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Rev. Bras. Anestesiol. vol.55 no.4 Campinas July/Aug. 2005
LETTER TO THE EDITOR
Comparison of transarterial and multiple nerve stimulation techniques for axillary block using lidocaine with epinephrine
I thank Mrs. Editor for the opportunity of adding some comments to the above-mentioned study 1.
1. The discussion 1 mentions successful evaluation of all forearm nerves after the first anesthetic injection. However, the study describes multiple nerve stimulation (MNS) with four injections (radial, ulnar, median and musculocutaneous of forearm) and the transarterial technique (TAT) with two injections (posterior and anterior to axillary artery).
2. Considering that TAT is the most, or one of the most effective techniques 2,3, the study 1 has been more successful with the NMS technique, probably due to the following events: TAT characteristics 1 were puncture perpendicular to skin, not in the axillary hollow (made unfeasible by anatomy), just arterial transfixation and two injections, 83.3% success rate; while MNS characteristics were puncture oblique to skin (30º), needle tip more proximal to axillary hollow, 92.5% success rate. It has been observed that TAT with two posterior arterial transfixations and three axillary hollow injections, as performed by Cockings et al. 3, had 99% success rate, similar to the first study by Imbelloni et al. 4. Axillary arterial transfixation allows for the intercommunication of sub-compartments housing isolated nerves within brachial plexus neurovascular sheath (NVS) during puncture pathway. So, it is supposed that with two posterior arterial transfixations and three injections outcome would be more effective. And more; oblique puncture in the axillary hollow results in more proximal anesthetic solution spread 2, similar to short catheter positioning, and may distally reach plexus cords and, easily, axillary terminal nerves and musculocutaneous nerve of forearm early emerging from NVS. Conversely, with perpendicular puncture distant from the axillary hollow, this pharmacokinetics is made difficult, very often sparing both mentioned nerves. It has been observed that with the classic abducted arm position 5,6, humeral head is not an obstacle for anesthetic solution spread. However, we cannot forget anatomic aberrations of plexus components which are, undoubtedly, the major responsible (villains) for anesthetic block failures even during impeccable techniques.
3. Local anesthetics (LA) toxicity depends on vascular absorption speed in loco. As opposed to intercostal space, in sites with high amounts of fatty tissue such as inside NVS 7, large LA volumes (lipophylic in nature) with epinephrine 8 may go beyond maximum recommended doses 9 without toxic effects 8. LA toxicity should be correlated to two variables: plasma concentration and toxicology syndrome (clinical signs and symptoms). In some cases, there is no parallel among them, as it has been shown 1,8,10. It is worth reminding that excessive infiltrative doses of LA with epinephrine are used in cosmetic plastic surgeries without toxic manifestations. Epinephrine-induced vasoconstriction, anesthetic solution removal by immediate liposuction or even its loss through surgical incisions and broad removal of tissue containing high injected solution volumes, do not easily promote toxic plasma concentrations. Conversely, anesthetic solution absorption may by more intensive close to the 40th minute reaching the highest rate in approximately 60minutes after injection 8,10.
Karl Otto Geier, M.D.
01. Imbelloni LE, Beato L, Cordeiro JA - Comparação das técnicas transarterial e de estimulação de múltiplos nervos para bloqueio do plexo braquial por via axilar usando lidocaína com epinefrina. Rev Bras Anestesiol, 2005;55:40-49.
02. Cockings E, Moore PL, Lewis RC - Transarterial brachial plexus blockade using high doses of 1.5% mepivacaine. Reg Anesth, 1987;12:159-164.
03. King RS, Urquhart B, Urquart B et al - Factors influencing the success of brachial plexus block. Reg Anesth, 1990;15: (Suppl):63.
04. Imbelloni LE, Pinto AL, Neumann CR - Bloqueio do plexo braquial pela via transarterial com altas doses de lidocaína a 1,6%. Rev Bras Anestesiol, 1989;39:273-276.
05. Winnie AP, Tay CH, Patel KP et al - Pharmacokinetics of local anesthetics during plexus blocks. Anesth Analg, 1977:56: 852-861.
06. Thompson GE, Rorie DK - Functional anatomy of the brachial plexus sheaths. Anesthesiology, 1983;59:117-122.
07. Beck H, Lierse W, Dziadzka A et al - Axillary block of the brachial plexus: a new anatomical view of fat and septa distribution and the clinical relevancy. Reg Anesth, 1990;15:(Suppl):51.
08. Palve H, Kirvela O, Olin H et al - Maximum recommended doses of lignocaine are not toxic. Br J Anaesth, 1995;74:704-705.
09. Scott DB - "Maximum recommended doses" of local anaesthetic drugs. Br J Anaesth, 1989;63:373-374.
10. Geier KO - Analgesia regional periférica com lidocaína em paciente queimado. Relato de caso. Rev Bras Anestesiol, 2004;54:247-251.
We thank the comments of Otto Geier, one of the most important Brazilian regional anesthesia investigator, about our study 1. Originally, peripheral blocks were performed with paresthesia or with "blind" access (loss of resistance). Blockade needle has to be in direct contact with the nerve to produce paresthesia. Transarterial access is identified when the needle enters the artery. This technique has been described in different ways, as Geier has well shown in his letter: puncture perpendicular to skin, oblique to skin, more proximal to axillary hollow, one or more artery transfixations, anterior or posterior deposit of high local anesthetic volumes, anterior and posterior deposit of equal volume with different success rates.
