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Three Part Question

In [patients with a distal radial fracture requiring manipulation under Bier's block] does [injection in proximal to the fracture site (i.e. the hand) as compared to proximal injection (i.e. the antecubital fossa) during Biers' block anaesthesia] produce [a less satisfactory block in terms of pain for the patient]?

Clinical Scenario

A 65 year old lady presents to the emergency department having fallen onto the outstretched hand. She sustains a distal radial fracture with dorsal angulation and displacement. You consider that it would benefit from manipulation and arrange for her to have a Bier's block for anaesthesia.
You are about to place the venflon on the affected arm in the ante-cubital fossa when you stop and wonder if it would be better placed in the hand, closer to the fracture site.

Search Strategy

OVID Medline via ATHENS. 1966 - May 2006
EMBASE via ATHENS. 1980 - May 2006
COCHRANE database. Edition 2. 2006.
OVID and EMBASE
[bier's block.af OR regional anaesthesia.mp] AND [(injection adj5 site).mp]
Cochrane
radius and anaesthesia

Search Outcome

OVID. 8 citations. One relevant
EMBASE. 13 citations. no new papers found
COCHRANE. 2 citations. no new papers found

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Blyth MJG. 1995 Scotland	100 patients undergoing manipulation of a distal radial fracture. Allocation was by randomisation. Collected over a 3 month period. 40ml of 0.5% Prilocaine was used at either the ACF or dorsum of the hand.	PRCT	Mean pain at fracture site on 10 point scale	2.66 in dorsum group vs 3.46 in ACF group. p>0.05	Method of randomisation not given. No power study. Not blinded. Analysis using t tests, when should have used non-parameteric analysis.
			Pain at cuff site	3.16 in dorsum group vs 3.30 in ACF group. p>0.05
			Complications (failed cannulation, haematoma formation, bleeding)	19 in hand group. 3 in ACF group. Stated as significant by authors, but no value given.

Comment(s)

This question arises for two reasons. Firstly one technique may be better than the other in terms of pain. Secondly, it is technically more difficult to perform the manipulation and place the POP if the cannulla is in the hand. This study described above sheds some light on the problem but contains significant methodological and analytical flaws that make it's interpretation difficult. In particular the analysis may hide some patients with severe pain (as only mean scores are compared). Whilst the evidence is not compelling there will be those who will interpret this evidence as no difference equates to "use the ACF" as it is easier and has apparently fewer complications. This may be true from a pragmatic perspective, but the published evidence is insufficient to support it. From my own perspective I will probably carry on using the ACF.

Clinical Bottom Line

The evidence is insufficiently sound to decide whether the dorsum of the hand or the antecubital fossa is the best place to site a cannulla when performing a Bier's block. However, there is a pragmatic argument for using the ACF.

References

1. Blyth MJ, Kinninmonth AW, Asante DK. Bier's block: a change of injection site Journal of Trauma-Injury Infection and critical care 1995;39(4):726-728