Éric Albrecht

The analgesic efficacy of local infiltration analgesia vs femoral nerve block after total knee arthroplasty: a systematic review and meta-analysis

Many consider femoral nerve block the gold standard in pain management following knee arthroplasty. Local infiltration analgesia is an alternate approach that applies the concept of surgical wound infiltration with local anaesthetics. This meta-analysis aims to compare both analgesic treatments for analgesia and functional outcomes after total knee arthroplasty. This meta-analysis was performed according to the PRISMA statement guidelines. The primary outcomes were cumulative i.v. morphine consumption, pain scores at rest and on movement on postoperative day one (analogue scale,0-10). Secondary outcomes included range of motion, quadriceps muscle strength, length of stay and rates of complications (neurologic events, cardiovascular events, falls and knee infections). Fourteen trials, including 1122 adult patients were identified. There was no difference in i.v. morphine consumption (mean difference: -2.0 mg; 95% CI: -4.9, 0.9 mg; I(2)=69%; P=0.19), pain scores at rest (mean difference: -0.1; 95% CI: -0.4, 0.3; I(2)=72%; P=0.80) and pain scores on movement (mean difference: 0.2; 95% CI: -0.5, 0.8; I(2)=80%; P=0.64) on postoperative day one (a negative mean difference favours local infiltration analgesia). The qualities of evidence for our primary outcomes were moderate according to the GRADE system. There were no clinical differences in functional outcomes or rates of complications. Complication rates were captured by three trials or fewer with exception of knee infection, which was sought by eight trials. Local infiltration analgesia provides similar postoperative analgesia after total knee arthroplasty to femoral nerve block. Although this meta-analysis did not capture any difference in rates of complications, the low number of trials that specifically sought these outcomes dictates caution.

The analgesic efficacy of sciatic nerve block in addition to femoral nerve block in patients undergoing total knee arthroplasty: a systematic review and meta-analysis.

The aim of this meta‐analysis was to assess the postoperative analgesic efficacy of sciatic nerve block when combined with femoral nerve block after total knee arthroplasty. Outcomes included resting pain scores (analogue scale, 0–100), intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively, and functional outcomes comprising knee flexion, distance walked, and length of stay. Twelve randomised controlled trials were included, with a total of 600 patients. When combined with femoral nerve block, sciatic nerve block significantly reduced resting pain scores at 12 h postoperatively with a mean difference of 10 (95% CI: −15 to −5; p < 0.00001). Resting pain scores at 24 h, and intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively were also significantly reduced, but without clinical significance beyond 12 h and without affecting functional outcomes. In conclusion, sciatic nerve block confers additional postoperative analgesia within the first 12 postoperative hours compared with femoral nerve block alone for patients undergoing total knee arthroplasty.

Number of Edb motor units estimated using an adapted multiple point stimulation method: normal values and longitudinal studies in ALS and peripheral neuropathies

OBJECTIVE To validate the adapted multiple point stimulation (AMPS) method to estimate the number of motor units (MUNE) from the extensor digitorum brevis (Edb) muscle. METHODS Twenty controls (10 young and 10 old) were examined on both sides and 10 patients with amyotrophic lateral sclerosis (ALS) and 5 with acute peripheral neuropathy (PN) were examined longitudinally on one side during a series of repeated electrophysiological sessions. RESULTS In the controls, the median MUNE and size of the motor unit action potentials (S-MUAPs) were found to be age-related (411 and 70 microVms in the young group; 164 and 142 microVms in the old group; P < 0.01), with a coefficient of variation of MUNE values of 27% and 20%, respectively. In the ALS group, the median MUNE value at diagnosis was 31 (P < 0.05 vs. controls), and during a mean follow-up period of 11.5 months a continuous decrease in the MUNE value was seen, together with an initial increase, followed by a later decrease in 4 cases, in S-MUAP size. In the PN group, the MUNE value was initially similar to that in controls, but then decreased, accompanied by an increase in S-MUAP size, and then showed a progressive increase, together with a decrease in S-MUAP size. CONCLUSIONS AMPS, a MUNE method developed in the upper extremity, also appears to be a useful procedure for quantifying changes in the MUNE value in the Edb muscle without specific software in order to study age-related changes or changes in patients with ALS or PN.

A systematic review of ultrasound-guided methods for brachial plexus blockade†

We systematically reviewed 25 randomised controlled trials of ultrasound‐guided brachial plexus blockade that recruited 1948 participants: either one approach vs another (axillary, infraclavicular or supraclavicular); or one injection vs multiple injections. There were no differences in the rates of successful blockade with approach, relative risk (95% CI): axillary vs infraclavicular, 1.0 (1.0–1.1), p = 0.97; axillary vs supraclavicular, 1.0 (1.0–1.1), p = 0.68; and infraclavicular vs supraclavicular, 1.0 (1.0–1.1), p = 0.32. There was no difference in the rate of successful blockade with the number of injections, relative risk (95% CI) 1.0 (1.0–1.0), p = 0.69, for one vs multiple injections. The rate of procedural paraesthesia was less with one injection than multiple injections, relative risk (95% CI) 0.6 (0.4–0.9), p = 0.004.

