Research priorities in regional anaesthesia: an international Delphi study.

BACKGROUND: Regional anaesthesia use is growing worldwide, and there is an increasing emphasis on research in regional anaesthesia to improve patient outcomes. However, priorities for future study remain unclear. We therefore conducted an international research prioritisation exercise, setting the agenda for future investigators and funding bodies. METHODS: We invited members of specialist regional anaesthesia societies from six continents to propose research questions that they felt were unanswered. These were consolidated into representative indicative questions, and a literature review was undertaken to determine if any indicative questions were already answered by published work. Unanswered indicative questions entered a three-round modified Delphi process, whereby 29 experts in regional anaesthesia (representing all participating specialist societies) rated each indicative question for inclusion on a final high priority shortlist. If ≥75% of participants rated an indicative question as 'definitely' include in any round, it was accepted. Indicative questions rated as 'definitely' or 'probably' by <50% of participants in any round were excluded. Retained indicative questions were further ranked based on the rating score in the final Delphi round. The final research priorities were ratified by the Delphi expert group. RESULTS: There were 1318 responses from 516 people in the initial survey, from which 71 indicative questions were formed, of which 68 entered the modified Delphi process. Eleven 'highest priority' research questions were short listed, covering themes of pain management; training and assessment; clinical practice and efficacy; technology and equipment. CONCLUSIONS: We prioritised unanswered research questions in regional anaesthesia. These will inform a coordinated global research strategy for regional anaesthesia and direct investigators to address high-priority areas.

Randomized clinical trial comparing pericapsular nerve group (PENG) block and periarticular local anesthetic infiltration for total hip arthroplasty.

BACKGROUND: This randomized trial compared pericapsular nerve group block and periarticular local anesthetic infiltration in patients undergoing primary total hip arthroplasty. We hypothesized that, compared with pericapsular nerve group block, periarticular local anesthetic infiltration would decrease the postoperative incidence of quadriceps weakness at 3 hours fivefold (ie, from 45% to 9%). METHODS: Sixty patients undergoing primary total hip arthroplasty under spinal anesthesia were randomly allocated to receive a pericapsular nerve group block (n=30) using 20 mL of adrenalized bupivacaine 0.50%, or periarticular local anesthetic infiltration (n=30) using 60 mL of adrenalized bupivacaine 0.25%. Both groups also received 30 mg of ketorolac, either intravenously (pericapsular nerve group block) or periarticularly (periarticular local anesthetic infiltration), as well as 4 mg of intravenous dexamethasone.Postoperatively, a blinded evaluator carried out sensory assessment and motor assessment (knee extension and hip adduction) at 3, 6 and 24 hours. Furthermore, the blinded observer also recorded static and dynamic pain scores at 3, 6, 12, 18, 24, 36 and 48 hours; time to first opioid request; cumulative breakthrough morphine consumption at 24 hours and 48 hours; opioid-related side effects; ability to perform physiotherapy at 6, 24 and 48 hours; as well as length of stay. RESULTS: There were no differences in quadriceps weakness at 3 hours between pericapsular nerve group block and periarticular local anesthetic infiltration (20% vs 33%; p=0.469). Furthermore, no intergroup differences were found in terms of sensory block or motor block at other time intervals; time to first opioid request; cumulative breakthrough morphine consumption; opioid-related side effects; ability to perform physiotherapy; and length of stay. Compared with pericapsular nerve group block, periarticular local anesthetic infiltration resulted in lower static pain scores (at all measurement intervals) and dynamic pain scores (at 3 and 6 hours). CONCLUSION: For primary total hip arthroplasty, pericapsular nerve group block and periarticular local anesthetic infiltration result in comparable rates of quadriceps weakness. However, periarticular local anesthetic infiltration is associated with lower static pain scores (especially during the first 24 hours) and dynamic pain scores (first 6 hours). Further investigation is required to determine the optimal technique and local anesthetic admixture for periarticular local anesthetic infiltration. TRIAL REGISTRATION NUMBER: NCT05087862.

Randomized comparison between perineural dexamethasone and combined perineural dexamethasone-dexmedetomidine for ultrasound-guided infraclavicular block.

