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*Department of Anesthesiology and Intensive Care, Toulouse University Hospital, Paul Sabatier University, Toulouse, France;
Department of Anesthesiology and Intensive Care, Bicêtre University Hospital, Le Kremlin-Bicêtre, France
Address correspondence and reprint requests to Vincent Minville, MD, Department of Anesthesiology and Intensive Care University Hospital of Toulouse, Toulouse, France. Address e-mail to vincentminville{at}yahoo.fr.
| Abstract |
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| Introduction |
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The aim of this study was thus to compare ICB using a double stimulation to the four-stimulation HB using the anesthetic time as a primary outcome measure.
| Methods |
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For ICB, as previously described, (4) patients were placed supine, with the head turned away from the arm to be anesthetized. The forearm was gently placed on the abdomen. Landmarks, i.e., the clavicle and the coracoid process, were easily palpated in all patients. The puncture site was located 1 cm under the clavicle, and 1 cm medially to the coracoid process. After antiseptic preparation of the area, the insulated needle was inserted in the direction of the top of the axillary fossa (in relation to the axillary artery) with an angle of 45° to locate the musculocutaneous nerve. Ten mL of lidocaine was injected with repeated aspiration tests to minimize the risk of unrecognized intravascular injection. Then, the needle was withdrawn 1 or 2 cm and redirected medially and posteriorly. A satisfactory response was defined as a distal and clear motor response in the hand or the wrist (lateral, medial or posterior cord) for a stimulating intensity ranging between 0.3 and 0.5 mA. (8) Thirty milliliters of the same local anesthetic solution was then slowly injected.
The HB was performed in a supine position with the upper arm abducted not more than 90° and the elbow flexed at 110°. After antiseptic preparation of the area, the axillary artery was palpated at the junction of the proximal and the middle third of the arm. The four nerves (median, ulnar, radial, and musculocutaneous) originating from the brachial plexus were located in the humeral canal with a nerve stimulator and blocked using the same local anesthetic solution (10 mL on the radial, ulnar, and median nerves, 8 mL on the musculocutaneous nerve, and 2 mL for the brachial and antebrachial cutaneous nerves).
The duration of the procedure was measured from needle insertion to withdrawal. The onset of sensory block (from the end of block performance to the time when all four branches of the brachial plexus block distally achieved analgesia) was evaluated every 5 min on the radial (posterior part of the wrist and of the three first fingers), median (anterior part of the wrist and of the three first fingers), ulnar (medial part of the wrist and of the hand), musculocutaneous (lateral part of the forearm), axillary (shoulder), medial brachial and antebrachial cutaneous (medial part of the arm and of the forearm) nerve territories using cold and pinprick test and then compared to the same stimulation on the contralateral arm. Rating was undertaken by using the following scale: 0 = no sensation, 1 = hypoesthesia, and 2 = normal sensation. Motor block was assessed every 5 min on the radial (thumb abduction), median (third finger flexion), ulnar (fifth finger flexion), musculocutaneous (elbow flexion), and axillary (arm abduction) nerves and then compared to the contralateral arm. Rating was performed by using the following scale: 5 = normal muscle strength, 4 = slightly reduced muscle strength, 3 = significant muscle strength reduction, 2 = only minimal muscle contraction possible (inability to move against gravity), 1 = complete paralysis. A successful block (efficacy) was defined as the absence of cold and pinprick response (score = 0) in all 4 major nerves distributions of the brachial plexus (radial, median, ulnar, and musculocutaneous), within 30 min after injection of the local anesthetic solution. In the ICB group, if one or two nerves were not blocked, selective supplementation was performed using a nerve stimulator using the humeral puncture site. In the HB group, if one or two nerves were not blocked, supplementation at the elbow was performed using a nerve stimulator. If more than two nerves remained unblocked, general anesthesia was performed in either group. Immediate and late complications were noted after the procedure. Patient satisfaction was assessed immediately after surgery in the postanesthesia care unit with a 5-point scale (from 0 = dissatisfied to 5 = very satisfied). Patients were questioned as to which anesthetic method (same regional anesthesia technique or general anesthesia) they would choose for future surgery. Each patient was followed-up by the attendant surgeon postoperatively for several weeks to identify complications or complaints.
