Value Of Neutrophil/Lymphocyte Ratio In Predicting Postoperative Delirium In Elderly Patients Undergoing Laparoscopic Gastrointestinal Tumor Surgery

Postoperative delirium(POD)is defined as a severe neuropsychiatric syndrome,presenting with a sudden onset,characterized by a fluctuating course of attention and accompanied by a change in cognition or perception.POD usually occurs within 7 days after surgery and is one of the common complications in elderly patients.According to statistics,the incidence of POD is as high as 13-50%in patients undergoing gastrointestinal tumor surgery.POD has a negative effect on postoperative recovery,extends the length of hospital stay,may even lead to long-term cognitive impairment and reduce the long-term survival rate and quality of life.At present,there is a lack of accurate early diagnosis and treatment methods for POD.Therefore,it is of great significance to explore early warning indicators,screen high-risk patients with delirium,diagnose and predict the development process of POD earlier.Neutrophil to lymphocyte ratio(NLR)is a new type leukocyte-derived inflammatory markers.In recent years,the relationship between NLR level and neuropsychiatric diseases has attracted more and more attention,and NLR is expected to become early predictor of POD.Objective:This study aims to analyze the risk factors of POD in elderly patients undergoing laparoscopic gastrointestinal tumor surgery,explore the correlation between perioperative NLR levels and POD,and assess the predictive value of NLR levels for POD in elderly patients.Methods:From May 2020 to September 2020,225 elderly patients who were hospitalized in our hospital and scheduled to undergo selective laparoscopic gastrointestinal tumor surgery were prospectively recruited in this study,regardless of gender,aged 65-85 years,falling into ASA physical status Ⅱ-Ⅲ.Mini-mental state examination(MMSE)was used to assess the cognitive function of patients before surgery.POD assessment was performed once a day for 7 days postoperatively by the confusion assessment method(CAM).All the patients were divided into two groups according to the assessment:POD group and Non-POD group.The patient’s preoperative general data and perioperative conditions were collected.Some laboratory test results of the patient 1 day before surgery and on the 1,3,and 5 days after surgery were recorded,including neutrophil count,lymphocyte count,C-reactive protein(CRP),etc.Then the NLR value was calculated accordingly.Univariate and multivariate Logistic regression analysis was performed to find the risk factors of POD,and receiver operating characteristic(ROC)curve analysis was used to assess the predictive value of NLR levels for POD.Results:Among the 225 patients,21 patients were illiterate or had visual or auditory impairment,4 patients had adjusted MMSE scores of less than 24,6 patients had serious postoperative complications and were transferred to the intensive care unit,and 9 patients failed to follow up after surgery.Finally,185 patients were included and POD was present in 35 patients with an incidence of 18.9%.Alcohol abuse and history of cerebral infarction could significantly increase the risk of POD(P<0.05).Preoperative levels of NLR and CRP,CRP level on the first day and NLR level on the third day after surgery were significantly higher in POD group than in NPOD group while preoperative level of hemoglobin was significantly lower in POD group than in NPOD group(P<0.05).Logistic regression analysis suggested that preoperative NLR and CRP levels were independent risk factors for POD(P<0.05).ROC curve analysis showed the area under curve(AUC)of preoperative NLR level was 0.726 at the best cut-off value of 2.225 and the sensitivity and specificity were 65.7%and 77.3%,respectively(P<0.05).The AUC of preoperative CRP level was 0.649 at the best cut-off value of 7.95 and the sensitivity and specificity were 40.0%and 96.7%,respectively(P<0.05).The AUC of preoperative NLR was greater than that of preoperative CRP.Conclusion:1.Patients with a history of alcohol abuse and cerebral infarction before surgery had an increased risk of POD;low preoperative level of hemoglobin,high preoperative levels of NLR and CRP,and high level of CRP 1 day after surgery were significantly related to the occurrence of POD.2.Higher levels of preoperative NLR and CRP were independent risk factors for POD in elderly patients undergoing laparoscopic gastrointestinal tumor surgery.3.Preoperative NLR and CRP levels in elderly patients undergoing laparoscopic gastrointestinal tumor surgery are predictors of POD,and preoperative NLR level has better predictive value.Detecting NLR level before surgery may be helpful for early prevention and diagnosis of POD.