Comparison of transarterial and multiple nerve stimulation techniques for axillary block using lidocaine with epinephrine

Imbelloni, Luiz Eduardo; Beato, Lúcia; Cordeiro, José Antônio

doi:10.1590/S0034-70942005000100005

Abstracts

BACKGROUND AND OBJECTIVES: High-dose transarterial technique results in highly effective axillary block. The multiple nerve stimulation technique (MNS) requires more time and experience. This prospective study aimed at comparing onset and success rate of multiple-injection axillary brachial plexus block using two methods of nerve location: transarterial or multiple nerve stimulation technique. METHODS: Axillary block was initially induced with 800 mg lidocaine with epinephrine. The transarterial group received deeply injected 30 mL of 1.6% lidocaine with epinephrine, and 20 mL superficially to the axillary artery. For the multiple nerve stimulation group, three terminal motor nerves were electrolocated and blocked with 20 mL, 20 mL and 10 mL. Blockade was considered effective when analgesia was present in all sensory nerves distal to the elbow. RESULTS: Onset (8.8 ± 2.3 min versus 10.2 ± 2.4 min; p-value = 0.010) was significantly shorter in the transarterial group. Complete sensory block of all four nerves (median, ulnar, radial and musculocutaneus) was achieved in 92.5% versus 83.3% for multiple nerve stimulation group and transarterial group, respectively, without significant difference (p = 0.68). Musculocutaneous nerve was significantly easier to be blocked with the aid of peripheral nerve stimulator (p = 0.034). CONCLUSIONS: Both MNS technique for axillary block with nerve stimulator (3 injections) and transarterial technique (2 injections) promote similar results. Musculocutaneous nerve is more easily blocked with the aid of peripheral nerve stimulator. MNS technique has required less supplementary blocks and has delayed beginning of surgery.

ANESTHETIC, Local; ANESTHETIC, Local; ANESTHETIC TECHNIQUES, Regional; ANESTHETIC TECHNIQUES, Regional

JUSTIFICATIVA E OBJETIVOS: A técnica transarterial com grandes doses de anestésico local resulta em alta efetividade para o bloqueio axilar do plexo braquial. A técnica utilizando múltiplos estímulos exige mais tempo e maior experiência. Este estudo prospectivo compara a latência e o índice de sucesso do bloqueio do plexo braquial usando duas técnicas de localização: transarterial ou múltipla estimulação dos nervos. MÉTODO: A lidocaína com epinefrina, 800 mg, foi usada inicialmente para o bloqueio axilar. No grupo transarterial, 30 mL de lidocaína a 1,6% com epinefrina foram injetados profundamente e 20 mL superficialmente à artéria axilar. No grupo de múltipla estimulação, três nervos foram localizados eletricamente e bloqueados com volumes 20 mL, 20 mL e 10 mL da solução. O bloqueio foi considerado efetivo quando a analgesia estava presente em todos os nervos na área distal ao cotovelo. RESULTADOS: O tempo de latência (8,8 ± 2,3 min versus 10,2 ± 2,4 min; p-valor = 0,010) foi significativamente menor no grupo transarterial. Bloqueios sensitivos completos nos quatro nervos (mediano, ulnar, radial e musculocutâneo) foram obtidos em 92,5% versus 83,3% no grupo de múltipla estimulação e acesso transarterial, respectivamente sem diferença significativa (p-valor = 0,68). O nervo musculocutâneo foi significativamente mais fácil de bloquear com o estimulador de nervo periférico (p = 0,034). CONCLUSÕES: A técnica de múltipla estimulação para o bloqueio axilar usando estimulador de nervos (3 injeções) e a técnica transarterial (2 injeções) produzem resultados semelhantes na qualidade do bloqueio. O nervo musculocutâneo é mais facilmente bloqueado com o uso do estimulador de nervo periférico. A técnica de múltipla estimulação necessitou menor suplementação do bloqueio e aumentou o tempo para o início da cirurgia.

