Reverse arterial blood flow mediated local anesthetic central nervous system toxicity during axillary brachial plexus block

Clinical presentation of local anesthetic systemic toxicity: a review of published cases, 1979 to 2009

The classic description of local anesthetic systemic toxicity (LAST) generally described in textbooks includes a series of progressively worsening neurologic symptoms and signs occurring shortly after the injection of local anesthetic and paralleling progressive increases in blood local anesthetic concentration, culminating in seizures and coma. In extreme cases, signs of hemodynamic instability follow and can lead to cardiovascular collapse. To characterize the clinical spectrum of LAST and compare it to the classic picture described above, we reviewed published reports of LAST during a 30-year period from 1979 to 2009. Ninety-three cases were identified and analyzed with respect to onset of toxicity and the spectrum of signs and symptoms. Sixty percent of cases followed the classic pattern of presentation. However, in the remainder of cases, symptoms were substantially delayed after the injection of local anesthetic, or involved only signs of cardiovascular compromise, with no evidence of central nervous system toxicity. Although information gained from retrospective case review cannot establish incidence, outcomes, or comparative efficacies of treatment, it can improve awareness of the clinical spectrum of LAST and, theoretically, the diagnosis and treatment of affected patients. The analytic limitations of our method make a strong case for developing a prospective, global registry of LAST as a robust alternative for educating practitioners and optimizing management of LAST.

[Cardiac arrest after axillary plexic anaesthesia with ropivacaine in a chronic kidney failure dialysis patient]

The local anaesthetics are responsible for an important part of morbidity and mortality during conduction anaesthesia. We describe fatal accident plexic anaesthesia with ropivacaine in spite of a classical reanimation measure in a dialysis patient.

Méta-analyse : intérêt du neurostimulateur dans l'amélioration du taux de succès du bloc axillaire

OBJECTIVE

To evaluate the effectiveness of the neurostimulator to improve the success rate of a brachial plexus blockade by the axillary approach.

STUDY DESIGN

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).

CONCLUSION

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.