Lal Jatin, Bhardwaj Mamta, Malik Aanchal, Bansal Teena
Department of Anaesthesiology and Critical Care, Pt. BD Sharma University of Health Sciences, Rohtak, Haryana, India.
Indian J Anaesth. 2021 Oct;65(10):738-743. doi: 10.4103/ija.ija_553_21. Epub 2021 Oct 29.
Perfusion index (PI) is a new simple, objective and non-invasive method for evaluation of the success of central neuraxial and peripheral nerve blocks. So, we conducted a study with an aim to evaluate PI as an indicator for success of ultrasound-guided supraclavicular block (SCB).
65 patients of either sex, age 18-60 years, American Society of Anesthesiologists physical status I and II posted for upper limb surgery under ultrasound (US)-guided SCB were included. PI was recorded at baseline every 2 minutes till 10 minutes and then every 5 minutes till 30 minutes after block. PI ratio was calculated as the ratio between PI at 10 minutes and baseline PI. Sensory and motor blocks were assessed at 5-minutes intervals up to 30 minutes. Descriptive analysis was applied by mean and standard deviation for quantitative, frequency and proportion for categorical variables.
Mean PI increased continuously from baseline and reached the maximum at 10 minutes and then slightly decreased up to 30 minutes, but values at subsequent time intervals were quite high as compared to baseline. In case of successful blocks, median PI started increasing 2 minutes after the block and then increased in a linear fashion till 10 minutes, whereas in case of failed blocks, it only increased minimally.
PI is an objective and faster indicator for evaluating success of US-guided SCB. A cut-off value of 3.25 for PI and 3.03 for PI ratio showed a fairly good ability with high sensitivity and specificity for predicting the success of SCB.
灌注指数（PI）是一种用于评估中枢神经轴索阻滞和周围神经阻滞成功与否的新的简单、客观且无创的方法。因此，我们开展了一项研究，旨在评估PI作为超声引导下锁骨上阻滞（SCB）成功与否的指标。
纳入65例年龄在18至60岁之间、美国麻醉医师协会身体状况分级为I级和II级、拟在超声引导下进行上肢手术的SCB患者，男女不限。在阻滞前，每隔2分钟记录一次PI，直至10分钟，然后每隔5分钟记录一次，直至阻滞30分钟后。PI比值计算为10分钟时的PI与基线PI的比值。每隔5分钟评估一次感觉和运动阻滞情况，直至30分钟。对定量变量采用均值和标准差进行描述性分析，对分类变量采用频率和比例进行描述性分析。
平均PI从基线开始持续升高，在10分钟时达到最大值，然后直至30分钟略有下降，但后续各时间点的值与基线相比仍相当高。在阻滞成功的情况下，PI中位数在阻滞后2分钟开始升高，然后呈线性升高直至10分钟，而在阻滞失败的情况下，PI仅略有升高。
PI是评估超声引导下SCB成功与否的客观且快速的指标。PI的截断值为3.25，PI比值的截断值为3.03，对预测SCB的成功具有相当好的能力，敏感性和特异性较高。