BACKGROUND: This randomized trial compared perineural dexamethasone with combined perineural dexamethasone-dexmedetomidine for ultrasound-guided infraclavicular block. We hypothesized that the combination of perineural adjuvants would result in a longer motor block. METHODS: Fifty patients undergoing upper limb surgery with ultrasound-guided infraclavicular block (using 35 mL of lidocaine 1%-bupivacaine 0.25% with epinephrine 5 µg/mL) were randomly allocated to receive perineural dexamethasone (2 mg) or combined perineural dexamethasone (2 mg)-dexmedetomidine (50 µg). After the performance of the block, a blinded observer assessed the success rate (defined as a minimal sensorimotor composite score of 14 out of 16 points at 30 min), the onset time (defined as the time required to reach a minimal composite score of 14 points) as well as the incidence of surgical anesthesia (defined as the ability to complete surgery without local infiltration, supplemental blocks, intravenous opioids or general anesthesia).Postoperatively, the blinded observer contacted patients with successful blocks to inquire about the duration of motor block, sensory block and postoperative analgesia. RESULTS: No intergroup differences were observed in terms of success rate, onset time and surgical anesthesia. Compared with dexamethasone alone, combined dexamethasone-dexmedetomidine provided longer durations of motor block (21.5 (2.7) vs 17.0 (3.9) hours; p<0.001; 95% CI 2.6 to 6.4), sensory block (21.6 (3.6) vs 17.2 (3.6) hours; p<0.001; 95% CI 2.2 to 6.5), and postoperative analgesia (25.5 (9.4) vs 23.5 (5.6) hours; p=0.038; 95% CI 1.0 to 7.7). CONCLUSION: Compared with perineural dexamethasone (2 mg) alone, combined perineural dexamethasone (2 mg)-dexmedetomidine (50 µg) results in longer durations of sensorimotor block and analgesia. Further studies are required to determine the optimal dosing combination for dexamethasone-dexmedetomidine. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT04875039.

[Epidemiologic description of a post-pandemic outbreak of influenza A H1N1 2009 in an isolated community of the region of Aysén, Chilean patagonia]. / Brote comunitario de influenza A H1N1 2009 en el período post-pandémico inmediato: descripción epidemiológica en una localidad aislada de la región de Aysén, Patagonia chilena.

On August 10th 2010 the World Health Organization (WHO)announced the end of the influenza A H1N1 2009 pandemic. On August 13th, three cases of influenza A H1N1 2009 from the local school were confirmed at the Hospital de Chile Chico. An epidemiological investigation was conducted in conjunction with the regional health authority (SEREMI), in order to monitor the outbreak and establish appropriate control strategies. During the study period (august 7 to 21), 304 cases of influenza-like-illness (ILI) were reported, with an incidence of 6171 cases per 100.000 in epidemiological week no 33. Most of the affected people were 19 years old or younger (68% of cases). Hospitalized patients (n: 7) had a favorable outcome, without severe symptoms or need for transfer to an intensive care unit. A female patient with a congenital heart defect who had not been vaccinated was the only fatal case. The outstanding features of this post-pandemic outbreak were its intensity and the demonstration of the importance of control measures to prevent further spread of influenza A H1N1 2009 infections, in the community setting.

Motor-sparing nerve blocks for total knee replacement: A scoping review.

STUDY OBJECTIVE: This scoping review investigates the optimal combination of motor-sparing analgesic interventions for patients undergoing total knee replacement (TKR). DESIGN: Scoping review. INTERVENTION: MEDLINE, EMBASE and CINAHL databases were searched (inception-last week of May 2020). Only trials including motor-sparing interventions were included. Randomized controlled trials lacking prospective registration and blinded assessment were excluded. MAIN RESULTS: The cumulative evidence suggests that femoral triangle blocks outperform placebo and periarticular infiltration. When combined with the latter, femoral triangle blocks are associated with improved pain control, higher patient satisfaction and decreased opioid consumption. Continuous femoral triangle blocks provide superior postoperative analgesia compared with their single-injection counterparts. However, these benefits seem less pronounced when perineural adjuvants are used. Combined femoral triangle-obturator blocks result in improved analgesia and swifter discharge compared with femoral triangle blocks alone. CONCLUSIONS: The optimal analgesic strategy for TKR may include a combination of different analgesic modalities (periarticular infiltration, femoral triangle blocks, obturator nerve block). Future trials are required to investigate the incremental benefits provided by local anesthetic infiltration between the popliteal artery and the capsule of the knee (IPACK), popliteal plexus block and genicular nerve block.

