Intraoperative Oxygen Concentration and Postoperative Delirium After Laparoscopic Gastric and Colorectal Malignancies Surgery: A Randomized, Double-Blind, Controlled Trial
Xu Lin, Pei Wang, Ding-Wei Liu, Yuwei Guo, Chun-Hui Xie, Bin Wang, Rui Dong, Lixin Sun, Mingshan Wang, Yanlin Bi
Abstract
Purpose: Postoperative delirium (POD) is common in elderly patients undergoing laparoscopic surgery for gastric and colorectal malignancies. POD may be affected by different fraction of inspired oxygen (FiO 2 ). The purpose of this study was to compare the effects of different FiO 2 on POD. Patients and Methods: A randomized, double-blind controlled trial was performed in Qingdao Municipal Hospital Affiliated to Qingdao University. A total of 662 patients aged 65 to 85 years old underwent isolated laparoscopic radical gastrectomy, radical resection of colon cancer, or radical resection of rectal cancer only. A random number table method was used to divide the patients into two groups: 40% FiO 2 (group A) and 80% FiO 2 (group B). The primary endpoint was the incidence of POD, which was assessed by the Confusion Assessment Method (CAM) twice daily during the first 7 postoperative days, and POD severity was measured by the Memorial Delirium Assessment Scale (MDAS). The secondary endpoints were the intraoperative regional cerebral oxygen saturation (rSO 2 ), Bispectral (BIS) index, invasive arterial blood pressure (IABP), oxygen saturation (SpO 2 ), end-tidal carbon dioxide partial pressure (P ET CO 2 ), the number of atelectasis cases and visual analogue scale (VAS) scores on days 1– 7 after surgery. Results: The incidence of POD was 19.37% (122/630), including 20.38% (64/314) in group A and 18.35% (58/316) in group B. No statistical significance was found in the incidence of POD between the two groups ( P > 0.05); compared with group B, SpO 2 , rSO 2 and PaO 2 decreased at T 2 to T 4 time point ( P < 0.01), and the incidence of postoperative atelectasis decreased ( P < 0.05) in group A. Conclusion: The incidence of POD was not significantly affected by different FiO 2 and the incidence of postoperative atelectasis was decreased at low FiO 2 . Keywords: intraoperative oxygen concentration, postoperative delirium, malignancy