Uppal V, Sondekoppam R V, Dhir S, Mackinnon S P, Kwofie M K, Retter S, Lopera L M, Szerb J J, McKeen D M
Department of Anesthesia, Peri-operative Medicine and Pain Management, Dalhousie University, Nova Scotia Health Authority and IWK Health Centre, Halifax, NS, Canada.
Department of Anesthesia, University of Iowa, Iowa City, IA, USA.
Anaesthesia. 2019 Dec 3. doi: 10.1111/anae.14939.
The objective of this study was to evaluate whether the failure rate of ultrasound-guided axillary brachial plexus block is similar in obese patients compared with non-obese patients when performed as the primary anaesthetic technique. We recruited 105 obese (body mass index ≥ 30 kg.m ) and 144 non-obese patients to this prospective, observational, cohort study conducted at two Canadian centres. A perineural technique of axillary brachial plexus block was performed using 30 ml ropivacaine 0.5% under real-time ultrasound guidance. Sensory and motor block assessment was carried out every 5 min until 30 min after block completion in all four terminal nerve distributions (radial, median, ulnar and musculocutaneous nerve). A composite score consisting of three sensory points and three motor points was used for assessment in each nerve distribution. A failed block was defined as a score of less than 14 points out of a possible 16 points, or a sensory block score less than 7 out of 8 points 30 min after block completion. Thirty minutes after block completion, obese patients had a higher failure rate of 33.7% (34/101) compared with 17.8% (24/135) for non-obese patients, with a failure rate difference (95%CI) of 15.9% (6.4-27.1%) between the groups. The median (IQR [range]) time to achieve a successful block in obese patients was 25 (20-30 [5-30]) min, compared with non-obese patients at 20 (15-30 [5-30]) min (p = 0.003). Despite a higher sensory-motor failure rate as per the composite score, the axillary brachial plexus block provided adequate surgical anaesthesia as indicated by a low need for conversion to general anaesthetic in obese (8.6%) and non-obese patients (7.0%; p = 0.656). This study showed that despite ultrasound guidance, obese patients had a slower onset time and higher axillary brachial plexus block failure rate at 30 min compared with non-obese patients.
本研究的目的是评估超声引导下腋路臂丛神经阻滞作为主要麻醉技术时，肥胖患者与非肥胖患者的失败率是否相似。我们招募了105名肥胖（体重指数≥30kg/m²）患者和144名非肥胖患者，参与在加拿大两个中心进行的这项前瞻性观察性队列研究。在实时超声引导下，采用神经周围技术，使用30ml 0.5%的罗哌卡因进行腋路臂丛神经阻滞。在所有四条终末神经分布（桡神经、正中神经、尺神经和肌皮神经）中，每隔5分钟进行一次感觉和运动阻滞评估，直至阻滞完成后30分钟。在每条神经分布中，使用由三个感觉点和三个运动点组成的综合评分进行评估。阻滞失败定义为在可能的16分中得分低于14分，或在阻滞完成后30分钟时感觉阻滞得分低于8分中的7分。阻滞完成后30分钟时，肥胖患者的失败率较高，为33.7%（34/101），而非肥胖患者为17.8%（24/135），两组之间的失败率差异（95%CI）为15.9%（6.4 - 27.1%）。肥胖患者成功阻滞的中位（IQR[范围]）时间为25（20 - 30[5 - 30]）分钟，而非肥胖患者为20（15 - 30[5 - 30]）分钟（p = 0.003）。尽管根据综合评分感觉运动失败率较高，但腋路臂丛神经阻滞在肥胖（8.6%）和非肥胖患者（7.0%；p = 0.656）中转为全身麻醉的需求较低，表明提供了足够的手术麻醉。这项研究表明，尽管有超声引导，但与非肥胖患者相比，肥胖患者在30分钟时起效时间较慢且腋路臂丛神经阻滞失败率较高。