Erector spinae plane block: A narrative review with systematic analysis of the evidence pertaining to clinical indications and alternative truncal blocks.

STUDY OBJECTIVE: This narrative review discusses the anatomy, mechanism of action, techniques, pharmacology, indications, complications and substitutes for erector spinae plane (ESP) blocks. INTERVENTIONS: The Medline, Embase and Google Scholar databases (inception-last week of April 2020) were searched. For indications and alternative blocks, a systematic analysis of the available evidence was carried out. In order to highlight the best evidence available, only randomized trials with prospective registration, blinded assessment and sample size justification were retained for analysis. MAIN RESULTS: The collective body of anatomical studies suggests that ESP block may work through a combination of different mechanisms (e.g., local anesthetic spread to the thoracic paravertebral space, epidural space, and dorsal ramus). Compared to control, the available evidence suggests that ESP block results in decreased postoperative pain and opioid requirement for a wide array of thoracic and abdominal surgical interventions. Erector spinae plane blocks and thoracic paravertebral blocks seem to provide comparable benefits for thoracoscopic and breast cancer surgery when performed with a similar number of injections. Currently, ESP blocks should be favored over intercostal blocks since, at best, the latter provide similar analgesia to ESP blocks despite requiring multiple-level injections. CONCLUSIONS: In recent years, ESP blocks have become the topic of considerable clinical interest. Future trials are required to investigate their optimal technique, dose of local anesthetic and perineural adjuvants. Moreover, additional investigation should compare ESP blocks with robust multimodal analgesic regimens as well as truncal blocks such as thoracic epidural block, midpoint transverse process to pleura block, PECS block, quadratus lumborum block, and transversus abdominis plane block.

Randomized comparison between pericapsular nerve group (PENG) block and suprainguinal fascia iliaca block for total hip arthroplasty.

BACKGROUND: This randomized trial compared ultrasound-guided pericapsular nerve group block and suprainguinal fascia iliaca block in patients undergoing primary total hip arthroplasty. We selected the postoperative incidence of quadriceps motor block (defined as paresis or paralysis of knee extension) at 6 hours as the primary outcome. We hypothesized that, compared with suprainguinal fascia iliaca block, pericapsular nerve group block would decrease its occurrence from 70% to 20%. METHODS: Forty patients undergoing primary total hip arthroplasty under spinal anesthesia were randomly allocated to receive a pericapsular nerve group block (n=20) using 20 mL of adrenalized levobupivacaine 0.50%, or a suprainguinal fascia iliaca block (n=20) using 40 mL of adrenalized levobupivacaine 0.25%. After the performance of the block, a blinded observer recorded pain scores at 3, 6, 12, 18, 24, 36, and 48 hours; cumulative breakthrough morphine consumption at 24 and 48 hours; opioid-related side effects; ability to perform physiotherapy at 24 and 48 hours; as well as length of stay. Furthermore, the blinded observer also carried out sensory assessment (of the anterior, lateral, and medial aspects of the mid-thigh) and motor assessment (knee extension and hip adduction) at 3, 6, and 24 hours. RESULTS: Compared with suprainguinal fascia iliaca block, pericapsular nerve group block resulted in a lower incidence of quadriceps motor block at 3 hours (45% vs 90%; p<0.001) and 6 hours (25% vs 85%; p<0.001). Furthermore, pericapsular nerve group block also provided better preservation of hip adduction at 3 hours (p=0.023) as well as decreased sensory block of the anterior, lateral, and medial thighs at all measurement intervals (all p≤0.014). No clinically significant intergroup differences were found in terms of postoperative pain scores, cumulative opioid consumption at 24 and 48 hours, ability to perform physiotherapy, opioid-related side effects, and length of hospital stay. CONCLUSION: For primary total hip arthroplasty, pericapsular nerve group block results in better preservation of motor function than suprainguinal fascia iliaca block. Additional investigation is required to elucidate the optimal local anesthetic volume for motor-sparing pericapsular nerve group block and to compare the latter with alternate motor-sparing strategies such as periarticular local anesthetic infiltration. TRIAL REGISTRATION NUMBER: NCT04402450.

