For central lung cancer, which often involves the hilum, pneumonectomy is one of the means of treatment that has the opportunity to cure the disease, which can substantially prolong the survival time of patients [1, 11]. However, due to the high trauma of the operation, pneumonectomy is often (20–60%) followed by postoperative complications, such as low-volume circulatory disorder, pulmonary edema, pneumonia, and acute respiratory failure [2, 3, 12]. Eric Yu Wei Lo et al. concluded that compared with clamp-release drainage, balanced chest drainage results in a lower incidence of postpneumonectomy pulmonary edema and death [3]. This implies that the management of drainage tubes after pneumonectomy is very important. There is an urgent need for a simple and effective drainage method to reduce the incidence of postoperative complications after pneumonectomy. In recent years, as thoracoscopic surgery technology and the concept of ERAS have advanced, approaching pneumonectomy by minimally invasive approaches has not negatively impacted perioperative outcomes, and the incidence of complications such as empyema, mediastinal shift and major bleeding requiring reopening has decreased [12]. There is no consensus on the management of pneumonectomy postoperative drainage. Each thoracic surgery department implements its own protocol for the management of pneumonectomy postoperative drainage in clinical work. Some thoracic surgeons tend to use small-bore chest tubes after pneumonectomy, which allow for good drainage and fewer complications, and modify the chest tube management protocol from intermittent chest tube clamping to continuous open gravity drainage or even a no-drainage system [6, 13,14,15,16].

Most of the previous findings for small-bore chest tubes are applicable to patients undergoing VATS lobectomy or segmentectomy, but data for patients undergoing VATS pneumonectomy are limited [17,18,19]. Yongbin Song et al. concluded that compared with a 24-Fr chest drainage tube, the application of an 8-Fr ultrafine chest drainage tube after thoracoscopic lobectomy significantly shortened the drainage time, reduced the total drainage volume, reduced the postoperative pain degree, shortened the hospital stay, and effectively detected postoperative intrathoracic hemorrhage [8].

Although small-bore chest tubes have obvious advantages [20, 21], many people still have doubts about their application in patients undergoing pneumonectomy, such as whether the chest tube is easy to block, whether the drainage effect is good, whether it can be detected immediately when active chest bleeding occurs, and whether complications such as mediastinal shift and pulmonary edema will become more common after surgery. Our center started using a single 8.5-Fr pigtail catheter for postoperative continuous open gravity drainage after U-VATS-P in May 2016 and achieved a good drainage effect. The inner wall of the 8.5-Fr pigtail catheter has a strong anticoagulant coating and multiple drainage holes on the inner surface of the pigtail ring rather than on the side, so tube plugging rarely occurs. Every morning after the operation, the nurse squeezed the thick chest tube connecting the chest bottle to keep the 8.5-Fr pigtail catheter unobstructed by using the sudden change in pressure in the chest tube (Fig. 7b).

In this study, we retrospectively analyzed the data of 77 cases in which we used one 8.5-Fr pigtail catheter for postoperative continuous open gravity drainage after U-VATS-P. All patients received early postoperative rehabilitation, and the rate of relevant complications was low. The mean drainage volumes in the first three days after the operation were 186.31\(\pm\)50.97, 321.97\(\pm\)52.03, and 216.44\(\pm\)35.67 ml, respectively, which indicated that the 8.5-Fr pigtail catheter was very effective. Two patients had more thoracic hemorrhagic exudation after operation that could be found in time and were cured effectively after early hemostatic therapy and nutritional support, with no need for a second surgery. Three patients with chylothorax improved after receiving intravenous nutrition treatment and were extubated. During the treatment, an average total drainage volume of 2600 ml pleural effusion was drawn out through the 8.5-Fr pigtail catheter. From our clinical experience, this drainage effect is similar to that of the traditional thick chest tube [13]. In the past three years of clinical work, our center has routinely used an 8.5-Fr pigtail catheter in VATS lobectomy and conventional thoracotomy pneumonectomy, and the drainage effect has been very good.

In this study, no patient experienced life-threatening complications, such as mediastinal shift and pulmonary edema. The fluctuation range of the water column in the drainage bottle was small, within 4 cm of the water column, even when the patient coughed hard (Fig. 7c). Therefore, the 8.5-Fr pigtail catheter allows the empty hemithorax to maintain stable pressure and prevent mediastinal shifting. Because of the double fixation of the transparent adhesive dressing membrane and special drainage tube fixing sticker, no drainage tube fell off. The postoperative pain response of all patients in this study was mild, and the incision and drainage nozzle healed well.