Imad T. Awad

Ultrasound reduces the minimum effective local anaesthetic volume compared with peripheral nerve stimulation for interscalene block

BACKGROUND Previous studies have demonstrated that lower local anaesthetic (LA) volumes can be used for ultrasound (US)-guided interscalene brachial plexus block (ISB). However, no study has examined whether US can reduce the volume required when compared with nerve stimulation (NS) for ISB. Our aim was to do this by comparing the minimum effective analgesic volumes (MEAVs). METHODS After ethics approval and informed consent, patients undergoing shoulder surgery were recruited to this randomized, double-blind, up-down sequential allocation study. The volume used for both US and NS was dependent upon the success or failure of the previous block. Success was defined as a verbal rating score of 0/10, 30 min after surgery. Ten needle passes were allowed before defaulting to the opposite group. Patients received general anaesthesia. Pain scores and analgesic consumption were assessed by a blinded observer. Statistical comparisons of continuous variables were performed using Students t-test and Mann-Whitney U-test as appropriate. Categorical variables were analysed using χ² test. MEAV values were estimated using log-transformed up-down independent pairs analysis and probit regression. Significance was assumed at P<0.05 (two-sided). RESULTS The MEAV required to provide effective analgesia was significantly (P=0.034) reduced to 0.9 ml [95% confidence interval (CI) 0.3-2.8] in the US group from 5.4 ml (95% CI 3.4-8.6) in the NS group. Fewer needle passes were needed to identify the brachial plexus with US (1 vs 3; P<0.0001) and patients had less pain at 30 min after surgery (P=0.03). CONCLUSIONS US reduces the number of attempts, LA volume, and postoperative pain when compared with NS for ISB.

Perioperative gabapentin reduces 24 h opioid consumption and improves in-hospital rehabilitation but not post-discharge outcomes after total knee arthroplasty with peripheral nerve block

BACKGROUND This study was designed to determine whether a 4 day perioperative regimen of gabapentin added to celecoxib improves in-hospital rehabilitation and physical function on postoperative day 4 and 6 weeks and 3 months after total knee arthroplasty (TKA). METHODS After Research Ethics Board approval and informed consent, 212 patients were enrolled in a randomized, double-blinded, placebo-controlled study. Two hours before surgery, patients received celecoxib 400 mg p.o. and were randomly assigned to receive either gabapentin 600 mg or placebo p.o. Two hours later, patients received femoral, sciatic nerve blocks, and spinal anaesthesia. After operation, patients received gabapentin 200 mg or placebo three times per day (TID) for 4 days. All patients also received celecoxib 200 mg q12 h for 72 h and i.v. patient-controlled analgesia for 24 h. Pain and function were assessed at baseline, during hospitalization, on postoperative day 4 (POD4), and 6 weeks and 3 months after surgery. RESULTS The gabapentin group used less morphine in the first 24 h after surgery [G=38.3 (29.5 mg), P=48.2 (29.4 mg)] (P<0.0125) and had increased knee range of motion compared with the placebo group in-hospital (P<0.05). There were no differences between groups in favour of the gabapentin group for pain or physical function on POD 4 [95% confidence interval (CI): pain: -1.4, 0.5; function: -6.3, 2.0], 6 weeks (95% CI: pain: 0.1, 1.9; function: -0.2, 6.5) or 3 months (95% CI: pain: -0.2, 1.7; function: -2.2, 4.3) after TKA. CONCLUSIONS In the context of celecoxib, spinal anaesthesia, femoral and sciatic nerve blocks, a dose of gabapentin 600 mg before operation followed by 4 days of gabapentin 200 mg TID decreased postoperative analgesic requirements and improved knee range of motion after TKA. Gabapentin provided no improvement in pain or physical function on POD4 and 6 weeks or 3 months after surgery.

The creation of an objective assessment tool for ultrasound-guided regional anesthesia using the Delphi method.

Background and Objectives The assessment of technical skills in ultrasound-guided regional anesthesia is currently subjective and relies largely on observations of the trainer. The objective of this study was to develop a checklist to assess training progress and to detect training gaps in ultrasound-guided regional anesthesia using the Delphi method. Methods A 30-item checklist was developed and then e-mailed to 18 reviewers for feedback. The checklist was modified on the basis of their feedback. This process of iteration was repeated until no further feedback was received, and a consensus was reached on the final composition of the checklist. A global rating scale (GRS) was introduced as a result of the feedback. Results Three rounds of feedback were required to reach consensus on the composition of the checklist and the GRS. The final checklist contains 22 items, and the GRS contains 9 categories. Conclusions Using the Delphi method, a checklist and GRS were developed. These tools can serve as an objective means of assessing progress in ultrasound technical skills acquisition.

