[Brachial plexus block with levobupivacaine at the humeral canal: comparison of a small volume at high concentration with a large volume at low concentration]. / Bloqueo del plexo braquial a nivel humeral con levobupivacaína: estudio comparativo alta concentración/pequeiio volumen frente a baja concentraci6n/alto volumen.

OBJECTIVE: To assess differences in the brachial plexus block in 2 groups who received the same dose of levobupivacaine: 1 group received a small volume of solution at high concentration and the other group received a large volume in solution at low concentration. MATERIAL AND METHODS: A prospective, randomized clinical trial enrolling 69 patients scheduled for wrist and/or hand surgery with a brachial plexus block with levobupivacaine in the humeral canal. Nerve stimulation was used to locate a response from the 4 terminal nerves in the brachial plexus. In the group receiving a larger volume, 10 mL of a solution of levobupivacaine at a concentration of 0.375% was used for each nerve. In the high concentration group receiving a smaller volume, levobupivacaine was used at a concentration of 0.75% in 5 mL for each nerve. Sensory latency was assessed by the pin prick technique. Motor block, the success rate (percentage), and duration of sensory and motor blockades were also evaluated. RESULTS: The full sensory block was significantly more efficacious in the large volume group than in the high concentration group (85.3% vs 51.6%, P = 0.003). A full motor block was reached in a small percentage of patients in both groups. There were no significant differences in latency or duration of block. CONCLUSIONS: The success rate was lower in the group receiving the smaller volume at a higher concentration. It is advisable to administer local anesthetics in larger volumes at lower concentrations to improve block quality. Latency and duration were similar in both groups.

Bloqueo del plexo braquial a nivel humeral con levobupivacaína: estudio comparativo alta concentración/pequeño volumen frente a baja concentración/alto volumen / Brachial plexus block with levobupivacaine at the humeral canal: comparison of a small volume at high concentration with a large volume at low concentration

OBJETIVO: Valorar las diferencias en el bloqueo del plexo braquial entre dos grupos en los que se emplea la misma dosis de levobupivacaína: un grupo con bajo volumen/alta concentración y el otro con alto volumen/ baja concentración. MATERIAL Y MÉTODOS: Estudio prospectivo randomizado de 69 pacientes programados para cirugía de muñeca y/o mano, a los que se realizó un bloqueo del plexo braquial en el canal humeral con levobupivacaína. Se buscó la respuesta de los cuatro nervios terminales del plexo braquial mediante neuroestimulación. En el grupo volumen se utilizó levobupivacaína al 0,375%, 10 mL en cada nervio y en el grupo concentración se utilizó levobupivacaína al 0,75%, 5 mL en cada nervio. Se valoró la latencia sensitiva del bloqueo mediante la técnica del pinchazo, el bloqueo motor y el porcentaje de éxito de la técnica. También se recogió la duración del bloqueo sensitivo y motor. RESULTADOS: En el grupo volumen, el bloqueo sensitivo completo fue significativamente más efectivo que en el grupo concentración (85,3% vs 51,6%; p=0,003). El bloqueo motor completo se alcanzó en un porcentaje bajo de pacientes en ambos grupos. No hubo diferencias significativas en cuanto a la latencia y a la duración del bloqueo. CONCLUSIONES: Se obtuvo un bajo porcentaje de éxitos en el grupo bajo volumen/alta concentración. Es aconsejable utilizar volúmenes más elevados de anestésico local para mejorar la calidad del bloqueo. La latencia y la duración en ambos grupos fueron similares (AU)

OBJECTIVE: To assess differences in the brachial plexus block in 2 groups who received the same dose of levobupivacaine: 1 group received a small volume of solution at high concentration and the other group received a large volume in solution at low concentration. MATERIAL AND METHODS: A prospective, randomized clinical trial enrolling 69 patients scheduled for wrist and/or hand surgery with a brachial plexus block with levobupivacaine in the humeral canal. Nerve stimulation was used to locate a response from the 4 terminal nerves in the brachial plexus. In the group receiving a larger volume, 10 mL of a solution of levobupivacaine at a concentration of 0.375% was used for each nerve. In the high concentration group receiving a smaller volume, levobupivacaine was used at a concentration of 0.75% in 5 mL for each nerve. Sensory latency was assessed by the pin prick technique. Motor block, the success rate (percentage), and duration of sensory and motor blockades were also evaluated. RESULTS: The full sensory block was significantly more efficacious in the large volume group than in the high concentration group (85.3% vs 51.6%, P=0.003). A full motor block was reached in a small percentage of patients in both groups. There were no significant differences in latency or duration of block. CONCLUSIONS: The success rate was lower in the group receiving the smaller volume at a higher concentration. It is advisable to administer local anesthetics in larger volumes at lower concentrations to improve block quality. Latency and duration were similar in both groups (AU)