ANESTÉSICOS, Local; ANESTÉSICOS, Local; TÉCNICAS ANESTÉSICAS, Regional; TÉCNICAS ANESTÉSICAS, Regional

JUSTIFICATIVA Y OBJETIVOS: La técnica transarterial con grandes dosis de anestésico local resulta en alta efectividad para el bloqueo axilar del plexo braquial. La técnica de utilizar múltiples estímulos exige más tiempo y mayor experiencia. Este estudio prospectivo compara la latencia y el índice de éxito del bloqueo del plexo braquial usando dos técnicas de localización: transarterial o múltipla estimulación de los nervios. MÉTODO: La lidocaína con epinefrina, 800 mg, fue usada inicialmente para el bloqueo axilar. En el grupo transarterial, 30 mL de lidocaína a 1,6% con epinefrina fueron inyectados profundamente y 20 mL superficialmente a la arteria axilar. En el grupo de múltipla estimulación, tres nervios fueron localizados eléctricamente y bloqueados con volúmenes 20 mL, 20 mL y 10 mL de la solución. El bloqueo fue considerado efectivo cuando la analgesia estaba presente en todos los nervios en la área distal al codo. RESULTADOS: El tiempo de latencia (8,8 ± 2,3 min versus 10,2 ± 2,4 min; p-valor = 0,010) fue significativamente menor en el grupo transarterial. Bloqueos sensitivos completos en los cuatro nervios (mediano, ulnar, radial y musculocutáneo) fueron logrados en un 92,5% versus 83,3% en el grupo de múltipla estimulación y acceso transarterial, respectivamente sin diferencia significativa (p-valor = 0,68). El nervio musculocutáneo fue significativamente más fácil de bloquear con el estimulador de nervio periférico (p = 0,034). CONCLUSIONES: La técnica de múltipla estimulación para el bloqueo axilar usando estimulador de nervios (3 inyecciones) y la técnica transarterial (2 inyecciones) producen resultados semejantes en la calidad del bloqueo. El nervio musculocutáneo es más facilmente bloqueado con el uso del estimulador del nervio periférico. La técnica de múltipla estimulación necesitó menor suplementación del bloqueo y aumentó el tiempo para el inicio de la cirugía.

SCIENTIFIC ARTICLE

Comparison of transarterial and multiple nerve stimulation techniques for axillary block using lidocaine with epinephrine^* * Received from Instituto de Anestesia Regional, São José do Rio Preto, SP

Comparación de las técnicas transarterial y de estimulación de múltiples nervios para bloqueo del plexo braquial por vía axilar usando lidocaína con epinefrina

Luiz Eduardo Imbelloni, TSA, M.D.^I; Lúcia Beato, TSA, M.D.^II; José Antônio Cordeiro, M.D.^III

^IDiretor do Instituto de Anestesia Regional do Hospital de Base de São José do Rio Preto, SP; Anestesiologista da Clínica São Bernardo e Casa de Saúde Santa Maria. Rio de Janeiro, RJ

^IIAnestesiologista da Clínica São Bernardo e Casa de Saúde Santa Maria. Rio de Janeiro

^IIIProfessor na Faculdade de Medicina de São José do Rio Preto, FAMERP, São José do Rio Preto, SP

^{Correspondence} Correspondence to Dr. Luiz Eduardo Imbelloni Address: Av. Epitácio Pessoa, 2356/203 Lagoa ZIP: 22471-000 City: Rio de Janeiro, Brazil E-mail: dr.imbelloni@terra.com.br

SUMMARY

BACKGROUND AND OBJECTIVES: High-dose transarterial technique results in highly effective axillary block. The multiple nerve stimulation technique (MNS) requires more time and experience. This prospective study aimed at comparing onset and success rate of multiple-injection axillary brachial plexus block using two methods of nerve location: transarterial or multiple nerve stimulation technique.

METHODS: Axillary block was initially induced with 800 mg lidocaine with epinephrine. The transarterial group received deeply injected 30 mL of 1.6% lidocaine with epinephrine, and 20 mL superficially to the axillary artery. For the multiple nerve stimulation group, three terminal motor nerves were electrolocated and blocked with 20 mL, 20 mL and 10 mL. Blockade was considered effective when analgesia was present in all sensory nerves distal to the elbow.

RESULTS: Onset (8.8 ± 2.3 min versus 10.2 ± 2.4 min; p-value = 0.010) was significantly shorter in the transarterial group. Complete sensory block of all four nerves (median, ulnar, radial and musculocutaneus) was achieved in 92.5% versus 83.3% for multiple nerve stimulation group and transarterial group, respectively, without significant difference (p = 0.68). Musculocutaneous nerve was significantly easier to be blocked with the aid of peripheral nerve stimulator (p = 0.034).

CONCLUSIONS: Both MNS technique for axillary block with nerve stimulator (3 injections) and transarterial technique (2 injections) promote similar results. Musculocutaneous nerve is more easily blocked with the aid of peripheral nerve stimulator. MNS technique has required less supplementary blocks and has delayed beginning of surgery.