A Scoping Review of the Evidence for Teaching Ultrasound-Guided Regional Anesthesia

Abstract A scoping review was performed to assess published evidence regarding how best to teach ultrasound-guided regional anesthesia (UGRA). The literature search yielded 205 articles, of which 35 met the inclusion criteria. Current literature on the topic can be divided into 3 main themes: the development of motor skills, learning and teaching sonoanatomy, and understanding of the requirements for establishing a UGRA education program and evaluation. We discuss the current status and future direction of research on UGRA training.

Pregabalin reduces postoperative opioid consumption and pain for 1 week after hospital discharge, but does not affect function at 6 weeks or 3 months after total hip arthroplasty

BACKGROUND This study examined whether a perioperative regimen of pregabalin added to celecoxib improved pain scores and functional outcomes postdischarge up to 3 months after total hip arthroplasty (primary outcome) and acute postoperative pain and adverse effects (secondary outcomes). METHODS One hundred and eighty-four patients were enrolled in a randomized, double-blind, placebo-controlled study. Two hours before receiving a spinal anaesthetic and undergoing surgery, patients received celecoxib 400 mg p.o. and were randomly assigned to receive either pregabalin 150 mg p.o. or placebo p.o. After surgery, patients received pregabalin 75 mg or placebo twice daily in hospital and for 7 days after discharge. Patients also received celecoxib 200 mg every 12 h for 72 h and morphine i.v. patient-controlled analgesia for 24 h. Pain and function were assessed at baseline, 6 weeks, and 3 months after surgery. RESULTS There was no difference between groups in physical function or incidence and intensity of chronic pain 3 months after total hip arthroplasty. The pregabalin group used less morphine [mean (sd): 39.85 (28.1) mg] than the placebo group [54.01 (31.2) mg] in the first 24 h after surgery (P<0.01). Pain scores were significantly lower in the pregabalin group vs the placebo group on days 1-7 after hospital discharge, and the pregabalin group required less adjunctive opioid medication (Percocet) 1 week after hospital discharge (P<0.05). CONCLUSIONS Perioperative administration of pregabalin did not improve pain or physical function at 6 weeks or 3 months after total hip arthroplasty. Perioperative administration of pregabalin decreased opioid consumption in hospital and reduced daily pain scores and adjunct opioid consumption for 1 week after discharge.

Ultrasound-guided blocks for shoulder surgery.

Purpose of review There have been several recent insights in our understanding of how best to provide optimal perioperative anesthesia and analgesia for ambulatory shoulder surgery. This review attempts to distill the advances reported in the past 12–18 months and put them in perspective. Recent findings Recent studies have explored the optimal dosing regimens and techniques for single-shot and continuous nerve blocks with regard to block effectiveness and complications. Further rigorously conducted studies into postoperative neurological and respiratory complications are correlated with study findings of brachial plexus anatomy. Evidence is presented supporting supraclavicular brachial plexus block as an equivalent alternative to interscalene block for ambulatory shoulder surgery. Summary Following recent findings it is likely that the use of supraclavicular block will become more popular for shoulder surgery. However, further large-scale trials will be needed to definitively prove its advantages over the traditional interscalene block. On the contrary, the precision of ultrasound guidance and the ongoing optimization of postoperative continuous anesthetic infusion regimens continue to improve the performance characteristics of interscalene block.

Maintaining micturition in the perioperative period: strategies to avoid urinary retention.

Purpose of review Maintaining micturition in the perioperative period can be challenging because of its low profile, other competing clinical criteria, poorly defined diagnostic criteria, and varying management strategies. Postoperative urinary retention, the main complication of micturition difficulties, has clinical implications in terms of perioperative outcome such as delayed discharge, iatrogenic infection from catheterization with the potential risk of systemic infection, and possible long-term bladder dysfunction. Factors contributing to postoperative micturition problems are multifactorial and anesthesiologists should consider the strategies to minimize the incidence of postoperative urinary retention. Recent findings Several factors have been identified as increasing the risk of perioperative micturition difficulties including medical comorbidities, surgical type, anesthetic type, and within anesthetic type specific agents such as long-acting neuraxial opioids. Current literature indicates that long-term sequelae are unlikely, with bladder overdistension lasting less than 4 h. Summary Employing strategies aimed at minimizing the disruptions in bladder function can mitigate perioperative micturition problems and subsequent complications. This requires a multifactorial approach. We present identified risk factors, considerations for their modification, as well as a classification and management strategy that incorporates the literature to date.

A comparison of sartorius versus quadriceps stimulation for femoral nerve block: a prospective randomized double-blind controlled trial.

