Multiple nerve stimulation (MNS) has been shown to result in faster onset and more frequent success for axillary and humeral blocks (HB) as opposed to single injection techniques (1). However, MNS requires withdrawal and redirection of the stimulating needle and may cause more discomfort than a single injection block. Only three recent studies directly compared overall discomfort of both blocks (2–4). However, these studies were performed in scheduled orthopedic patients; no information is available in trauma patients in whom regional anesthesia techniques are regularly used; this despite the fact that fracture mobilization by electrostimulation may be painful (5,6). Both infraclavicular block (ICB) and HB provide frequent success and are associated with a similar anesthetic time, but time to perform the block is shorter and the number of nerves/trunks electrolocated is less with ICB (7,8).
The aim of this study was thus to compare ICB and HB in trauma patients using patient comfort during performance of the anesthetic procedure as the primary outcome measure, assuming that ICB would cause less pain than HB.
A prospective study was conducted on 104 patients who underwent emergency surgery on the inferior third of the humerus to the hand in a single university teaching hospital. After approval by the local Ethical Committee, all patients provided informed consent. Patients were randomized to receive ICB (group I, n = 52) or HB (group H, n = 52). Patients with any contraindication to regional anesthesia (patient's refusal, major hemostasic anomalies, or local infection), bilateral surgery, pneumonectomy, dementia, or allergic reaction to local anesthetics (LA) and pregnant women were excluded from the study. After insertion of an IV catheter in the contralateral arm, standard monitoring was applied. Sufentanil (0.1 μg/kg) was given IV 5 min before the procedure. All blocks were performed by an experienced senior anesthesiologist with a nerve stimulator (Stimuplex® HNS 11; B Braun, Malsungen, Germany) and an insulated needle (Stimuplex®, 50 mm and 22-gauge). Lidocaine 1.5% with 1:400,000 epinephrine was used in all cases. The nerve stimulator was set at 100 μs, 1.4 mA and 2 Hz. A distal and clear motor response in the hand or the wrist at a current output ranging between 0.3 and 0.5 mA was obtained in all patients.
For ICB, patients were placed supine, with the head turned away from the arm to be anesthetized as previously described (7). The forearm was placed on the abdomen. 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. Then, the needle was withdrawn 1 or 2 cm and redirected medially and posteriorly to stimulate the lateral, medial, or posterior cord and 30 mL fractionated doses with frequent aspiration of the same solution were 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 LA solution (10 mL on each nerve).
The duration of the procedure was defined as needle insertion to withdrawal. The onset of sensory block was evaluated every 5 min on the radial (posterior part of the wrist and of the 3 first fingers), median (anterior part of the wrist and of the 3 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 with the same stimulation on the contralateral arm. Rating was undertaken using the following scale: 0 = no sensation, 1 = hypoesthesia, and 2 = normal sensation. A successful block (efficacy) was defined as the absence of cold and pinprick response (score = 0) in all 4 major nerve distributions of the brachial plexus (radial, median, ulnar and musculocutaneous) within 30 min of injection of the LA solution. In group I, if one or two nerves were not blocked, selective supplementation was performed using a nerve stimulator using the humeral approach. In group H, 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. After the end of the block and before surgery started, patients identified the most unpleasant of the 4 components of the procedure: skin transfixion, needle redirections in search of the nerves, LA injection (paresthesia or dysesthesia), or electrical stimulation (pain caused by movement). Patients then quantified pain intensity on visual analog scale (VAS) of 0 to 100 for the overall procedure and for each of the 4 components. Patient satisfaction was assessed immediately after surgery in the postanesthesia care unit with a 6-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. Duration of the block was assessed. Each patient was followed up by the attendant surgeon postoperatively for several weeks to identify complications or complaints.
Before the trial, and based on the studies of Koscielniak-Nielsen et al. (3,4) as well as our own previous study comparing HB versus ICB (8), sample size was evaluated. We demonstrated that both ICB and HB are frequently successful, are associated with a similar anesthetic time, and that few differences can be demonstrated between the two techniques concerning anesthetic time (8). Koscielniak-Nielsen et al. found VAS at 30 mm for HB (3) and 10 mm for ICB (4). We assumed higher VAS as a result of upper limb trauma. A power calculation for a 30% difference in the VAS with a probability level of 0.05 and power of 0.80 (1-β) yielded a sample size of 48 patients for each group. We enrolled 52 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 percentages. χ2 test, analysis of variance, and Student's t-test were performed as appropriate. P < 0.05 was considered statistically significant.
