The nociceptive withdrawal reflex (NWR) is a protective limb withdrawal response triggered by painful stimuli, used to assess spinal nociceptive excitability. Conventionally, the NWR is understood as having two reflex responses: a short-latency Aβ-mediated response, considered tactile, and a longer-latency Aδ-mediated response, considered nociceptive. However, nociceptors with conduction velocities similar to Aβ tactile afferents have been identified in human skin. In this study, we investigated the effect of a preferential conduction block of Aβ fibers on pain perception and NWR signaling evoked by intradermal electrical stimulation in healthy participants. We recorded a total of 198 NWR responses in the intact condition, and no dual reflex responses occurred within our latency bandwidth (50-150 ms). The current required to elicit the NWR was higher than the perceptual pain threshold, indicating that NWR did not occur before pain was felt. In the block condition, when the Aβ-mediated tuning fork sensation was lost while Aδ-mediated nonpainful cooling was still detectable (albeit reduced), we observed that the reflex was abolished. Further, short-latency electrical pain intensity at pre-block thresholds was greatly reduced, with any residual pain sensation having a longer latency. Although electrical pain was unaffected at suprathreshold current, the reflex could not be evoked despite a two-fold increase in the pre-block current and a five-fold increase in the pre-block pulse duration. These observations lend support to the possible involvement of Aβ-fiber inputs in pain and reflex signaling.

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OBJECTIVE: This study aimed to assess the feasibility and effectiveness of the pectoral nerves (PECS) II block in facilitating cardiac implantable electronic device (CIED) insertion in a sample of 120 patients, with a focus on the percentage of cases completed without additional intraoperative local anesthesia.
METHODS: PECS II blocks were performed on the left side using ultrasound guidance in all 120 patients. Feasibility was assessed by the proportion of cases completed without the need for extra intraoperative local anesthetic. Secondary outcomes included the amount of additional local anesthetic used, intraoperative opioid requirements, postoperative pain scores, time to first postoperative analgesia, analgesic consumption, patient satisfaction, and block-related complications.
RESULTS: Of the 120 patients, 78 (65%) required additional intraoperative local anesthetic, with a median volume of 8.2 mL (range 3-13 mL). Fifteen patients (12.5%) needed intraoperative opioid supplementation. Nine patients (7.5%) required postoperative tramadol for pain relief. In total, 98 patients (81.7%) reported high satisfaction levels with the procedure.
CONCLUSIONS: The PECS II block, when combined with supplementary local anesthetic, provided effective postoperative analgesia for at least 24 h in 120 patients undergoing CIED insertion. While it did not completely replace surgical anesthesia in most cases, the PECS II block significantly contributed to a smoother intraoperative experience for patients.

The procedure with the highest rate of opioid prescription in plastic surgery is abdominoplasty. Additionally, plastic surgery patients are at a particularly elevated risk of becoming opioid-dependent. The main objective of this study was to perform a systematic review and create an algorithm for a multimodal pain regimen specific to patients undergoing abdominoplasty. A systematic search of the research literature was performed to summarize the prevailing understanding of multimodal pain control in the management of abdominoplasty. The initial search yielded 448 articles. Sixty-eight manuscripts were identified for full-text review. The effectiveness of current strategies was evaluated by way of pain scores, opioid usage, and length of stay, as well as other measures of physical function such as time to early mobilization. In 32 studies involving 2451 patients, the efficacy of different pain regimens during abdominoplasty was evaluated. Among nontraditional, opioid-sparing analgesia, efficacy of treatment interventions for improved pain and decreased opioid usage was found inall studies. Among local infusion studies, efficacy of treatment interventions for improved pain and decreased opioid usage was found in 78% of studies. Last, among regional block studies, efficacy of treatment interventions for improved pain was found in 87%, with 73% efficacy for decreased opioid usage. Multimodal pain regimens in abdominoplasty have the potential to play an important role in opioid-sparing practices in medicine by incorporating nonopioid pain adjuvants such as nonsteroidal anti-inflammatory drugs and transversus abdominis plane blocks in the preoperative, perioperative, and postoperative periods.
METHODS:

