The Effect Of Pupillary Monitoring To Assess The Stimulation Of Visceral Pain In Propofol Anesthesia

Objective:The purpose of applying the pupil monitor is to observe the pupils of patients under propofol anesthesia for painless colonoscopy consultation,to explore the pupil changes during colonoscopy,and to assess the value and relevance of pupil monitoring for the assessment of visceral pain stimulation and depth of sedation.Methods:Ninety patients were randomly divided into control group（Group C）and intervention group（Group B）.Patients in Group C were anesthetized intravenously according to the physician’s experience and patient’s body movement,while patients in Group B were monitored according to the bispectral index（BIS）,and the BIS was maintained in the range of 40～60.The heart rate（HR）,BIS,pupillary diameter（PD）and pupillary light response velocity（PLRV）were recorded at room entry（T₁）,before post-anaesthesia colonoscopy（T₂）,at the time of colonoscopy passing through the sigmoid colon（T₃）,at the time of colonoscopy passing through the hepatic flexure of the colon（T₄）,at the end of diagnosis（T₅）and after awakening（T₆）.The number of body movements,time spent,awakening time and medication administration were recorded during diagnosis and treatment,and the rate of change（Δvalue）of pupil monitoring indexes relative to the patient’s post-anesthesia examination（T₂）was calculated.Results:There were no significant differences in gender,age,body mass index（BMI）and examination time between the two groups（P>0.05）,propofol dosage and awakening time were higher in group B patients than in group C,but patients experienced significantly fewer somatic reactions than in group C（P<0.05）.Compared with group C,BIS,PD,PLRV,ΔPD,andΔPLRV were lower in group B patients at T_4,5（P<0.05）;compared with T₂,patients in group C had higher BIS when the colonoscopy passed through the sigmoid colon and colonic hepatic flexure(T_3,4)（P<0.05）,while there was no significant difference in BIS in group B（P>0.05）;in addition,compared with T₂,the colonoscopy after T_3,4,there was no significant change in heart rate（HR）in both groups（P>0.05）,but PD and PLRV were elevated（P<0.05）.PD,PLRV were positively correlated with BIS in painless colonoscopy under intravenous anesthesia with propofol（r=0.69,0.55,P<0.05）.The critical values of BIS,PD,and PLRV for predicting patients’mid-examination somatic response were 66.50,3.25 mm,and 1.90 mm/s,respectively,and the area under the curve was 0.91（0.83～0.98）,0.93（0.87～0.99）,and0.89（0.81～0.97）.Conclusion:Pupil diameter and pupil light response rate in patients undergoing colonoscopy under intravenous anaesthesia with propofol are sensitive monitoring indicators of response to visceral pain stimulation and correlate well with depth of sedation with propofol anaesthesia.