Key words: ANESTHETIC, Local: epinephrine, lidocaine; ANESTHETIC TECHNIQUES, Regional: axillary block, brachial plexus

RESUMEN

JUSTIFICATIVA Y OBJETIVOS: La técnica transarterial con grandes dosis de anestésico local resulta en alta efectividad para el bloqueo axilar del plexo braquial. La técnica de utilizar múltiples estímulos exige más tiempo y mayor experiencia. Este estudio prospectivo compara la latencia y el índice de éxito del bloqueo del plexo braquial usando dos técnicas de localización: transarterial o múltipla estimulación de los nervios.

MÉTODO: La lidocaína con epinefrina, 800 mg, fue usada inicialmente para el bloqueo axilar. En el grupo transarterial, 30 mL de lidocaína a 1,6% con epinefrina fueron inyectados profundamente y 20 mL superficialmente a la arteria axilar. En el grupo de múltipla estimulación, tres nervios fueron localizados eléctricamente y bloqueados con volúmenes 20 mL, 20 mL y 10 mL de la solución. El bloqueo fue considerado efectivo cuando la analgesia estaba presente en todos los nervios en la área distal al codo.

RESULTADOS: El tiempo de latencia (8,8 ± 2,3 min versus 10,2 ± 2,4 min; p-valor = 0,010) fue significativamente menor en el grupo transarterial. Bloqueos sensitivos completos en los cuatro nervios (mediano, ulnar, radial y musculocutáneo) fueron logrados en un 92,5% versus 83,3% en el grupo de múltipla estimulación y acceso transarterial, respectivamente sin diferencia significativa (p-valor = 0,68). El nervio musculocutáneo fue significativamente más fácil de bloquear con el estimulador de nervio periférico (p = 0,034).

CONCLUSIONES: La técnica de múltipla estimulación para el bloqueo axilar usando estimulador de nervios (3 inyecciones) y la técnica transarterial (2 inyecciones) producen resultados semejantes en la calidad del bloqueo. El nervio musculocutáneo es más facilmente bloqueado con el uso del estimulador del nervio periférico. La técnica de múltipla estimulación necesitó menor suplementación del bloqueo y aumentó el tiempo para el inicio de la cirugía.

INTRODUCTION

Brachial plexus may be located in different ways, including paresthesia, transarterial puncture, loss of nervous sheath resistance and neurostimulation. Axillary route has been indicated for forearm, arm and hand procedures ^1-3. The multiple stimulation technique during axillary block, in which each nerve is located with stimulator and injections are performed separately, provides high success rates and decreases installation time ^4-7.

The axilla is a region at low risk of vital structures damage, being the axillary artery an excellent guide for axillary block. The transarterial technique is performed by injecting local anesthetics in two different areas separated by the axillary artery and has low incidence of failures^1,5. Neurostimulation allows the easy identification of each of the four possible motor responses: median, ulnar and radial nerves stimulated within the nervous sheath, and musculocutaneous nerve in the upper axilla or close to coracobrachial muscle. This way, neurostimulation allows for fractional and directed local anesthetic injection and, differently from paresthesia search with a needle, has a low probability of direct nervous trauma.

Several studies on individualized brachial plexus block have shown that upper limb anesthetic extension and depth were better with location and blockade of the 4 terminal branches, notwithstanding the longer time for the procedure, which would be balanced by faster onset ^4-8.

This prospective study aimed at comparing onset, duration, effectiveness and failures of brachial plexus block induced with two techniques to identify the presence of the needle in the axillary perivascular compartment: multiple stimulation and transarterial perivascular injection.

METHODS

After the Publication and Disclosure Board of Directors approval, participated in this prospective study 70 patients aged 20 to 60 years, physical status ASA I and II, submitted to orthopedic forearm and hand surgeries who were randomly distributed in two groups (group MNS = 40 patients and group TA = 30 patients) according to the technique. All patients gave their informed consent after being informed in detail about the technique.

Patients were not premedicated. After venoclysis with 18G or 20G catheter, lactated Ringer's solution was slowly injected. Monitoring in the operating room consisted of continuous ECG at CM5, noninvasive blood pressure and pulse oximetry. The patients received 50 to 100 µg intravenous fentanyl associated to 10 mg metochlopramide and were only sedated with midazolam after blockade installation and beginning of surgery.

