Impact of obesity on the incidence of postoperative pulmonary complications following laparoscopic colorectal surgery

Abstract

Objective: To evaluate the effects of obesity on the incidence of postoperative pulmonary complications (PPCs) following laparoscopic colorectal surgery. Methods: A total of 150 patients with pathological diagnosis of colorectal cancer who accepted laparoscopic colorectal excision from January to May 2023 were retrospectively recruited. All the patients scored 26 points or more in the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) model, making them all in intermediate to high risks of PPCs. Patients were divided into obesity group and non-obesity group depending on whether they were obese or not. Propensity score matching (1∶1) was performed to achieve the balance of clinicopathological characteristics with the matching factors of age, sex, respiratory complications and ARISCAT score. A total of 96 patients were eventually enrolled, with 48 patients in obesity group and 48 patients in non-obesity group. Besides, the patients were divided into 25°-30° Trendelenburg subgroup and ±10°-15° Trendelenburg subgroup according to surgical sites for further analysis. The incidence of PPCs, the intraoperative airway pressure and blood biomarker expression of lung injury, including soluble receptor for advanced glycation end products (sRAGE) and angiopoietin-2 (ANG2) at postoperative day (POD) 1 and POD3 between the two groups were compared. The relationship between obesity and incidence of PPCs within 30 postoperative days were analyzed with unifactorial Cox proportional hazard model. Results: The obesity group was comprised of 35 males and 13 females with a median age of 60 (49, 69) years, and the non-obesity group was comprised of 35 males and 13 females with a median age of 60 (52, 67) years. The incidence of PPCs was 50.0% (24/48) in the obesity group, which was higher than 20.8% (10/48) in the non-obesity group and the incidence of grade Ⅰ PPCs and microatelectasis were 31.3% (15/48) and 33.3% (16/48), higher than the 12.5% (6/48) and 12.5% (6/48) of the non-obesity group (all P<0.05). The peak airway pressure (Ppeak) and plateau airway pressure (Pplat) of patients in obesity group were 34.0(31.5, 36.5) and 30.0(27.0, 32.0) cmH2O(1 cmH2O=0.098 kPa), which were significantly higher than the 26.0 (24.0, 29.5) and 22.0 (21.0, 26.5) cmH2O of the non-obesity group (all P<0.001). The ANG2 level of the obesity group at POD3 was 11.9 (8.4, 16.5) μg/L, which was higher than 9.2 (6.0, 12.3) μg/L of the non-obesity group (P=0.045). In 25°-30°Trendelenburg subgroup, the incidence of PPCs in obese patients were significantly higher than that of non-obese patients [41.4% (12/29) vs 11.4% (4/35), P=0.005]. In ±10°-15°Trendelenburg subgroup, no significant difference was found in PPCs incidence between obese and non-obese patients [63.2% (12/19) vs 46.2% (6/13), P=0.215]. The unifactorial Cox proportional hazard model analysis showed that obesity was a risk factor of PPCs in 30 postoperative days (HR=3.015, 95%CI: 1.438-6.321, P=0.001). Conclusion: In patients undergoing laparoscopic colorectal surgery with intermediate to high risk of PPCs, obesity raises intraoperative airway pressure and aggravates intraoperative lung endothelial injury. Obesity is a risk factor of PPCs in 30 postoperative days.