For the estimation of the sample size, we assumed that a 20% difference in the total anesthetic time would be considered clinically important. To compare the two groups with a ß error of 20% at a significance level
of 5%, the sample size required was 45 patients in each group. We enrolled 60 patients to allow for dropouts. Statistical analyses were performed using the StatView® software (version 5.0; SAS, Cary, NC). Data are presented as mean ± sd or percentage. A
2 test, analysis of variance, or a Students t-test was performed when appropriate. P < 0.05 was considered statistically significant.
| Results |
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A high degree of satisfaction (grade 4 or 5) was recorded in 95% (HB) versus 100% (ICB) of cases. Most patients (HB 97% versus ICB 100%) stated they would ask for the same regional anesthesia technique for a similar surgical intervention.
Venous puncture was observed in one patient in each group but neither had clinical consequence. No other clinical complications, including vascular absorption of the local anesthetic, overdose, recurrent laryngeal or phrenic nerve block, residual paresthesia, Horners syndrome, or pneumothorax, were observed.
| Discussion |
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Whatever the definition, decreasing anesthesia controlled time may improve the global OR turnover time, (9) which is an important challenge for the OR manager. In addition, performing blocks in the preanesthetic area (before OR entry) should also save valuable OR time. In our study, total anesthetic time was not statistically different between groups. However, the time to perform the block was shorter in the ICB group than in the HB group. The 5-minute difference is likely to be clinically important for both patients and busy anesthesiologists. A simpler technique using a reduced number of arm movements might be desirable, especially in trauma patients, and probably explains the significant satisfaction rate with ICB (100%). Withdrawal and redirection of the stimulating needle to elicit four different muscular twitches indeed increases patient discomfort as well as the duration of block performance with HB (10) and increases pain at the fracture site induced by muscle contractions. It is also likely that the shorter the time to perform a highly efficient block, the greater the patients confidence in regional anesthesia, explaining why all patients who had ICB would prefer to receive the same technique in the future. Moreover, after the block has been performed (and during block onset), the anesthesiologist is available to perform another procedure in a nearby area.
A difference in onset time was found between groups. A comparison with times recorded by other authors is difficult because different local anesthetics solutions were used in the various studies. The longer onset time in the ICB group could be attributed to the more proximal approach of the nerves (cords), whereas HB is associated with a more peripheral approach to the four nerves. The shorter onset time in the HB group might also have been attributable to the fact that each nerve is individually identified and blocked. Shortening the ICB onset time would be useful, as this would decrease anesthetic time.
The success rate was frequent and not different between the 2 groups (92% versus 95%). Comparison of techniques should thus now be made on other criteria. Anesthetic time is a particularly useful criterion for a busy unit, but several other factors could influence the technique chosen. Ease of training is an important consideration and it is expected that a 2-stimulation technique (i.e., ICB) would be associated with a steeper learning curve than a 4-stimulation technique. However, this remains to be demonstrated. Specific clinical conditions might also influence the technique chosen. In HB, the four nerves are anatomically separated, allowing for a selective administration of different local anesthetic solutions on the various nerves. It is therefore possible to extend the sensory block duration in one or several nerves of the brachial plexus to provide postoperative analgesia targeted to the specific nerve distribution involved in the surgical area while obtaining a complete block of the whole upper limb during surgery. (11) A selective duration of the postoperative block is a major advantage with the HB approach.
In conclusion, both ICB and HB provide frequent success and are associated with a similar anesthetic time and few differences can be demonstrated between the two techniques. As the ICB performance time is shorter, the anesthesiologists availability is increased.
| Footnotes |
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| References |
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This article has been cited by other articles:
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Q. H. De Tran, A. Clemente, J. Doan, and R. J. Finlayson Brachial plexus blocks: a review of approaches and techniques: [Les blocs du plexus brachial : compte-rendu des approches et techniques] Can J Anesth, August 1, 2007; 54(8): 662 - 674. [Abstract] [Full Text] [PDF] |
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V. Minville, O. Fourcade, L. Idabouk, J. Claassen, C. Chassery, L. Nguyen, J.-C. Pourrut, and D. Benhamou Infraclavicular brachial plexus block versus humeral block in trauma patients: a comparison of patient comfort. Anesth. Analg., March 1, 2006; 102(3): 912 - 915. [Abstract] [Full Text] [PDF] |
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