Abstract: Objective To investigate the influence of low oxygen concentration (30%) and high oxygen concentration (80%) on postoperative pulmonary complications(PPCs) in the elderly patients undergoing laparoscopic radical colonectomy. Methods A total of 120 patients aged 65-80 years old who underwent laparoscopic radical resection of colon cancer were selected, with an American Society of Anesthesiologists gradeⅠ-Ⅱ and the expected operation time was more than 1 h. The patients were randomly divided into 30% fraction of inspiration oxygen (FiO₂) group (L group) and 80% FiO₂ group (H group). The incidence and the severity of PPCs of the two groups 7 days after operation was recorded and compared, as well as the intraoperative fluid infusion volume and blood loss, duration of surgery and anesthesia, dosage of analgesics, incidence of postoperative nausea and vomiting, and length of hospital stay. Results The incidence rate of PPCs, including lung infection, atelectasis, pleural effusion, pneumothorax and respiratory failure, was not significantly different between the two groups (P> 0.05). The incidence rate of PPCs with grade 2 and above in L group was significantly lower than that in H group(P＜0.05). There were no significant differences in the intraoperative fluid infusion volume, blood loss, duration of surgey, dosage of analgesics, hospital stay and other adverse reactions. Conclusions 30% FiO₂ and 80% FiO₂ show no different influence on the occurrence of PPCs in the elderly patients undergoing elective laparoscopic radical colonectomy, but 30% oxygen concentration can reduce the severity of PPCs.

Key words: inhaled oxygen concentration, aged, postoperative pulmonary complications