The Study Of Ultrasound-guided Supraclavicular Brachial Plexus Block

Objective In recent years, the methods of nerve block have fundamentally innovated with the development of ultrasound technology. Compared with traditional methods, ultrasound-guided supraclavicular brachial plexus block already has its unique clinical advantages. The aim of this study was to research the relationship between the supraclavicular brachial plexus and the tissue around it under the high-resolution sonography, to offer relevant anatomical variants to further optimize the application of ultrasound-guided technique. Meanwhile, we compared the clinical effects of supraclavicular brachial plexus block guided by ultrasound (single-injection, three-injection with different dose) with that guided by anatomical landmarks, in order to provide some references for clinical application of ultrasound-guided supraclavicular brachial plexus block.Methods Part one: 30 patients scheduled for upper extremity operation and 170 common patients were recruited. We gained the optimum transversal ultrasound image of supraclavicular brachial plexus (SBP) and subclavian artery (SA) through a portable ultrasound systems with a linear 6～13 MHz transducer. We measured the included angle between the skin line and the SBP-to-SA centre line, the distance of SBP-to-SA, the distance of skin-to-SA, skin-to-first rib and skin-to-SBP with ultrasound workstation (V1.3). The patients scheduled for upper extremity operation were blocked under ultrasound guidance. Part two: 150 patients scheduled for upper extremity operation were randomly divided into five groups: Group A (21ml single-injection), Group B (7ml three-injection), Group C (6ml three-injection), Group D (5ml three-injection), and Group E (21ml injection by anatomical landmarks). A mixture of local anaesthetic (0.375% ropivacaine and 1.0% lidocaine) was injected in each group. Each group was blocked under corresponding diverse ways. The operation time of block, the duration of analgesia and the complications were recorded, the time of pain deprivation of axillary nerve, medial brachial cutaneous nerve, medial antebrachial cutaneous nerve, lateral antebrachial cutaneous nerve, ulnar nerve, median nerve and radial nerve were measured, and the extent of pain sensory block (completeness,part,lack), muscle strength blockade, the effects of anesthesia (excellent,good,failure) during operation were assessed.Results Part one: The ultrasound image of SBP was demonstrated in all patients, the transverse image of SBP was round or oval hypoechoic structures with small internal punctuated echoes. The appearances of whole SBP image were various including the size and number of nerves.⑴the included angle between the skin line and the SBP-to-SA centre line: left: 45.3±17.2 degree, right: 46.3±17.6 degree.⑵The distance of SBP-to-SA: left: 0.53±0.17㎝, right: 0.53±0.18㎝.⑶The skin-to-SA distance: left: 1.51±0.39㎝, right: 1.46±0.39㎝.⑷The skin-to-first rib distance: left: 2.23±0.40㎝, right: 2.23±0.41㎝.⑸The skin-to-SBP distance: left: 0.97±0.29㎝, right: 0.95±0.29㎝. The skin-to-SBP distance had a medial correlation with body weight and body height. Part two:⑴The operation time of block in Group A and Group E were shorter than that in Group B(P<0.05).⑵The time of pain deprivation of medial antebrachial cutaneous nerve and ulnar nerve in Group A and Group E were longer than those in Group B(P<0.05), there was no significant difference among Group B, Group C and Group D(P>0.05).⑶The effects of pain sensory block of medial antebrachial cutaneous nerve, ulnar nerve, medial nerve and medial brachial cutaneous nerve in Group A-to-D were more complete than that in Group E(P<0.05), there was no significant difference in the effects of pain sensory block of axillary nerve, lateral antebrachial cutaneous nerve and radial nerve(P>0.05).⑷There was no significant difference about muscle strength blockade in five groups(P>0.05).⑸The excellent anesthesia rate in Group A and Group B was higher than that in Group E(P<0.05).⑹The duration of analgesia in Group B was longer than that in Group D or Group E(P<0.05).⑺No complication occurred in Group A-to-D. 5 adverse events occurred in Group E (4 cases of vascular puncture, 1 case of mild toxic reaction).Conclusion Part one: The high-resolution sonography can provide good quality ultrasound images in supraclavicular location. The SBP is lateral to SA in the ultrasound images. The advancement of needle and the spread of local anesthetic can be monitored under ultrasound. Part two: Compared with that guided by anatomical landmarks, the effects of pain sensory block and effects of anesthesia during operation were significantly better in group guided by ultrasound (single-injection, three-injection). In addition, the duration of analgesia was longer and fewer complications occurred in groups guided by ultrasound. Compared with single-injection, the operation time of block was longer, but the time of pain deprivation of inferior trunk nerve was shorter and the effect of inferior trunk nerve block was more complete in three-injection groups. Although supraclavicular brachial plexus block was achieved with smaller dose of local anaesthetic when using ultrasound guidance, the duration of analgesia was short. We could not excessively pursuit small dose of local anesthetic leading to reduction of the postoperative analgesia time.