Correlation Between Peripheral Perfusion Index And Cardiovascular Response After Tracheal Intubation

Objective:To clarify the correlation between the change rate of Perfusion index（PI）under electrical stimulation before endotracheal intubation and the cardiovascular response after endotracheal intubation,explore the cut-off value of PI change rate of cardiovascular positive response after endotracheal intubation,and provide reference for the use of PI change rate to guide the selection of tracheal intubation timing during anesthesia induction.Methods:A total of 100 patients,aged 18–60,who underwent elective lithotripsy of urinary stones in a hospital from December 2021 to June 2022 were selected.Do not use any pre-anesthesia drugs before the operation.Open the vein channel,connect the relevant monitoring equipment,and monitor the mean arterial pressure（MAP）,heart rate（HR）,pulse oxygen saturation（Sp O₂）,PI,temperature（TEMP）,muscle relaxation index,and Narcotrend sedation index under local anesthesia.Use midazolam（2 mg）,fentanyl（4μg/kg）,etomidate（0.3 mg/kg）,and then use rocuronium（0.9 mg/kg）was given to the patient after the disappearance of the eyelash reflex,and the respirator was used to control the breathing.The stimulator was used to apply an electrical stimulation at 2minutes and 30 seconds after the induction,and the visual laryngoscope was used to guide the tracheal intubation at 30 seconds after the stimulation.After the intubation,the breathing was controlled and the changes in vital signs were observed.Record the PI,MAP,HR and other data at the time of entry（T₀）,after midazolam sedation（T₁）,after induction（T₂）,before stimulation（T₃）,after stimulation（T₄）,at intubation（T₅）,10s after intubation（T₆）,30s after intubation（T₇）,1min after intubation（T₈）,and 3min after intubation（T₉）,and record the occurrence of cardiovascular reactions.Logistic regression was used to analyze the impact of different indicators on the outcome during the induction process,and Pearson correlation analysis was performed on the PI value,PI change rate,and cardiovascular response after intubation at different times.The receiver operating characteristic curve（ROC）was drawn,and the area under the curve（AUC）and cutoff value were calculated.Results:The patients were divided into two groups based on the fluctuation of blood flow after intubation:positive and negative cardiovascular reactions.There was no significant difference between the two groups in gender,age,height,weight,and body temperature（P>0.05）.There was no significant difference in MAP,HR,PI,TEMP,NTI between the two groups at T₂ after using midazolam sedation（P>0.05）.During induction,MAP,HR,PI,and NTI were compared between the two groups,and it was found that there was no significant difference between the two groups.The comparison between different time points found that there were significant changes over time.When comparing each moment separately,MAP is only different at T₇ and T₈,HR is only different at T₅ and T₇,PI is not significantly different at each moment,NTI is different at T₁.There are no difference at other moments.The results showed that MAP,HR and NTI had no effect on the outcome（P>0.05）,but the influence of the PI change rate on the cardiovascular response after intubation was statistically different（OR=1.423,95%CI=（1.210-1.674）,P<0.05）.Compare the PI value of T₁,T₂,T₃,T₅,and the PI change rate of T₅/T₁,T₅/T₂,T₅/T₃,T₄/T₃ with the cardiovascular response after intubation.The results show that the PI value at each time,the PI change rate of T₅/T₁,T₅/T₂,T₅/T₃ were not correlated with the cardiovascular response after intubation,and the PI change rate of T₄/T₃ is positively correlated with the cardiovascular response after intubation,r=0.458,P<0.001.Draw the ROC curve of T₄/T₃ PI change rate and cardiovascular response after endotracheal intubation and calculate its AUC=0.835,95%CI is 0.746～0.923,the maximum Jordan index is 0.569,and the cutoff value is 8.6%.At this time,the sensitivity is 83.3%and the specificity is 73.5%.Conclusion:This study confirmed that the PI change rate under appropriate stimulation before endotracheal intubation is positively correlated with the cardiovascular response after endotracheal intubation,and when the PI change amplitude before and after stimulation is less than 8.6%,the probability of cardiovascular positive reaction after endotracheal intubation is small.