Question

Is infraclavicular block (ICB) effective and well tolerated compared with other approaches to the brachial plexus in providing regional anaesthesia for surgery on the lower arm?

Relevance to nursing care

The use of regional anaesthesia reduces not only postoperative pain but also the risks of postoperative nausea and vomiting, and postoperative drowsiness, which are commonly associated with general anaesthesia. There are several commonly used techniques of blocking the brachial plexus, but it is not clear which, if any, is the best. This updated systematic review compared the effects of blocking the brachial plexus by injecting local anaesthetic in the area below the collar bone (the ICB) with other techniques.

Study characteristics

The review contained 22 randomized controlled trials (RCTs) that compared ICB with another technique of brachial plexus blockade. Seven new studies were included in this updated version of the review with a total patient enrolment of 1732 participants [1].

The review included all patients, both adults and children, undergoing surgery of the lower arm (hand, forearm or elbow) under regional anaesthesia, including those where a planned combined regional and general anaesthetic was used. The other techniques were axillary block (injection in the armpit area; 14 studies), supraclavicular block (injection in the area just above the collarbone; 6 studies), mid-humeral block (injection in the upper arm; 2 studies) and parascalene block (injection in the lower neck area; 1 study). One study compared an ICB with both an axillary block and a supraclavicular block. Nine studies employed ultrasound-guided ICB. The primary outcome of interest was adequate surgical anaesthesia within 30 min of block completion. Secondary outcomes included need for supplemental local anaesthetic blocks/systemic analgesia, need for general anaesthesia, sensory block of individual nerves, tourniquet pain, onset time of sensory blockade, duration of postoperative analgesia, block performance time, block-associated pain and complications related to the block.

The methodological quality of included trials was sound with an overall low risk of bias. The most common reason for unclear risk of bias was the insufficient detail regarding random sequence generation in 10 studies and allocation concealment in 13 studies. Ten studies lack description in the blinding of the outcome assessor. Performance bias was identified as the most significant methodological limitation. Meta-analysis was undertaken when possible.

Results were as follows:

1. There was no significant difference in the risk of failed surgical anaesthesia 30 min after block completion between ICB and all other brachial plexus blocks (BPBs) [risk ratio 0.88, 95% confidence interval (CI) 0.51-1.52, P = 0.64, 14 studies].

2. Tourniquet pain was significantly less with ICB compared with all other BSBs (risk ratio 0.66, 95% CI 0.47-0.92, P = 0.02, 8 studies).

3. Subgroup analysis by method of nerve localization, and by control group intervention, did not show any statistically significant differences in the risk of failed surgical anaesthesia.

4. ICB was significantly better at providing complete sensory block of the musculocutaneous nerve (risk ratio 0.46, 95% CI 0.27-0.78, P < 0.0040, 3 studies) when compared with a single-injection axillary block.

5. Sensory block onset time was slightly longer for ICB (MD 1.9 min, 95% CI 0.2-3.6 min, P < 0.03, 9 studies).

6. There was no statistically significant difference in the duration of postoperative analgesia between ICB and all other BPBs (MD 4.0 min, 95% CI -6.3 to 14.3 min, P = 0.45, 9 studies).

7. ICB was faster to perform compared with a multiple-injection axillary block (MD -2.7 min, 95% CI -3.4 to -2.0 min, P = 0.04), a multiple-injection mid-humeral block (risk ratio 5.3, 95% CI -6.0 to -3.6 min, P < 0.00001) and a supraclavicular block (MD -0.8 min, 95% CI -1.4 to -0.3 min, P = 0.003). An ultrasound-guided ICB technique showed that this was slightly faster (MD -1.6 min, 95% CI -2.6 to -0.6 min, p = 0.002, 6 studies) than other techniques.

8. There was no significant difference in the proportion of patients requiring general anaesthesia with an ICB compared with other blocks (risk ratio 0.66, 95% CI 0.36-1.21, P = 0.18). When compared with a single-injection axillary block, however, the need for general anaesthesia was significantly less likely with an ICB (risk ratio 0.33, 95% CI 0.13-0.88, P = 0.03, 20 studies).

9. There was no significant difference in block complications such as the risk of Horner's syndrome (risk ratio 2.03, 95% CI 0.50-8.25, P < 0.32, 6 studies) when ICB was compared with blocks below clavicle. When compared with blocks above the clavicle, ICB risk of Horner's syndrome was significantly lower (risk ratio 0.09, 95% CI 0.04-0.21, P < 0.00001, 5 studies).

Implications for nursing care

Infraclavicular block is a valid option for providing surgical anaesthesia of the lower arm. Regardless of whether ultrasound or neurostimulation guidance is used, ICB is as well tolerated and effective as any other technique of brachial plexus block. It is also more effective at preventing tourniquet pain. When compared with more complex multiple-injection techniques of axillary block and mid-humeral block, ICB also has the advantage of being faster to perform.

Implications for research

Neurostimulation in modern brachial plexus blockade has largely been replaced by ultrasound guidance making all commonly used techniques more effective. It is unlikely that additional comparative trials will lead to a demonstration of a difference in efficacy between the various techniques, given the high success rates reported in recent studies. The key factors that will determine an individual practitioner's choice of which brachial plexus block to perform will be based upon the learning curves, ease of block performance, and adverse effects. These areas should be the focus of research in the future.

Reference