BACKGROUND:Femoral nerve block is widely used for regional anesthesia and analgesia in many lower limb operations. Peripheral nerve stimulation of the femoral nerve may elicit 1 of 2 responses: contraction of the sartorius muscle through stimulation of its muscular branch or contraction of the quadriceps muscle through stimulation of its respective muscular branches. Historically, a quadriceps response has been preferred. We hypothesized that the success of femoral nerve block using a sartorius muscle evoked motor response is equivalent to that using quadriceps muscle twitch response. This prospective randomized double-blind controlled trial compared sartorius or quadriceps muscle evoked motor response as the end point for stimulation for femoral nerve block. METHODS:Seventy-two patients scheduled for primary unilateral total knee arthroplasty were randomly assigned to undergo femoral nerve block using either the sartorius or the quadriceps evoked muscle response as an end point of stimulation. Motor block of the femoral and sensory block of the femoral, saphenous, and lateral femoral cutaneous nerves were assessed. The primary outcome was the quality of motor and sensory block of the femoral nerve 30 minutes after injection of 20 mL of 0.5% ropivacaine. Secondary outcomes were duration of femoral nerve block, time required to perform the nerve block, total dose of hydromorphone patient-controlled analgesia, and postoperative pain by visual analog score 24 hours after block insertion. In addition, the spread of local anesthetic and the position of the needle in relation to the femoral nerve were assessed by means of ultrasonography. RESULTS:There were no statistically significant differences in the proportion of patients with either complete alone or complete and partial block combined between quadriceps and sartorius groups 30 minutes after block insertion; femoral nerve (P = 0.49; P = 0.13), the saphenous nerve (P = 0.64; P = 0.21), or the lateral femoral cutaneous nerves (P = 0.2; P = 0.35). Patient-controlled analgesia hydromorphone consumption was significantly higher in the group that underwent sartorius muscle stimulation ([mean ± SD] 4.9 ± 3.6 mg [range, 0–13.2 mg] vs 3.1 ± 2.7 mg [range, 0–10.0 mg]; P = 0.024). CONCLUSION:Our study demonstrated that using sartorius or quadriceps evoked muscle twitch as an end point of stimulation was associated with an equivalent degree of femoral nerve block.

Posterior interscalene block: An ultrasound-guided case series and overview of history, anatomy and techniques

BACKGROUND The posterior interscalene block has been described as an alternative to the lateral interscalene block. However, this technique has not gained popularity because of the close proximity of the approach to vascular and central neural structures. OBJECTIVE To describe the posterior interscalene block technique using ultrasound imaging, and to review the history of its evolution. METHODS The use of ultrasound imaging to facilitate the insertion of interscalene catheters using the posterior approach in 11 patients undergoing total shoulder arthroplasty is described. RESULTS All 11 patients had satisfactory analgesia in the first 24 h of the postoperative period. None of the patients complained of neck pain, as had been found in earlier techniques using the posterior approach. CONCLUSIONS This modification of the posterior approach is a safe and effective method for the insertion of interscalene brachial plexus catheters. These catheters are also comfortable for patients and, in the present study, none of the catheters inadvertently fell out.

Reply to Drs Wong and Barrington.

W e read with interest the publication by Cheung et al, consisting of a consensus-backed checklist and modified global rating scale. This ‘‘objective assessment tool’’ may be the best of its kind to date and has been designed to be highly specific for the assessment of ultrasound-guided regional anesthesia. However, we suggest improvements in the following areas: (1) As outlined in a previous review on the subject, we believe that the options for the checklist should be dichotomous to be more objective. Each item is currently scored using 3 options: ‘‘not performed,’’ ‘‘performed poorly,’’ and ‘‘performed well.’’ We suggest that the scoring options be made dichotomous by combining ‘‘not performed’’ together with ‘‘performed poorly.’’ For example, consider item 3, ‘‘Choice of correct transducer,’’ and item 10, ‘‘Maintenance of needle tip during advancement of needle.’’ To make the distinction between ‘‘not performed’’ and ‘‘performed poorly’’seems either irrelevant or not applicable. (2) The needle in-plane skills (items 9Y11) are difficult to rate objectively without further definition. Where do you cross the line from ‘‘performed poorly’’ to ‘‘performed well’’ in regard to item 9, ‘‘Appropriate needle alignment’’; item 10, ‘‘Maintenance of needle tip during advancement’’; and item 11, ‘‘Efficiency of regaining needle tip’’? We have previously explored the usefulness of incorporating quality compromising behaviors into an assessment of needling skills, and there may be a role for incorporating a similar or shortened version of these quality compromising behaviors into the needle alignment items. For example, some reference could be made to the lack of obvious errors (eg, ‘‘infrequently’’ advancing the needle without the tip seen). Otherwise, these subjective items may poorly discriminate between trainees. (3) Items 19 and 20 (needle tip positioning during injection) are possibly redundant and almost identical to items 10 and 11 (needle tip positioning during advancement). There may also be some redundancy among the global rating scale items, ‘‘Time and motion’’ versus ‘‘Instrument handling’’ and ‘‘Flow of procedure’’ versus ‘‘Knowledge of procedure.’’ These items may be difficult to separate because of their wording. (4) ‘‘Overall should the candidate pass or fail’’ appears subjective. Perhaps the wording could be: ‘‘Would you be happy (or would it be safe) to let the candidate perform the next procedure unsupervised (or with minimal supervision)?’’