Multiple Stimulation Technique (MNS)

Patients were placed in the supine position with 90º arm abduction and forearm extended or flexed. Axillary artery was drawn in the biceps muscle sulcus, on the line connecting the umeral insertion of pectoral and greater dorsal muscles. A point was marked 3 cm below this, were infiltration was performed anterior and posterior to the artery for the entry of the needle connected to the stimulator.

After a skin wheal raised on the marked point, a B. Braun 22G 0.70 x 50 mm electrically isolated needle was connected to a peripheral nerve stimulator (Stimuplex^®R, B. Braun Melsungen AG) adjusted to release a pulsatile square 1 mA current with intensity decreased to 0.5 mA and inserted in 30º angle with the skin posterior to the axillary artery. We tried to stimulate the ulnar nerve with responses of thenar and hypothenar eminence muscles and clamping of fifth finger and thumb, or the radial nerve with hand extension.

Recently prepared 20 mL of 1.6% lidocaine with 1:200,000 epinephrine were injected. Needle was then removed and reinserted anterior to the axillary artery, in an attempt to stimulate the median nerve and obtain muscle contractions of anterior forearm and hand flexion. At this point, additional 20 mL of the prepared solution were injected. After, needle was removed from the axillary bundle and musculocutaneous nerve was looked for by orienting the needle toward the coracoid apophysis at the insertion of the coracobrachial muscle. When biceps contraction and flexion of the forearm over the arm were reached, 10 mL of the prepared solution were injected.

Five randomly selected patients received 1 mL iohexol contrast (300 mg.mL^-1) in each nerve before anesthetic injection for radiological evaluation.

Transarterial Technique (TA)

Patients were placed in the supine position with 90º arm abduction, flexed elbow and hand under the head. Axillary artery was palpated and marked. A 30 x 8 needle perpendicular to the artery was slowly introduced until blood reflux was obtained, when it was introduced slightly beyond until artery transfixation, confirmed by the lack of reflux. At this moment, recently prepared 30 mL of 1.6% lidocaine with 1:200000 epinephrine were slowly injected observing possible signs of vascular injection. Needle was then slowly backed, going once more through the artery lumen and being positioned anterior to it, when remaining 20 mL of the solution were injected. Needle was then removed and arm was positioned along the body with axillary compression. Five randomly selected patients received 1 mL iohexol contrast (300 mg.mL^-1) in each side of the artery before anesthetic injection for radiological evaluation.

Analgesia was evaluated in both groups by skin clamping and observing patients' pain manifestations, aiming at determining the extension of sensory block of musculocutaneous nerve in forearm radial border, radial nerve in dorsal face of hand, ulnar nerve in medial hand and fifth finger, and median nerve in the palm. The following parameters were evaluated: 1) anesthetic onset: time elapsed from beginning of puncture to loss of sensitivity in the four nerves; 2) sensory block duration: time elapsed between beginning of puncture and total sensory recovery; 3) motor block duration: time elapsed between beginning of puncture and total recovery of blocked limb; 4) tourniquet perception; and 5) complications and side effects.

Blockade was considered complete if all nerves were blocked with the preconized volume. If there was need for additional injection or anesthetic complementation, blockade was considered incomplete. In this case, additional anesthetic dose would only involve the nerve of the unblocked area. Blockade failure was defined as the need for general anesthesia.

Lidocaine toxicity signs were investigated during anesthetic injection, such as hum, metal taste, heat sensation, visual disorders, dizziness or muscle contractions.

Tenoxicam (40 mg) and dipirone (30 mg.kg^-1) in 100 mL lactated Ringer's were administered at surgery completion and patients were transferred to the ward. All patients were followed up for 48 hours via telephone to check for complications on blockade site. If there were any signs, patient should return to the hospital to be evaluated by the authors. All patients were asked about their satisfaction with the technique.

Results were evaluated by t test with Welch correction for levels of freedom and by Fisher's exact test to compare two percentages, considering significant p < 0.05.

RESULTS

Continuous variables results are shown as mean ± standard deviation. Distribution by age, weight, height and gender is shown in table I; sensory and motor block onset and duration are shown in table II. Contrasted study of each nerve with the multiple stimulation technique is shown in figure 1, figure 2 and figure 3, and with the transarterial technique in figure 4 and figure 5.

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Brazilian Journal of Anesthesiology, 2005; 55: 1: 40 -49

Comparison of transarterial and multiple nerve stimulation techniques for axillary block using lidocaine with epinephrine