Efficacy of perineural vs systemic dexamethasone to prolong analgesia after peripheral nerve block: a systematic review and meta-analysis

Perineural dexamethasone has gained popularity in regional anaesthesia to prolong the duration of analgesia, but its advantage over systemic administration is disputed. The objective of this meta-analysis was to compare the analgesic efficacy of both routes of administration during peripheral nerve block. The methodology followed the PRISMA statement guidelines. The primary outcome was the duration of analgesia analysed according to the type of local anaesthetic administered (bupivacaine or ropivacaine). Secondary outcomes included cumulative opioid consumption in morphine i.v. equivalents, pain scores, and complication rates (neurological complications, infection, or hyperglycaemia). Eleven controlled trials, including 914 patients, were identified. The duration of analgesia was significantly increased with perineural dexamethasone vs systemic dexamethasone by a mean difference of 3 h [95% confidence interval (CI): 1.4, 4.5 h; P=0.0001]. Subgroup analysis revealed that the duration of analgesia was increased by 21% with bupivacaine (mean difference: 4.0 h; 95% CI: 2.8, 5.2 h; P<0.00001) and 12% with ropivacaine (mean difference: 2.0 h; 95% CI: -0.5, 4.5 h; P=0.11). The quality of evidence for our primary outcome was moderate according to the GRADE system. There were no significant differences in other secondary outcomes. No neurological complications or infections were reported. Glucose concentrations were not increased when dexamethasone was injected systemically, but this outcome was reported by only two trials. There is, therefore, moderate evidence that perineural dexamethasone combined with bupivacaine, but not ropivacaine, slightly prolongs the duration of analgesia, without an impact on other pain-related outcomes, when compared with systemic dexamethasone. Injection of perineural dexamethasone should be cautiously balanced in light of the off-label indication for this route of administration.

Extrafascial injection for interscalene brachial plexus block reduces respiratory complications compared with a conventional intrafascial injection: a randomized, controlled, double-blind trial

BACKGROUND Hemidiaphragmatic paresis after ultrasound-guided interscalene brachial plexus block is reported to occur in up to 100% of patients. We tested the hypothesis that an injection lateral to the brachial plexus sheath reduces the incidence of hemidiaphragmatic paresis compared with a conventional intrafascial injection, while providing similar analgesia. METHODS Forty ASA I-III patients undergoing elective shoulder and clavicle surgery under general anaesthesia were randomized to receive an ultrasound-guided interscalene brachial plexus block for analgesia, using 20 ml bupivacaine 0.5% with epinephrine 1:200 000 injected either between C5 and C6 within the interscalene groove (conventional intrafascial injection), or 4 mm lateral to the brachial plexus sheath (extrafascial injection). The primary outcome was incidence of hemidiaphragmatic paresis (diaphragmatic excursion reduction >75%), measured by M-mode ultrasonography, before and 30 min after the procedure. Secondary outcomes were forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow. Additional outcomes included time to first opioid request and pain scores at 24 h postoperatively (numeric rating scale, 0-10). RESULTS The incidences of hemidiaphragmatic paresis were 90% (95% CI: 68-99%) and 21% (95% CI: 6-46%) in the conventional and extrafascial injection groups, respectively (P<0.0001). Other respiratory outcomes were significantly better preserved in the extrafascial injection group. The mean time to first opioid request was similar between groups (conventional: 802 min [95% CI: 620-984 min]; extrafascial: 973 min [95% CI: 791-1155 min]; P=0.19) as were pain scores at 24 h postoperatively (conventional: 1.6 [95% CI: 0.9-2.2]; extrafascial: 1.6 [95% CI: 0.8-2.4]; P=0.97). CONCLUSIONS Ultrasound-guided interscalene brachial plexus block with an extrafascial injection reduces the incidence of hemidiaphragmatic paresis and impact on respiratory function while providing similar analgesia, when compared with a conventional injection. CLINICAL TRIAL REGISTRATION NCT02074397.

A two-year retrospective review of the determinants of pre-hospital analgesia administration by alpine helicopter emergency medical physicians to patients with isolated limb injury†

Up to 75% of pre‐hospital trauma patients experience moderate to severe pain but this is often poorly recognised and treated with insufficient analgesia. Using multi‐level logistic regression analysis, we aimed to identify the determinants of pre‐hospital analgesia administration and choice of analgesic agent in a single helicopter‐based emergency medical service, where available analgesic drugs were fentanyl and ketamine. Of the 1156 patients rescued for isolated limb injury, 657 (57%) received analgesia. Mean (SD) initial pain scores (as measured by a numeric rating scale) were 2.8 (1.8), 3.3 (1.6) and 7.4 (2.0) for patients who did not receive, declined, and received analgesia, respectively (p < 0.001). Fentanyl as a single agent, ketamine in combination with fentanyl and ketamine as a single agent were used in 533 (84%), 94 (14%) and 10 (2%) patients, respectively. A high initial on‐scene pain score and a presumptive diagnosis of fracture were the main determinants of analgesia administration. Fentanyl was preferred for paediatric patients and ketamine was preferentially administered for severe pain by physicians who had more medical experience or had trained in anaesthesia.

