Correlation Between Pupillary Light Reflex And Recovery Time And Postoperative Delirium In Elderly Patients After General Anesthesia

PURPOSEWe try to find out the correlation between the parameters of the pupillary light reflex and recovery time after general anesthesia and postoperative delirium in aged patients,and to test the predictive value of the parameters of the pupillary light reflex for delayed emergence from anesthesia and postoperative delirium.METHODS1.60 elderly patients(≥65 years old)who underwent spinal surgery in the Second Affiliated Hospital of Nanchang University from July 2021 to February 2022 were selected.The contraction rate and contraction velocity of pupillary light reflex were measured 1 day before the operation,and the Mini-mental State Examination(MMSE)score was recorded.2.Determine a unified induction and maintenance program of general anesthesia.Induction: midazolam 0.02 mg / kg + sufentanil 0.2ug / kg + etomidate 0.3mg / kg +rocuronium 0.9mg/kg+dexamethasone 5mg.Maintenance: propofol 4-12 mg /(kg*h)+ sevoflurane 2%+ cisatracurium 0.1mg/(kg*h),adjust propofol and sevoflurane to maintain BIS 40-60.Sufentanil 5-10 ug was added when the analgesia was insufficient.3.Record the additional dosage of sufentanil during operation,the duration of operation,intraoperative bleeding volume,the contraction rate,and velocity of pupillary light reflex immediately after drug withdrawal.4.The recovery time from anesthesia was recorded,and the scores of MMSE and Confusion Assessment Method-Chinese revision(CAM-CR)were recorded on the 3rd and 7th days after the operation.5.According to the postoperative recovery time,the patients were divided into delayed emergence from anesthesia group and non-delayed emergence from anesthesia group and were divided into the delirium group and non-delirium group according to the postoperative CAM-CR scores.6.we analyzed the correlation between pupillary light reflex parameters and recovery time,and MMSE and CAM-CR score,then compared the differences in pupillary light reflex parameters between delayed emergence from anesthesia group and non-delayed group,delirium group,and non-delirium group.Drew receiver operating characteristic(ROC)curve,and calculate the area under ROC curve(AUC)to evaluate the accuracy of pupillary light reflex parameters as a predictor of postoperative delirium.RESULTS1.17%(10/60)of the patients had delayed emergence from anesthesia.20% of the patients were diagnosed with postoperative delirium by CAM-CR score,most of them(75%)were diagnosed on the 3rd day after the operation,25%(3/12)were diagnosed on the 7th day after the operation,and only 1 patient was diagnosed with postoperative delirium in both evaluations.2.The correlation between pupillary light reflex parameters and recovery time was not statistically significant(P>0.05),and the difference in pupillary light reflex parameters between delayed emergence from anesthesia group and non-delayed group was not statistically significant(P>0.05).3.The cognitive function of the patients decreased on the 3rd day after the operation,but most of them recovered on the 7th day after the operation(P<0.05).4.The contraction rate and velocity of pupillary light reflex measured immediately after operation were lower than those before operation(P<0.05)and correlated with MMSE and CAM-CR scores on the 3rd day after the operation(P<0.05),and the contraction rate and velocity of pupil light reflex in the delirium group were lower than those in the non-delirium group(P<0.05).5.The AUC of contraction rate of pupillary light reflex for predicting postoperative delirium is 0.679(0.499 to 0.858;P=0.57),and the AUC of the contraction velocity of pupillary light reflex is 0.718(0.560 to 0.870;P=0.02).When the cut-off value is 2.336mm/s,the contraction velocity of pupillary light reflex shows the best predictive value(sensitivity 62.50%,specificity 74.78%).CONCLUSIONWe did not found that the parameters of pupillary light reflex were correlated to the delayed emergence from anesthesia in this study;the cognitive function of elderly patients decreased after anesthesia and operation,and the contraction rate and velocity of pupillary light reflex were correlated with MMSE and CAM-CR scores.Compared with non-delirium patients,the contraction rate and velocity of pupillary light reflex of delirium patients were decreased.Contraction velocity of pupillary light reflex can be used as a predictor of postoperative delirium.In contrast,contraction rate as a predictor of delirium may not be statistically significant.