Objective To explore the value of perioperative neutrophil to lymphocyte ratio (NLR) in predicting postoperative delirium (POD) of elderly patients with gastrointestinal tumor surgery.

Methods A total of 185 elderly patients with selective laparoscopic surgery for gastrointestinal tumors were selected. Before surgery, the patient′s cognitive function was evaluated by the Mini-Mental State Examination (MMSE); from the first day to the seventh day after surgery, the incidence of POD in patients was evaluated by the Confusion Assessment Method (CAM), and they were divided into POD group and NPOD group. The general materials of the patients before surgery, perioperative conditions, and partial laboratory examination resultsneutrophil count, lymphocyte count and C-reactive protein (CRP)at 1 day before surgery and 1 day, 3 and 5 days after surgery were recorded, and the NLR value was calculated. The predictive value of NLR for POD was analyzed by multiple factor Logistic regression analysis and receiver operating characteristic (ROC) curve.

Results Among the 185 patients, 35 patients had POD, and patients with histories of smoking and cerebral infarction had an increased risk of delirium (P < 0.05). The preoperative NLR and CRP levels in the POD group were significantly higher than those in the NPOD group, the preoperative hemoglobin level was significantly lower than that in the NPOD group, and the CRP level at 1 day after operation and the NLR level at 3 days after operation were significantly higher than those in the NPOD group (P < 0.05). Multi-factor Logistic regression analysis showed that preoperative NLR and CRP levels were the independent risk factors for the occurrence of POD (P < 0.05). ROC curve analysis showed that the area under the curve (AUC) of preoperative NLR level for predicting POD was 0.726, with the optimal critical value of 2.225, sensitivity of 65.7% and specificity of 77.3%; the AUC of preoperative CRP level for predicting POD was 0.649, with the optimal critical value of 7.95 mg/L, sensitivity of 40.0% and specificity of 96.7%; the AUC of preoperative NLR for predicting POD was greater than that of CRP.

Conclusion Preoperative NLR and CRP levels are the predictive indicators for POD in elderly patients with laparoscopic surgery for gastrointestinal tumors, and preoperative NLR level has better predictive value. Preoperative detection of NLR level has certain value for early prevention and diagnosis of POD.