Single- versus double-injection costoclavicular block: a randomized comparison.

BACKGROUND: The costoclavicular approach targets the brachial plexus in the proximal infraclavicular fossa, where the lateral, medial, and posterior cords are tightly bundled together. This randomized trial compared single- and double-injection ultrasound-guided costoclavicular blocks. We selected onset time as the primary outcome and hypothesized that, compared with its single-injection counterpart, the double-injection technique would result in a swifter onset. METHODS: Ninety patients undergoing upper limb surgery (at or below the elbow joint) were randomly allocated to receive a single- (n=45) or double-injection (n=45) ultrasound-guided costoclavicular block. The local anesthetic agent (35 mL of lidocaine 1%-bupivacaine 0.25%with epinephrine 5 µg/mL and 2 mg of preservative-free dexamethasone) was identical in all subjects. In the single-injection group, the entire volume of local anesthetic was injected between the three cords of the brachial plexus. In the double-injection group, the first half of the volume was administered in this location; the second half was deposited between the medial cord and the subclavian artery. After the performance of the block, a blinded observer recorded the onset time (defined as the time required to achieve a minimal sensorimotor composite score of 14 out of 16 points), success rate (surgical anesthesia) and block-related pain scores. Performance time and the number of needle passes were also recorded during the performance of the block. The total anesthesia-related time was defined as the sum of the performance and onset times. RESULTS: Compared with its single-injection counterpart, the double-injection technique displayed shorter onset time (16.6 (6.4) vs 23.4 (6.9) min; p<0.001; 95% CI for difference 3.9 to 9.7) and total anesthesia-related time (22.5 (6.7) vs 28.9 (7.6) min; p<0.001). No intergroup differences were found in terms of success and technical execution (ie, performance time/procedural pain). The double-injection group required more needle passes than the single-injection group (2 (1-4) vs 1 (1-3); p<0.001). CONCLUSION: Compared with its single-injection counterpart, double-injection costoclavicular block results in shorter onset and total anesthesia-related times. Further investigation is required to determine if a triple-injection technique (with targeted local anesthetic injection around each cord of the brachial plexus) could further decrease the onset time. TRIAL REGISTRATION NUMBER: NCT03595514.

Lumbar plexus block versus suprainguinal fascia iliaca block for total hip arthroplasty: A single-blinded, randomized trial.

STUDY OBJECTIVE: Comparison of ultrasound-guided lumbar plexus block (LPB) and suprainguinal fascia iliaca block (SIFIB) in patients undergoing total hip arthroplasty (THA). DESIGN: Randomized equivalence trial. SETTING: University Hospital. PATIENTS: Sixty patients undergoing primary THA. INTERVENTIONS: Patients were randomly allocated to receive ultrasound-guided LPB (n = 30) or SIFIB (n = 30). The local anesthetic agent (40 mL of levobupivacaine 0.25% with epinephrine 5 µg/mL) and block adjuvant (4 mg of intravenous dexamethasone) were identical in all subjects. Postoperatively, all patients received patient-controlled intravenous analgesia (morphine) as well as acetaminophen and ketoprofen during 48 h. MEASUREMENTS: A blinded investigator recorded morphine consumption at 24 and 48 h as well as time to first morphine request, pain scores at 3, 6, 12, 24 and 48 h, incidence of adverse events, time to readiness for discharge, and length of hospital stay. The blinded investigator also carried out sensorimotor block assessment at 3, 6 and 24 h using a 10-point sensorimotor composite scale. MAIN RESULTS: No intergroup differences were found in terms of cumulative morphine consumption at 24 h (95% CI: -4.0 mg to 2.0 mg) and 48 h (95% CI, -5.0 mg to 2.0 mg) or time to first morphine request. Furthermore, pain scores were similar at all time intervals after 3 h. There were no intergroup differences in terms of composite sensorimotor scores at 3 and 6 h. However, SIFIB lasted longer than lumbar plexus block as evidenced by a higher composite score at 24 h. No intergroup differences were found in terms of complications. Compared with LPB, SIFIB was associated with shorter time to readiness for discharge (3 [1-4] vs. 2 [1-3] days; P = 0.042) and length of hospital stay (3 [2-5] vs. 3 [2-4] days; P = 0.048). CONCLUSIONS: For THA, no differences were found between LPB and SIFIB in terms of breakthrough morphine requirement and pain control. However, SIFIB resulted in a longer block and was associated with shorter time to readiness for discharge as well as decreased hospital stay.