At a time when there was no axillary neurovascular space concept 2, Accardo and Adriani 3, in 1949, have used multiple injections to assure homogeneous blockade extension, in a way to individually block the four terminal brachial plexus branches (musculocutaneous, radial, median and ulnar). Then, after studying frozen cadavers, the concept of perivascular local anesthetic spread was developed to explain incomplete block 4. Thompson and Rorie 5 have described conjunctive septa in the axillary space leading to incomplete anesthesia, and Partridge et al. 6 have observed that these were incomplete septa. By that time, both single and multiple injection techniques have coexisted without one being proven better than the other.
Electric neurostimulation was introduced in the 1980s 7. With the aid of peripheral nerve stimulator, the needle no longer has to be in direct contact with the nerve and there is no need for arterial transfixation. In theory, nerve stimulator decreases the potential of nervous post-trauma complications or even of local anesthetic toxicity. Stimulation by the stimulator results in specific motor response. So, each nerve may be individually stimulated, located and blocked with increased blockade success rate, fact which has been observed in our study 1.
The neurostimulator allows for directed fractional local anesthetic injection and is different from the needle paresthesia technique for the low probability of direct nervous trauma. Several studies were carried out with this technique and have shown, as in our study, that extension and quality of upper limb anesthesia with axillary block were better with location of the four terminal branches, notwithstanding the longer time to perform the technique, however with shorter onset 8,9.
Similarly, results were better with the stimulation of two nerves as compared to neurostimulation and single injection 10. Trying to answer how many stimulations were needed for better results, it has been shown that with four stimulations success rate was 100%, with three 90%, with two 60% and with one stimulation 40% 11. In addition, authors have not found poorer acceptance of the multiple stimulations procedure as compared to single stimulation.
We would like to stress the importance of Geier's comments, not only about brachial plexus axillary approach, but also about local anesthetics toxicity in these compartments, showing that large local anesthetic volumes associated or not to epinephrine 12, may go beyond maximum recommended doses 13 without toxic effects 1,12,14.
Anyway, it is important to highlight that excessive insistence in locating the four terminal brachial plexus branches should be avoided, since this may result in patients' dissatisfaction. However, based on current literature, it should be reminded that four locations are better than three, three are better than two and two are better than one. So, peripheral nerve stimulator utilization should be encouraged.
Luiz Eduardo Imbelloni, TSA, M.D.
Lúcia Beato, TSA, M.D.
José Antonio Cordeiro, M.D.
01. Imbelloni LE, Beato L, Cordeiro JA - Comparação das técnicas transarterial e de estimulação de múltiplos nervos para bloqueio do plexo braquial por via axilar usando lidocaína com epinefrina. Rev Bras Anestesiol, 2005;55:1:40-49.
02. Winnie AP, Collins VJ - The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology, 1964;25:353-363.
03. Accardo NJ, Adriani J - Brachial plexus block: a simplified technique using the axillary route. South Med J, 1949;42:920-923.
04. Vester-Andersen T, Broby-Johansen U, Bro-Rasmussen F - Perivascular axillary block. VI: the distribution of gelatine solution injected into the axillary neurovascular sheath of cadavers. Acta Anaesthesiol Scand, 1986;30:18-22.
05. Thompson GE, Rorie DK - Functional anatomy of the brachial plexus sheaths. Anesthesiology, 1983;59:117-122.
06. Partridge BL, Katz J, Benirschke K - Functional anatomy of the brachial plexus sheath: implications for anesthesia. Anesthesiology, 1987;66:743-747.
07. Pither CE, Raj P, Ford DJ - The use of peripheral nerve stimulator for regional anesthesia. Reg Anesth, 1985;10:49-58.
08. Koscielniak-Nielsen ZJ, Stens-Pedersen HL, Knudesen Lippert F - Readiness for surgery after axillary block: single or multiple injection techniques. Eur J Anaesthesiol, 1997;14:164-171.
09. Koscielniak-Nielsen ZJ, Nielsen PR, Nielsen SL et al - Comparison of transarterial and multiple nerve stimulation techniques for axillary block using a high dose of mepivacaine with adrenaline. Acta Anaesthesiol Scand, 1999;43:398-404.
10. Inberg P, Annila I, Annila P - Double-injection method using peripheral nerve stimulator is superior to single injection in axillary plexus block. Reg Anesth Pain Med, 1999;24:509-513.
11. Serradell Catalan A, Moncho Rodrigues JM, Santos Carnes JA et al - Anestesia de plexo braquial por via axilar. Cuántas respuestas buscamos com neuroestimulación? Rev Esp Anestesiol Reanim, 2001;48:356-363.
12. Misra U, Pridie AK, McClymont C et al- Plasma concentrations of bupivacaine following combined sciatic and femoral 3 in 1 nerve blocks in open knee surgery. Br J Anaesth, 1991;66:310-313.
13. Palve H, Kirvela O, Olin H et al - "Maximum recommended doses" of lignocaine are not toxic. Br J Anaesth, 1995;74: 704-705.
14. Imbelloni LE, Pinto AL, Neumann CR - Bloqueio do plexo braquial pela via transarterial com altas doses de lidocaína a 1,6%. Rev Bras Anestesiol, 1989;39: 273-276.
Dra. Lúcia Beato, TSA