All 104 patients completed the investigation. Demographic and surgical data are shown in Table 1. The success rate was 90% for ICB and 94% for HB (not significant). Four patients in the ICB group and two patients in group H required supplementation (not significant). General anesthesia was performed in one patient in each group. Time to perform the block was significantly shorter in group I (ICB, 6 ± 4 min versus HB, 10 ± 4 min; P < 0.0001). The onset time was 13 ± 7 min for ICB and 9 ± 3 min for HB (P < 0.05). Duration of the block was 229 ± 10 min in group I versus 230 ± 10 min in group H (not significant). In group H, a tourniquet was applied in 35 patients, 7 of whom felt a small degree of pain, although no patient needed supplementary opioids. A tourniquet was applied in 34 patients in group I and 2 of these patients felt a small degree of pain although no patient needed supplementary opioids. There were no differences in tourniquet pain.
Intensity of discomfort (VAS pain: 0–100 mm) for the block (overall procedure) was higher in group H compared with group I (35 ± 27 mm versus 19 ± 18 mm; P = 0.0011) (Table 2). More HB patients identified electrical stimulation as the most painful component of the blocking procedure (Table 2). The skin puncture was also identified as a more painful component of the HB compared with ICB (P = 0.01). However, there were no statistically significant differences between groups in pain intensities with regard to the needle redirection and LA injections.
A high degree of satisfaction (grade 4 or 5) was recorded in 93% (HB) versus 95% (ICB) of cases. Most patients (i.e., 94% [HB] versus 98% [ICB]) stated they would ask for the same regional anesthesia technique for another surgical intervention.
Venous puncture was observed in one patient in each group, but neither had clinical consequence. No other clinically significant complications, including vascular absorption of the LA, overdose, recurrent laryngeal or phrenic nerve block, residual paresthesia, Horner's syndrome, or pneumothorax, were observed.
This is the first prospective randomized study that compares ICB and HB in trauma patients with regard to patient comfort during the anesthetic procedure. The patients' pain scores were significantly higher in group H than in group I. Time to perform the block was significantly shorter in group I (ICB: 6 ± 4 minutes versus HB: 10 ± 4 minutes; P < 0.0001). The onset time was 13 ± 7 minutes for ICB and 9 ± 3 minutes for HB (P < 0.05).
Pain during arm movement caused by electrical stimulations was the main cause of discomfort during both anesthetic procedures, but pain scores can be considered clinically relevant in our trauma patients undergoing HB. Indeed, pain scores were 35 ± 27 mm in the present study and should be compared with pain scores associated with HB in patients undergoing scheduled surgery. Kinirons et al. (9), for example, found pain scores of 14 ± 12 mm, although these VAS scores were obtained in patients sedated with midazolam and sufentanil. This discrepancy might also be explained by a shorter performance time (5.7 ± 0.2 minutes versus 10 ± 4 minutes) recorded in the study by Kinirons et al. (9), which might indicate a reduced number of needle passes required to perform the block. However, Sia at al. (2) found pain scores of 23 ± 12 mm for HB with a performance time similar to ours (8 ± 2 minutes). Even if ICB was more painful than previously described (10 mm versus 19 mm), there were no substantial differences between this study and ours in regard to pain intensities of the 3 components of the block: repeated needle passes: 10 mm versus 14 mm, LA injections: 10 mm versus 7 mm, electrical stimulation: 15 mm versus 15 mm (4).
