Comparison of the efficacy of five different objective methods to evaluate the success of infraclavicular block; which one of them is a reliable and early indicator?

Background: Traditional methods that evaluate the success of peripheral nerve block have been replaced by methods that allow objective evaluations over time. Multiple objective techniques for peripheral nerve block have been discussed in the literature. This study aims to investigate whether perfusion index (PI), non-invasive tissue hemoglobin monitoring (SpHb), tissue oxygen saturation (StO2), tissue hemoglobin index (THI), and body temperature are reliable and objective methods to evaluate the adequacy of infracla-vicular blockage.

Methods: Ultrasound-guided infraclavicular block in 100 patients undergoing forearm surgery. PI, SpHb, StO2, THI, and body tem-perature measurements was recorded 5 min before the block procedure, right after the procedure, and until the 25th min after the procedure at 5-min intervals. These values were compared between the blocked limbs and non-blocked limbs while being statistically compared between the successful and failed block groups.

Results: Although there were significant differences between the groups of blocked extremity and non-blocked extremity in terms of StO2, THI, PI, and body temperature, there was no significant difference between these groups in terms of SpHb. Moreover, a sig-nificant difference was detected between the groups of successful block and failed block in terms of StO2, PI and body temperature, while there was no significant difference between these groups in terms of THI and SpHb.

Conclusion: StO2, PI, and body temperature measurements are the simple, objective, and non-invasive techniques to be used to evaluate success of block procedures. According to the receiver operating characteristic analysis, StO2 is the specific parameter with the highest sensitivity among these parameters.