Analgesic efficacy of local infiltration analgesia vs. femoral nerve block after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Many published reports consider blockade of the femoral nerve distribution the best available analgesic treatment after anterior cruciate ligament reconstruction. However, some argue that an alternative approach of infiltrating local anaesthetic into the surgical site has similar efficacy. The objectives of this meta‐analysis were to compare the analgesic and functional outcomes of both treatments following anterior ligament reconstruction. The primary outcomes were pain scores at rest (analogue scale, 0–10) in the early (0–2 postoperative hours), intermediate (3–12 hours) and late postoperative periods (13–24 hours). Secondary outcomes included range of motion, quadriceps muscle strength and complication rates (neurological problems, cardiovascular events, falls and knee infections). Eleven trials, including 628 patients, were identified. Pain scores in the early, intermediate and late postoperative periods were significantly lower in patients who received a femoral nerve block, with mean differences (95%CI) of 1.6 (0.2–2.9), p = 0.02; 1.2 (0.4–1.5), p = 0.002; and 0.7 (0.1–1.4), p = 0.03 respectively. The quality of evidence for our primary outcomes was moderate to high. Regarding functional outcomes, only one trial reported a similar range of motion between groups at 48 postoperative hours. No trial sought to record complications. In conclusion, femoral nerve block provides superior postoperative analgesia after anterior cruciate ligament reconstruction to local infiltration analgesia. The impact of improved analgesia on function remains unclear due to the lack of reporting of functional outcomes in the existing literature.

Electrophysiological Study of Femoral Nerve Function After a Continuous Femoral Nerve Block for Anterior Cruciate Ligament Reconstruction A Randomized, Controlled Single-Blind Trial

Background: A continuous femoral nerve block (CFNB) is an effective analgesic treatment after anterior cruciate ligament (ACL) reconstruction but may result in transient femoral nerve injuries and quadriceps muscle weakness, which in turn contribute to worsened functional outcomes. Purpose: To compare electrophysiological criteria of a femoral nerve injury as well as functional and pain-related outcomes after ACL reconstruction when analgesia was provided by a CFNB or intravenous patient-controlled analgesic of morphine (IV PCA). Study Design: Randomized controlled clinical trial; Level of evidence, 1. Methods: A total of 74 patients scheduled for ACL reconstruction were randomized to receive a CFNB before surgery, followed by a ropivacaine infusion for 2 days and oxycodone, or IV PCA. The primary outcome was the rate of femoral nerve injuries at 4 weeks postoperatively, defined as a reduction of the compound muscle action potential (CMAP) area from the vastus medialis muscle after supramaximal femoral nerve stimulation at the groin, associated with an absent H-reflex of the femoral nerve and signs of vastus medialis muscle denervation. Secondary functional outcomes were quadriceps muscle strength, active flexion range, and distance walked, as measured on postoperative days 1 and 2. Secondary pain-related outcomes were IV morphine consumption and pain scores at rest and on movement in phase 1 recovery and on postoperative days 1 and 2. Results: No patients met the electrophysiological criteria of a femoral nerve injury. The mean CMAP area at 4 weeks was equivalent in both the CFNB and IV PCA groups (47 ± 16 mV·ms and 51 ± 13 mV·ms, respectively; P = .50). While no differences were detected in functional outcomes or pain scores, the consumption of an IV morphine equivalent was reduced by the administration of a CFNB in phase 1 recovery (6 ± 5 mg and 13 ± 7 mg, respectively; P = .0003), on postoperative day 1 (6 ± 7 mg and 19 ± 17 mg, respectively; P = .0005), and on postoperative day 2 (11 ± 10 mg and 19 ± 17 mg, respectively; P = .03) compared with an IV PCA. Conclusion: Despite prior contrary reports, a CFNB did not result in femoral nerve injuries or worsened functional outcomes after ACL reconstruction. The improvement of analgesia with a CFNB was only marginal and not clinically relevant beyond 24 hours. Registration: NCT01321138 (ClinicalTrials.gov identifier).

Lipid emulsion layering in extracorporeal membrane oxygenation circuit

Intravenous lipid emulsion is indicated in the treatment of local anesthetic systemic toxicity or management of lipophilic drug intoxications, including tricyclic antidepressants and calcium channel blockers when patients develop malignant arrhythmias. If lipid administration is unsuccessful, guidelines recommend extracorporeal membrane oxygenation (ECMO) until clearance of the responsible toxic agent is achieved. Layering is a phenomenon that results when the separation of intact fat emulsion from blood occurs in vitro within the ECMO circuit. Administering lipid emulsion is not without risk and may result in a circuit obstruction by fat emulsion agglutination, malfunction of the membrane oxygenator, and increased risk of blood clot formation. Layering is demonstrated in a patient placed under ECMO after administration of 20 mL/kg of lipid emulsion over a 60-min period for treatment of toxicity from ingestion of 10 g of Aconitum napellus, a toxic mid-altitude wild plant (Fig. 1). Administration of lipid emulsion is not without risk and the total dose should probably not exceed 10 mL/kg as layering in the ECMO or other complications may occur and jeopardize resuscitation.