Differences in pain scores between ICB and HB in our trauma patients might be explained by the difference in block performance times (ICB, 6 ± 4 minutes versus HB, 10 ± 4 minutes). Moreover, ICB uses a simpler technique (i.e., a reduced number of arm movements), which may explain the lower VAS scores with ICB in trauma patients. Withdrawal and redirection of the stimulating needle to elicit four different muscular twitches indeed increases patient discomfort as well as the time to perform the HB (10) and increases pain at the fracture site induced by muscle contractions. A previous experience with a regional technique is a significant factor in acceptance of a regional technique for future surgery. Fear of needle puncture has been cited as a major cause for patient dissatisfaction or refusal of regional anesthesia (11). In a review of patient satisfaction after regional anesthesia, needle puncture was the greatest negative factor associated with the technique and pain after needle puncture was the most commonly reported complication (12). The procedure time required during MNS is longer than with a single electrolocation technique (13), and thus muscle contractions and needle movements experienced may increase both patient discomfort and pain. Thus, IV sedatives are frequently administered before MNS block to decrease pain and discomfort and improve patient acceptance (9). Kinirons et al. (9) reported that sedation should be administered in patients who are anxious or who demonstrate needle phobia or in trauma patients in whom MNS may be painful.
The success rate was high and not significantly different between the 2 groups (90% versus 94%) and was similar to that recorded in our previous study (7). Bouaziz et al. (14) showed that the HB results in more frequent success than a conventional axillary approach, suggesting that a four injection technique results in more frequent success than two injections. Sia et al. (2) compared a four injection HB to a four injection axillary block and found similar success rates. We, however, found similar success rates when comparing a two injection technique (i.e., ICB) to a four injection technique (i.e., HB) (8).
In conclusion, ICB is a useful technique with a high success rate similar to the midhumeral approach that is associated with a decreased block performance time and less pain during the procedure. It is thus preferred over the midhumeral approach in patients with upper limb trauma.
1. Koscielniak-Nielsen ZJ, Stens-Pedersen HL, Lippert Knudsen F. Readiness for surgery after axillary block: single versus multiple injections. Eur J Anaesthesiol 1997;14:164–71.
2. Sia S, Lepri A, Campolo MC, Fiaschi R. Four-injection brachial plexus block using peripheral nerve stimulator: a comparison between axillary and midhumeral approaches. Anesth Analg 2002;95:1075–9.
3. Koscielniak-Nielsen ZJ, Rasmussen H, Nielsen PT. Patients' perception of pain during axillary and humeral blocks using multiple nerve stimulations. Reg Anesth Pain Med 2004;29:328–32.
4. Koscielniak-Nielsen ZJ, Rasmussen H, Hesselbjerg L, et al. Infraclavicular block causes less discomfort than axillary block in ambulatory patients. Acta Anaesthesiol Scand. 2005;49:1030–4.
5. Fuzier R, Tissot B, Mercier-Fuzier V, et al. Evaluation of regional anesthesia procedure in an emergency department. Ann Fr Anesth Réanim 2002;21:193–7.
6. Laxenaire MC, Auroy Y, Clergue F, et al. Anesthetics for emergencies. Ann Fr Anesth Réanim 1998;17:1352–62.
7. Minville V, N′Guyen L, Chassery C, et al. A modified coracoid approach to infraclavicular brachial plexus blocks using a double-stimulation technique in 300 patients. Anesth Analg. 2005;100:263–5.
8. Minville V, Amathieu R, Nguyen L, et al. Infraclavicular brachial plexus block versus humeral approach: comparison of anesthetic time and efficacy. Anesth Analg 2005;101:1198–201.
9. Kinirons BP, Bouaziz H, Paqueron X, et al. Sedation with sufentanil and midazolam decreases pain in patients undergoing upper limb surgery under multiple nerve block. Anesth Analg 2000;90:1118–21.
10. Fanelli G, Casati A, Garancini P, Torri G. Nerve stimulator and multiple injection technique for upper and lower limb blockade: failure rate, patient acceptance, and neurologic complications. Anesth Analg 1999;88:847–52.
11. Gajraj NM, Sharma SK, Souter AJ, et al. A survey of obstetric patients who refuse regional anaesthesia. Anaesthesia 1995;50:740–1.
12. De Andres J, Valia JC, Gil A, Bolinches R. Predictors of patient satisfaction with regional anesthesia. Reg Anesth 1995;20:498–505.
13. Koscielniak-Nielsen ZJ, Stens-Pendersen HL, Lippert FK. Readiness for surgery after axillary block: single or multiple injection techniques. Eur J Anaesth 1997;14:154–71.
14. Bouaziz H, Narchi P, Mercier FJ, et al. Comparison between conventional axillary block and a new approach at the midhumeral level. Anesth Analg 1997;84:1058–62.