A systematic review of DURAL puncture epidural analgesia for labor.

STUDY OBJECTIVE: This systematic review aimed to summarize the evidence derived from randomized controlled trials (RCTs) comparing dural puncture epidural analgesia (DPEA) and conventional lumbar epidural analgesia (LEA) for women undergoing labor. INTERVENTIONS: The MEDLINE and EMBASE databases were searched from inception to July 2018 in order to find RCTs published in the English language, which investigated DPEA in laboring women. MAIN RESULTS: Six RCTs were included in the final analysis. Their collective results remain ambiguous. Dural puncture with small (i.e., 26- or 27-gauge) spinal needles seems to confer either minimal benefits or improved analgesic quality and lower pain scores in the first 10 min. Dural puncture with 25-gauge spinal needles has been reported to provide higher success rate than conventional LEA in one trial; however two other studies could only agree on the fact that DPEA results in improved sacral blockade and fewer unilateral blocks compared to LEA. CONCLUSIONS: The current evidence regarding DPEA for labor analgesia remains ambiguous. Future research should investigate the optimal (spinal) needle size for dural puncture as well as factors governing transmeningeal flux of local anesthetics and opioids in the presence of a dural hole.

Diaphragm-sparing nerve blocks for shoulder surgery, revisited.

Although interscalene brachial plexus block (ISB) remains the gold standard for analgesia after shoulder surgery, the inherent risks of ipsilateral phrenic nerve block and hemidiaphragmatic paralysis (HDP) limit its use in patients with preexisting pulmonary compromise. In a previous Daring Discourse (2017), our research team has identified potential diaphragm-sparing alternatives to ISB for patients undergoing shoulder surgery. In recent years, the field has been fertile with research, with the publication of multiple randomized controlled trials investigating supraclavicular blocks, upper trunk blocks, anterior suprascapular nerve blocks, costoclavicular blocks, and combined infraclavicular-suprascapular blocks. To date, the cumulative evidence (pre-2017 and post-2017) suggests that costoclavicular blocks may provide similar postoperative analgesia to ISB coupled with a 0%-incidence of HDP. However, in light of the small number of patients recruited by the single study investigating costoclavicular blocks, further confirmatory trials are required. Moreover, future investigation should also be undertaken to determine if costoclavicular blocks could achieve surgical anesthesia for shoulder surgery. Anterior suprascapular nerve blocks have been demonstrated to provide surgical anesthesia and similar analgesia to ISB. However, their risk of HDP has not been formally quantified. Of the remaining diaphragm-sparing nerve blocks, supraclavicular blocks (with local anesthetic injection posterolateral to the brachial plexus), upper trunk blocks, and combined infraclavicular-anterior suprascapular blocks merit further investigation, as they have been shown to achieve similar analgesia to ISB, coupled with an HDP incidence <10%.

Randomized comparison between interscalene and costoclavicular blocks for arthroscopic shoulder surgery.

