Pupillary Monitoring To Evaluate The Effect Of Anesthesia Depth In Patients Under General Anesthesia

Objective:To explore the effect of pupillary monitoring on the evaluation of anesthesia depth in patients under general anesthesia using portable pupillometry.Methods:Sixty patients,aged from 18 to 75 years,regardless of gender and American Society of Anesthesiologists physical status（ASA）Ⅰ～Ⅲ,were included in the study.The following indexes were recorded:（1）Clinical data:age,gender,body mass index,operation duration and perioperative medication.（2）The mean arterial pressure（MAP）,heart rate（HR）,bispectral index（BIS）,pupillary diameter（PD）and pupillary light reflex velocity（PLRV）when patients entering the operating room（T₁）,before incision（T₂）,10s after incision（T₃）,30 s after incision（T₄）,1 h after incision（T₅）and at the end of the operation（T₆）.（3）Pupillary monitoring indexes in different BIS intervals.（4）The change rate of pupillary and circulatory index at each time point after skin incision were calculated[ΔT_n=（T_n-T₂）/T₂×100%],to reflect the impact of surgical stimulation on patients’physiological indexes.After the patient woke up,the verbal rating scale（VRS）was used to evaluate the patient’s pain status,and Spearman analyzed the correlation between pupillary index and the patient’s postoperative VRS score.The risk factors of VRS≥2 was analyzed by multivariate logistic regression.The area under curve（AUC）of receiver operating characteristic curve（ROC）was used in evaluating the accuracy of predicting VRS≥2 after regaining consciousness.Results:（1）General data:60 patients were included in this study,including 3 patients who used atropine during operation and 5 patients who failed to collect pupillary data.Finally,52 patients were included,26 males and 26 females;Age（48.02±17.96）years;BMI（22.45±3.66）kg/m².PD and PLRV with different BIS intervals were collected in 34patients;Pain occurred in 24 patients after awakening:17 cases were mild,6 cases were moderate and 1 case was severe.There were 6 cases of mild pain and only 1 case of moderate pain when patients leave the operating room.（2）Compared with T₂,PD at T_1,3⁶,PLRV and BIS at T₁,MAP and HR at T_1,4⁶were significantly increased（P<0.05）.Compared with T₁,ΔPD、ΔMAP、ΔHR、ΔPLRV at T_3⁶were significantly decreased（P<0.05）.Compared with T₃,ΔPD at T₆,ΔMAP at T_4,6,ΔHR at T_5⁶were significantly increased（P<0.05）.（3）There was no correlation between MAP、HR、ΔMAP、ΔHR at T₆and postoperative VRS score（P>0.05）.PD andΔPD was positively correlated with postoperative VRS score（r=0.690、0.711,P<0.05）.Logistic multivariate regression and ROC analysis showed that PD（OR:144.19,95%CI:3.25～6389.43）、ΔPD（OR:1.09,95%CI:1.02～1.16）at T₆were risk factors for VRS≥2（P<0.05）.The cut off values of PD andΔPD predicting postoperative VRS≥2 were 2.40 mm and 25.83%,respectively.The sensitivity was 0.57 and 0.96,the specificity was 0.96 and 0.78,and the area under the curve was 0.80（0.61～0.98）and 0.88（0.77～0.99）.（4）Compared with BIS<40,PD increased when BIS≥61（P<0.05）,PLRV increased when BIS≥40（P<0.05）;Compared with 40≤BIS≤60,PD increased when BIS≥61（P<0.05）,PLRV increased when BIS>80（P<0.05）;Compared with 60≤BIS≤80,PD and PLRV increased when BIS>80（P<0.05）.The PLRV and BIS of 34 patients with complete data at different time points were analyzed.It was found that BIS was positively correlated with PLRV（r=0.614,P<0.05）.Conclusion:Pupillary monitoring（especially PD）is used to monitor the depth of anesthesia in patients under general anesthesia,which can provide more timely and accurate information and provide reference for the in-depth evaluation of accurate anesthesia in perioperative period.