BACKGROUND: Enhanced recovery after surgery (ERAS) pathways have been widely shown to yield positive outcomes, including in plastic surgery. Our group has previously validated ERAS in our deep inferior epigastric perforator flap breast reconstruction population.
OBJECTIVE: We evaluated whether the ERAS protocol and addition of liposomal bupivacaine affected patient outcomes at the time of mastectomy and first-stage tissue expander reconstruction.
METHODS: All patients treated between July 2021 and May 2022 were reviewed retrospectively. The ERAS protocol was implemented in December 2021. Two patient groups were compared: pre-ERAS and ERAS. The ERAS protocol included use of liposomal bupivacaine in the pectoralis nerve block 1/2 planes. Primary outcomes were observed with postoperative length of stay and hospital narcotic use.
RESULTS: Eighty-one patients were analyzed in this cohort. The pre-ERAS group was composed of 41 patients, the ERAS group was composed of 83 patients. Postoperative length of stay was significantly reduced in the ERAS group (1.7 pre-ERAS vs 1.1 ERAS, P = .0004). When looking at morphine equivalents during the hospital stay, the degree of narcotics in the recovery room was relatively similar. Average PACU pain morphine equivalents were 6.1 pre-ERAS vs 7.1 ERAS (P = .406). However, total hospital morphine equivalents were significantly lower in the ERAS group (65.0 pre-ERAS vs 26.2 ERAS, P = <.001).
CONCLUSIONS: The introduction of an enhanced recovery after surgery protocol with liposomal bupivacaine pectoralis 1/2 nerve blocks decreased postoperative opioid consumption and hospital length of stay in mastectomy patients undergoing tissue expander-based reconstruction.
METHODS:

暂无摘要。

BACKGROUND: Acute post-subarachnoid hemorrhage (SAH) headaches are common and severe. Management strategies for post-SAH headaches are limited, with heavy reliance on opioids, and pain control is overall poor. Pterygopalatine fossa (PPF) nerve blocks have shown promising results in treatment of acute headache, including our preliminary and published experience with PPF-blocks for refractory post-SAH headache during hospitalization. The BLOCK-SAH trial was designed to assess the efficacy and safety of bilateral PPF-blocks in awake patients with severe headaches from aneurysmal SAH who require opioids for pain control and are able to verbalize pain scores.
METHODS: BLOCK-SAH is a phase II, multicenter, randomized, double-blinded, placebo-controlled clinical trial using the sequential parallel comparison design (SPCD), followed by an open-label phase.
RESULTS: Across 12 sites in the United States, 195 eligible study participants will be randomized into three groups to receive bilateral active or placebo PPF-injections for 2 consecutive days with periprocedural monitoring of intracranial arterial mean flow velocities with transcranial Doppler, according to SPCD (group 1: active block followed by placebo; group 2: placebo followed by active block; group 3: placebo followed by placebo). PPF-injections will be delivered under ultrasound guidance and will comprise 5-mL injectates of 20 mg of ropivacaine plus 4 mg of dexamethasone (active PPF-block) or saline solution (placebo PPF-injection).
CONCLUSIONS: The trial has a primary efficacy end point (oral morphine equivalent/day use within 24 h after each PPF-injection), a primary safety end point (incidence of radiographic vasospasm at 48 h from first PPF-injection), and a primary tolerability end point (rate of acceptance of second PPF-injection following the first PPF-injection). BLOCK-SAH will inform the design of a phase III trial to establish the efficacy of PPF-block, accounting for different headache phenotypes.