BACKGROUND: This randomized trial compared ultrasound-guided interscalene block (ISB) and costoclavicular brachial plexus block (CCB) for arthroscopic shoulder surgery. We hypothesized that CCB would provide equivalent analgesia to ISB 30 min after surgery without the risk of hemidiaphragmatic paralysis. METHODS: All 44 patients received an ultrasound-guided block of the intermediate cervical plexus. Subsequently, they were randomized to ISB or CCB. The local anesthetic agent (20 mL of levobupivacaine 0.5% and epinephrine 5 µg/mL) and pharmacological block adjunct (4 mg of intravenous dexamethasone) were identical for all study participants. After the block performance, a blinded investigator assessed ISBs and CCBs every 5 min until 30 min using a composite scale that encompassed the sensory function of the supraclavicular nerves, the sensorimotor function of the axillary nerve and the motor function of the suprascapular nerve. A complete block was defined as one displaying a minimal score of six points (out of a maximum of eight points) at 30 min. Onset time was defined as the time required to reach the six-point minimal composite score. The blinded investigator also assessed the presence of hemidiaphragmatic paralysis at 30 min with ultrasonography.Subsequently, all patients underwent general anesthesia. Postoperatively, a blinded investigator recorded pain scores at rest at 0.5, 1, 2, 3, 6, 12, and 24 hours. Patient satisfaction at 24 hours, consumption of intraoperative and postoperative narcotics, and opioid-related side effects (eg, nausea/vomiting, pruritus) were also tabulated. RESULTS: Both groups displayed equivalent postoperative pain scores at 0.5, 1, 2, 3, 6, 12, and 24 hours. ISB resulted in a higher incidence of hemidiaphragmatic paralysis (100% vs 0%; P < 0.001) as well as a shorter onset time (14.0 (5.0) vs 21.6 (6.4) minutes; p<0.001). However, no intergroup differences were found in terms of proportion of patients with minimal composite scores of 6 points at 30 min, intraoperative/postoperative opioid consumption, side effects, and patient satisfaction at 24 hours. CONCLUSION: Compared to ISB, CCB results in equivalent postoperative analgesia while circumventing the risk of hemidiaphragmatic paralysis. Further confirmatory trials are required. Future studies should also investigate if CCB can provide surgical anesthesia for arthroscopic shoulder surgery. CLINICAL TRIALS REGISTRATION: NCT03411343.

Randomized comparison between perineural dexamethasone and dexmedetomidine for ultrasound-guided infraclavicular block.

BACKGROUND: This randomized trial compared perineural dexamethasone (5 mg) and dexmedetomidine (100 µg) for ultrasound-guided infraclavicular brachial plexus block. We hypothesized that both adjuvants would result in similar durations of motor block and therefore designed the study as an equivalence trial (equivalence margin=3.0 hours). METHODS: One hundred and twenty patients undergoing upper limb surgery with ultrasound-guided infraclavicular block (using 35 mL of lidocaine 1%-bupivacaine 0.25% with epinephrine 5 µg/mL) were randomly allocated to receive perineural dexamethasone (5 mg) or dexmedetomidine (100 µg). Patients and operators were blinded to the nature of the perineural adjuvant. After the performance of the block, a blinded observer assessed the success rate (defined as a minimal sensorimotor composite score of 14 out of 16 points at 30 min) as well as the incidence of surgical anesthesia (defined as the ability to complete surgery without local infiltration, supplemental blocks, intravenous opioids, or general anesthesia). Heart rate and blood pressure were recorded before the block as well as during the first 2 hours after its performance. Furthermore, the level of sedation (using the Ramsay Sedation Scale) was recorded in the postanesthesia care unit. Postoperatively, the blinded observer contacted patients with successful blocks to inquire about the duration of motor block, sensory block, and postoperative analgesia. RESULTS: No intergroup differences were observed in terms of success rate and surgical anesthesia. Compared with dexmedetomidine, dexamethasone provided longer durations of motor block (17.4 (4.0) vs 14.3 (3.0) hours; p<0.001; 95% CI 1.7 to 4.5), sensory block (19.0 (4.0) vs 15.0 (3.2) hours; p<0.001; 95% CI 2.6 to 5.4), and analgesia (22.2 (3.6) vs 16.9 (3.9) hours; p<0.001; 95% CI 3.7 to 6.9). Dexmedetomidine resulted in lower heart rate and blood pressure after the performance of the block, as well as an increased level of sedation postoperatively. CONCLUSION: Compared with dexmedetomidine (100 µg), dexamethasone (5 mg) results in longer sensorimotor block and analgesic durations, as well as a decreased level of patient sedation. Further studies are required to compare dexamethasone and dexmedetomidine using different doses, local anesthetic agents, and approaches to the brachial plexus. TRIAL REGISTRATION NUMBER: NCT03610893.

Randomized comparison between epidural waveform analysis through the needle versus the catheter for thoracic epidural blocks.

