the thin PA with small diameters (<5 mm) were higher than the thick PA (607 mmHg vs. 447 mmHg; P<0.05). The sealing effect was higher when the thick PA was sealed in a dry state than in a wet state (447 mmHg vs. 399 mmHg; P<0.05). However, average BP was physiologically high enough to inhibit a burst even for thick PA sealed in a wet state. There was single case of delayed bleeding sealed PA resulted from seal contact with a sucton device. These studies demonstrated the safety and efficacy of the LSV to sealed PA in c-VATS.