Sonographic assessment of predictors of depth of the corner pocket for ultrasound-guided supraclavicular brachial plexus block

The Lateral Decubitus Body Position Might Improve the Safety of Ultrasound-Guided Supraclavicular Brachial Plexus Nerve Block

Background

To investigate whether body mass index (BMI) and changes in body positioning have any correlation with the distance from the pleura to the inferior trunk of the supraclavicular brachial plexus.

Patients and Methods

Twenty stroke patients with upper limb spasticity and complex regional pain syndrome were recruited for this study. Distance from the pleura to the inferior trunk was measured in the supine position, body turned sideways at 45 °, and in the lateral decubitus position. Correlations between BMI and measured distances in these body positions were evaluated. A linear musculoskeletal ultrasound transducer was used to conduct these distance measurements.

Results

The distance from the pleura to the inferior trunk in the supine position was calculated to have an average of 0.42 ± 0.06 cm (D1), 0.44 ±0.05 (D2) when lying sideways at 45 °, and 0.87 ± 0.08 cm (D3) in the lateral decubitus position. The Kruskal–Wallis test revealed significant differences when comparing D3 with D1, and D3 with D2 (p < 0.001). Positive correlations were observed between BMI and D1 (Spearman’s rho = 0.62, p = 0.004, two-tailed), and between BMI and D2 (Spearman’s rho = 0.61, p = 0.005, two-tailed). The strongest positive correlation was observed between BMI and D3 (Spearman’s rho = 0.78, p < 0.001, two-tailed).

Discussion

In the lateral decubitus body position, the distance from the pleura to the inferior trunk increased significantly by 2-fold and was positively correlated with BMI. The increased distance may improve the safety of the nerve block procedure. As a result, it is recommended that patients be placed in the lateral decubitus body position when performing ultrasound-guided supraclavicular brachial plexus nerve block of the inferior trunk.

A fluoroscopic assessment of brachial plexus block by the supraclavicular approach: Have we been overmedicating?

Background

Ultrasonography-guided supraclavicular brachial plexus block has demonstrated safety as compared with landmark or nerve stimulation techniques. However, the minimum effective analgesic volume (MEAV) necessary for adequate blockade has not been determined. This study was undertaken to assess under fluoroscopy the postinjection spread of different drug volumes with clinical correlation. Secondary outcome measures included correlation of onset of block, block quality, and incidence of side effects.

Methods

This randomized, multiarm, cross-sectional, observational study was conducted at a single tertiary care center. A total of 549 patients were randomly allocated to 3 groups (20 ml, 30 ml, and 40 ml of drug mixture). A local anesthetic drug mixture with a radiopaque dye was administered under ultrasonographic guidance, and postinjection fluoroscopic drug spread was studied.

Results

Surgical anesthesia was achieved in 494 (89.98%) patients with 85.25%, 92.97%, and 91.71% in 20-, 30-, and 40-ml groups, respectively, being significantly low (p = 0.0317) in the 20-mL group. Cephalad and infraclavicular spread was higher in the 40-mL group than in other two groups (p = 0.103). Horner syndrome (HS) was seen in 51.18% of patients. First, ipsilateral superficial cervical plexus block was also observed in 40.22% of patients. Among patients who developed both, ∼60% of patients (99/167) belonged to the 40-mL group.

Conclusions

Optimal MEAV appears between 20 and 30 mL. Higher drug volumes are associated with more cephalad spread and side effects. Drug spread can predict block efficacy as well. It is postulated that loss of sensation in the ipsilateral neck can be used to predict development of hemidiaphragmatic paresis similar to HS.

Inter Scalene Block: Revisiting old technique

Background and Aims:

The technique of percutaneous brachial plexus block has persisted in many variations since first such block given by Hirsheli in 1911.[1] Both supraclavicular and infraclavicular approaches have been described. Consequent to perivascular technique (Winnie and Collins 1964), Winnie described interscalene block (ISB) in 1970.[23] Winnie's was a single deposit block which relied upon volume for its success. It is nearly 50 years that ISB has stood the test of time and has evolved from single to multiple deposits Block. In mid-90s, ultrasound guidance was first explored by anesthetists for regional anesthesia in University of Vienna.[3] As ultrasound guidance is becoming popular and is increasingly available to budding anesthetist, popularity of old technique has started waning. In this study, old technique of ISB was revisited with a view to assess its success rate with established drugs and examine if in light of ultrasound guidance, this technique has become irrelevant for anesthetist today.

Methods:

A retrospective study, a survey with high response rate, was done on success rate of three variations of old technique of ISB in 100 patients. In variation-1, thirty patients received two deposits of local anesthetic in interscalene groove. In variation-2, thirty patients received four deposits of local anesthetic in interscalene groove. In variation-3, forty patients received six deposits of local anesthetic in interscalene groove along with infiltration of both scalene muscles. In none of the variations, paraesthesia was sought or peripheral nerve stimulator (PNS) or imaging gadget was used. Demographic data in three variations were compared statistically using Chi-square and one-way ANOVA test. Success rate among variations was analyzed by Fisher's exact test.

Results:

In variation-1, 17 out of 30, in variation-2, 23 out of 30, and in variation-3, 37 out of 40 blocks were successful.

Conclusion:

Success of ISB given without PNS or ultrasound guidance is directly proportional to the number of deposits of local anesthetic made in interscalene groove.

Assessment of variation in depth of brachial plexus using ultrasound for supraclavicular brachial plexus block in patients undergoing elective upper limb surgery

Background and Aims:

Supraclavicular approach to the brachial plexus may be associated with complications such as pneumothorax, inadvertent vascular puncture, inter-scalene block and neurovascular injuries. The present study was conceived to find out the variation in depth of brachial plexus to suggest the minimum length of needle required to effectively perform the block, thus preventing possible complications.

Methods:

After approval from our Institutional Ethical Committee, informed and written consent was obtained from each of the ninety American Society of Anesthesiologists Physical Status I and II patients recruited, of either sex in the age group of 20–50 years. Supraclavicular fossa was scanned using a high-frequency linear probe, and the distances (shortest distance [SD] from skin to the most superficial neural element and longest distance [LD] from skin to the most deep neural element) were measured using on-screen callipers on optimal frozen image. Pearson correlation was used to find out the relation between these two distances and demographic parameters.

Results:

Mean SD was 0.60 ± 0.262 cm, and mean LD was found to be 1.34 ± 0.385 cm. We observed significant correlation between these two distances with weight and body mass index (BMI).

Conclusion:

Significant correlation was observed between SD and LD with weight and BMI. We suggest that a needle with a shaft length of 3 cm will be sufficient to reach the sheath of the brachial plexus during performance of the block.