BACKGROUND: Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for loss of resistance (LOR): when the needle/catheter tip is correctly positioned inside the epidural space, pressure measurement results in a pulsatile waveform. Epidural waveform analysis can be carried out through the tip of the needle (EWA-N) or the catheter (EWA-C). In this randomized trial, we compared the two methods. We hypothesized that, compared with EWA-C, EWA-N would result in a shorter performance time. METHODS: One hundred and twenty patients undergoing thoracic epidural blocks for thoracic or abdominal surgery were randomized to EWA-N or EWA-C. In the EWA-N group, LOR was confirmed by connecting the epidural needle to a pressure transducer. After obtaining a satisfactory waveform, the epidural catheter was advanced 5 cm beyond the needle tip. In the EWA-C group, the epidural catheter was first advanced 5 cm beyond the needle tip after the occurrence of LOR. Subsequently, the catheter was connected to the pressure transducer to detect the presence of waveforms. In both study groups, the block procedure was repeated at different intervertebral levels until positive waveforms could be obtained (through the needle or catheter as per the allocation) or until a predefined maximum of three intervertebral levels had been reached. Subsequently, the operator administered a 4 mL test dose of lidocaine 2% with epinephrine 5 µg/mL through the catheter. An investigator present during the performance of the block recorded the performance time (defined as the temporal interval between skin infiltration and local anesthetic administration through the epidural catheter). Fifteen minutes after the test dose, a blinded investigator assessed the patient for sensory block to ice. Success was defined as a bilateral block in at least two dermatomes. Furthermore, postoperative pain scores, local anesthetic consumption, and breakthrough analgesic consumption were recorded. RESULTS: No intergroup differences were found in terms of performance time, success rate, postoperative pain, local anesthetic requirement, and breakthrough analgesic consumption. CONCLUSION: EWA can be carried out through the needle or through the catheter with similar efficiency (performance time) and efficacy (success rate, postoperative analgesia). TRIAL REGISTRATION NUMBER: NCT03603574.

Dural puncture epidural analgesia for labor: a randomized comparison between 25-gauge and 27-gauge pencil point spinal needles.

BACKGROUND: This double-blind, randomized trial compared dural puncture epidural analgesia (DPEA) for labor using 25-gauge and 27-gauge pencil point spinal needles. We hypothesized that both needle sizes would result in similar onset time (equivalence margin=2.5 min) and therefore designed the study as an equivalence trial. METHODS: One hundred and forty patients undergoing labor were randomized to DPEA with 25-gauge (n=70) or 27-gauge (n=70) pencil point spinal needles. After the placement of the epidural catheter, a bolus of 20 mL of bupivacaine 0.125% and fentanyl 2 µg/mL was administered to all subjects. Thereafter, patients received boluses of 12 mL of bupivacaine 0.125% every 2 hours as needed.A blinded investigator recorded the onset time (defined as the temporal interval required to achieve a pain score ≤1 on a 0-10 scale), S2 block, sensory block height (30 min after the initial bolus of local anesthetic), presence of motor block (30 min after the initial bolus of local anesthetic), number of top-up doses required during labor and incidence of postural headache. RESULTS: Out of the 140 recruited patients, 135 were retained for analysis. Compared with their 27-gauge counterparts, 25-gauge pencil point spinal needles provided a 1.6 min shorter DPEA onset (95% CI of the difference of the means: -3.2 to -0.1 min). However, there were no intergroup differences in terms of S2 block, sensory block height, motor block, number of top-up doses and incidence of postural headache. CONCLUSION: Dural puncture epidural analgesia with 25-gauge pencil point spinal needles provides a 1.6 min shorter onset time than DPEA with 27-gauge spinal needles. Although statistically significant, such a difference may not be clinically relevant. Further investigation is required to compare 25-gauge and 27-gauge spinal needles for DPEA in the setting of different local anesthetic infusion strategies. TRIAL REGISTRATION NUMBER: NCT03389945.

A multicenter, randomized comparison between 2, 5, and 8 mg of perineural dexamethasone for ultrasound-guided infraclavicular block.

