Value of pulse oximeter perfusion index in assessing the blocking effect of lower epidural anesthesia in elderly male patients

Abstract:

Objective：To investigate the value of pulse oximeter perfusion index（PI） in assessing the blocking effect of lower epidural anesthesia in elderly male patients. Methods：A total of 66 male patients aged ≥60 years with American Society of Anesthesiologists grade Ⅰ-Ⅲ were given 2% lidocaine via the epidural catheter and then observed for 30 minutes. The changes in PI and pain sensa－tion of the toes of both feet during needle prick and the time to the disappearance of cremasteric reflex were recorded. A PI change rate of ≥100% and the disappearance of pain sensation and cremasteric reflex were considered effective epidural blockage. A one-way analysis of variance with repeated measures was used for comparison of PI at different time points，and the chi-square test of paired fourfold data was used for comparison of the success rates of PI，cremasteric reflex，and pain measurement with needle prick in indicating epidural anesthesia at different time points. Results：PI gradually increased at 2 minutes after epidural administration and the pain with needle prick started to decrease at 4 minutes，and cremasteric reflex started to disappear at 20 minutes. At 10，20，and 30 minutes after epidural administration，all the patients achieved a 100% increase in PI（P=0.000）；0，45，and 66 patients，respec－tively，had no sense of pain during needle prick，and there was a significant increase in the number of patients from 10 to 20 min－utes（ χ2=24.973，P=0.000）；0，51，and 66 patients，respectively，had the disappearance of cremasteric reflex，and there was a signifi－cant increase in the number of patients from 10 to 20 minutes（χ2=16.923，P=0.000）. Conclusion：PI is an early and objective index of the blocking effect of lower epidural anesthesia in elderly male patients.