[The neurostimulator for brachial plexus blockade by the axillary approach: a metaanalysis on its efficacy to increase the success rate].
OBJECTIVE
To evaluate the effectiveness of the neurostimulator to improve the success rate of a brachial plexus blockade by the axillary approach.


METHODS
Metaanalysis.


METHODS
Ten prospective randomized studies comparing a neurostimulating technique (NST) of brachial plexus blockade performed by the axillary approach to another technique were kept for analysis. A successful block was defined as blockade of the four following nerves: radial, median, ulnar and musculocutaneous. Data were entered on an intention to treat basis and were analyzed with a random model. A p<0.05 was considered significant.


RESULTS
Data were heterogenous (p < 0.001) and the Cochran-Mantel-Haenzel test showed that the neurostimulator does not improve the success rate of brachial plexus blocks performed by the axillary approach when all available studies are considered as a whole (p = 1). For the subgroup of studies where four nerves were stimulated however, the NST decreases the incidence of failed block by 25% (95% CI = 7-42%) (p < 0.0001). There were 12 patients with systemic signs of local anesthetics toxicity when a NST was used compared to 28 when it was not (p = 0.04), relative risk of 0.7 (95% CI= 0.6-0.8).


CONCLUSIONS
This study shows that the neurostimulator improves the success rate of brachial plexus blocks performed by the axillary approach only when three nerves or more are stimulated and its use decreases the incidence of systemic local anaesthetics toxicity.
Guay
J
J
Département d'anesthésie-réanimation, hôpital Maisonneuve-Rosemont, université de Montréal, 5415, boulevard l'Assomption, Montréal, Québec, Canada H1T 2M4. joanne.guay@umontreal.ca
D000779:Anesthetics, Local / Q000009:adverse effects; D001917:Brachial Plexus / Q000502:physiology*; D004558:Electric Stimulation; D006801:Humans; D008475:Median Nerve / Q000502:physiology; D009138:Musculocutaneous Nerve / Q000502:physiology; D009407:Nerve Block / Q000379:methods*; D011826:Radial Nerve / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D014459:Ulnar Nerve / Q000502:physiology
D000779:Anesthetics, Local