BACKGROUND AND OBJECTIVES: This multicenter, randomized trial compared 2, 5, and 8 mg of perineural dexamethasone for ultrasound-guided infraclavicular brachial plexus block. Our research hypothesis was that all three doses of dexamethasone would result in equivalent durations of motor block (equivalence margin=3.0 hours). METHODS: Three hundred and sixty patients undergoing upper limb surgery with ultrasound-guided infraclavicular block were randomly allocated to receive 2, 5, or 8 mg of preservative-free perineural dexamethasone. The local anesthetic agent (35 mL of lidocaine 1%-bupivacaine 0.25% with epinephrine 5 µg/mL) was identical in all subjects. Patients and operators were blinded to the dose of dexamethasone. During the performance of the block, the performance time, number of needle passes, procedural pain, and complications (vascular puncture, paresthesia) were recorded. Subsequently a blinded observer assessed the success rate (defined as a minimal sensorimotor composite score of 14 out of 16 points at 30 min), onset time as well as the incidence of surgical anesthesia (defined as the ability to complete surgery without local infiltration, supplemental blocks, intravenous opioids, or general anesthesia). Postoperatively, the blinded observer contacted patients with successful blocks to inquire about the duration of motor block, sensory block, and postoperative analgesia. The main outcome variable was the duration of motor block. RESULTS: No intergroup differences were observed in terms of technical execution (performance time/number of needle passes/procedural pain complications), onset time, success rate, and surgical anesthesia. Furthermore, all three doses of dexamethasone provided similar durations of motor block (14.9-16.1 hours) and sensory block. Although 5 mg provided a longer analgesic duration than 2 mg, the difference (2.7 hours) fell within our pre-established equivalence margin (3.0 hours). CONCLUSIONS: 2, 5, and 8 mg of dexamethasone provide clinically equivalent sensorimotor and analgesic durations for ultrasound-guided infraclavicular block. Further trials are required to compare low (ie, 2 mg) and ultra-low (eg, 0.5-1 mg) doses of perineural dexamethasone for brachial plexus blocks. TRIAL REGISTRATION NUMBER: TCTR20150624001.

A Randomized Comparison Between Interscalene and Small-Volume Supraclavicular Blocks for Arthroscopic Shoulder Surgery.

BACKGROUND AND OBJECTIVES: This randomized trial compared ultrasound (US)-guided interscalene block (ISB) and small-volume supraclavicular block (SCB) for arthroscopic shoulder surgery. We hypothesized that SCB would provide equivalent analgesia to ISB 30 minutes after surgery without the risk of hemidiaphragmatic paralysis (HDP). METHODS: All patients received an US-guided intermediate cervical plexus block. In the ISB group, US-guided ISB was performed with 20 mL of levobupivacaine 0.5% and epinephrine 5 µg/mL. In the SCB group, US-guided SCB was carried out using 20 mL of the same local anesthetic agent: 3 and 17 mL were deposited at the "corner pocket" (ie, intersection of the first rib and subclavian artery) and posterolateral to the brachial plexus, respectively. A blinded investigator assessed ISBs and SCBs every 5 minutes until 30 minutes using a composite scale that encompassed the sensory function of the supraclavicular nerves, the sensorimotor function of the axillary nerve, and the motor function of the suprascapular nerve. We considered the blocks complete if, at 30 minutes, a composite score equal or superior to 6 points (out of 8 points) was achieved. Thus, onset time was defined as the time required to reach a minimal composite score of 6 points. The blinded investigator also assessed the presence of HDP at 30 minutes with US. Subsequently, all patients underwent general anesthesia. Postoperatively, a blinded investigator recorded pain scores at rest at 0.5, 1, 2, 3, 6, 12, and 24 hours. Patient satisfaction at 24 hours, consumption of intraoperative and postoperative narcotics, and opioid-related adverse effects were also tabulated. RESULTS: Both groups displayed equivalent postoperative pain scores at 0.5, 1, 2, 3, 6, 12, and 24 hours. Interscalene blocks resulted in a higher incidence of HDP (95% vs 9%; P < 0.001), a shorter onset time, and a higher proportion of patients with minimal composite scores of 6 points at 30 minutes (100% vs 77%; P = 0.048). However, no intergroup differences were found in terms of performance time, procedural pain, number of needle passes, intraoperative/postoperative opioid consumption, adverse effects, and patient satisfaction at 24 hours. CONCLUSIONS: Compared with ISB, small-volume SCB results in equivalent postoperative analgesia and a lower incidence of HDP. Because the latter cannot be completely avoided with small-volume SCB, further trials are required to investigate the optimal diaphragm-sparing nerve block for shoulder surgery. CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov, identifier NCT03224884.