Jain Anuj, Srinivas Sanjay, Ahmad Zainab, Kaushal Ashutosh, Kumar Harish, Waindeskar Vaishali
Department of Anesthesiology, All India Institute of Medical Sciences Bhopal, Bhopal, Madhya Pradesh, India.
Ochsner J. 2025 Summer;25(2):85-91. doi: 10.31486/toj.24.0119.
The perfusion index has previously been used to predict the success of brachial plexus blocks but to our knowledge has not yet been studied for the low interscalene block approach. This study evaluated the accuracy of the perfusion index and perfusion index ratio in predicting the success of a low interscalene brachial plexus block in patients undergoing upper limb surgery.
The study included 70 patients undergoing upper limb surgeries under ultrasound-guided low interscalene brachial plexus block. After local anesthetic injection, patients' sensory and motor blocks were assessed every 5 minutes. The perfusion index was recorded at baseline and then at 5-minute intervals until 30 minutes after anesthetic injection in both the blocked and unblocked limbs. The perfusion index ratio (perfusion index at a specific timepoint/baseline perfusion index) was calculated and recorded at each 5-minute time point. Receiver operating characteristic curves were constructed to determine the accurate value of the perfusion index that indicated block success.
The mean perfusion index and perfusion index ratio were higher in the blocked limb vs the unblocked limb at all time points. At the 10-minute time point, the cutoff values for the perfusion index and perfusion index ratio for a successful block were 3.24 and 3.54, respectively. At the 10-minute time point, the sensitivities of the perfusion index and perfusion index ratio in predicting a successful block were 95.2% and 100%, respectively; specificity was 100% for both the perfusion index and perfusion index ratio.
The perfusion index and perfusion index ratio can accurately predict the success of a low interscalene brachial plexus block well before surgical anesthesia is fully established, thereby saving operating room time. A perfusion index ratio of 3.54 or more at 10 minutes is a reliable predictor of block success.
灌注指数此前已被用于预测臂丛神经阻滞的成功率，但据我们所知，尚未针对低位肌间沟阻滞法进行研究。本研究评估了灌注指数和灌注指数比在预测接受上肢手术患者低位肌间沟臂丛神经阻滞成功率方面的准确性。
本研究纳入了70例在超声引导下接受低位肌间沟臂丛神经阻滞的上肢手术患者。局部麻醉药注射后，每5分钟评估患者的感觉和运动阻滞情况。在基线时记录灌注指数，然后在麻醉药注射后每隔5分钟记录一次，直至30分钟，记录部位包括阻滞侧和未阻滞侧肢体。计算并记录每个5分钟时间点的灌注指数比（特定时间点的灌注指数/基线灌注指数）。构建受试者工作特征曲线以确定表明阻滞成功的灌注指数准确值。
在所有时间点，阻滞侧肢体的平均灌注指数和灌注指数比均高于未阻滞侧肢体。在10分钟时间点，成功阻滞的灌注指数和灌注指数比的截断值分别为3.24和3.54。在10分钟时间点，灌注指数和灌注指数比预测成功阻滞的敏感性分别为95.2%和100%；灌注指数和灌注指数比的特异性均为100%。
灌注指数和灌注指数比能够在手术麻醉完全建立之前准确预测低位肌间沟臂丛神经阻滞的成功率，从而节省手术室时间。10分钟时灌注指数比达到3.54或更高是阻滞成功的可靠预测指标。