OBJECTIVE: In this study, we evaluated the efficacy and safety of 1 μg/kg dexmedetomidine as an adjuvant treatment to ropivacaine in children undergoing upper limb surgeries under ultrasound-guided axillary brachial plexus blocks and general anesthesia.
METHODS: We enrolled 90 children (aged 1-8 years; ASA I-II) undergoing closed reduction and internal fixation for upper extremity fractures at the Xiamen Children\'s Hospital and randomly assigned them to one of two groups: L (injection with 0.25% ropivacaine) or D (injection with 0.25% ropivacaine containing 1 μg/kg dexmedetomidine) using the random number table method. The main outcome indicators recorded were the facial expression, leg activity, position, crying, and Face, Legs, Activity, Cry, and Consolability (FLACC) scale scores of children after surgery and the duration of block and analgesia maintenance. The secondary outcome indicators were vital sign data at the time of ultrasound probe placement (T1), at the time of block completion (T2), prior to the beginning of surgery (T3), 5 min after the beginning of surgery (T4), and at the end of surgery (T5), as well as the time of postoperative recovery, the number of cases of remedial analgesia, and complications.
RESULTS: There was no statistical difference between the two groups in terms of general data, block completion time, postoperative recovery time, and complications (P > 0.05). Compared to the L group, the D group had significantly lower FLACC scores at 6 h after surgery, as well as significantly lower systolic blood pressure, diastolic blood pressure, and heart rate values at T4 and T5, and significantly longer duration of postoperative analgesia maintenance (all P < 0.05).
CONCLUSIONS: Dexmedetomidine (1 μg/kg) as a local anesthetic adjuvant to ropivacaine can alleviate pain at 6 h postoperatively, prolong analgesia maintenance, and reduce intraoperative blood pressure and heart rate in pediatric patients undergoing closed reduction and internal fixation for upper extremity fractures, with no obvious complications or delayed recovery.
UNASSIGNED: Registration website: www.chictr.org.cn, Registration number: ChiCTR2200065163, Registration date: October, 30, 2022.

BACKGROUND: Ultrasound-guided supraclavicular block (UGSCB) is an emerging technique gaining interest amongst emergency physicians that provides regional anaesthesia to the upper limb to tolerate painful procedures. It offers an alternative to the more traditional technique of a Bier block (BB). However, the effectiveness or safety of UGSCB when performed in the emergency department (ED) is unclear.
METHODS: SUPERB (SUPraclavicular block for Emergency Reduction versus Bier block) is a prospective open-label non-inferiority randomised controlled trial comparing the effectiveness of UGSCB versus BB for closed reduction of upper limb fractures and/or dislocations. Adult patients presenting with upper limb fracture and/or dislocation requiring closed reduction in ED were randomised to either UGSCB or BB. Once regional anaesthesia is obtained, closed reduction of the injured part was performed and immobilised. The primary outcome is maximal pain experienced during closed reduction measured via a visual analogue scale (VAS). Secondary outcomes include post-reduction pain, patient satisfaction, total opioid requirement in ED, ED length of stay, adverse events and regional anaesthesia failure.
RESULTS: Primary outcome analysis will be performed using both the intention-to-treat and per-protocol populations. The between-group difference in maximum pain intensity will be assessed using linear regression modelling with trial group allocation (UGSCB vs BB) included as a main affect. A pre-specified non-inferiority margin of 20 mm on the VAS scale will be used to establish non-inferiority of UGSCB compared to BB.
CONCLUSIONS: SUPERB is the first randomised controlled trial to investigate the effectiveness and safety of UGSCB in the ED. The trial has the potential to demonstrate that UGSCB is an alternative safe and effective option for the management of upper extremity emergencies in the ED.

OBJECTIVE: Ultrasound-guided erector spinae plane block (ESPB) is commonly used for perioperative analgesia in adults; however, its analgesic efficacy and safety in pediatric patients remain uncertain. This review aimed to determine whether ultrasound-guided ESPB can improve analgesic efficacy and safety in pediatric surgery.
METHODS: Meta-analysis of randomized controlled trials.
METHODS: Perioperative setting.
METHODS: Pediatric patients undergoing elective surgery under general anesthesia.
METHODS: We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, KoreaMed, Web of Science, Scopus, and ClinicalTrials.gov databases for eligible published randomized controlled studies (RCTs) comparing ESPB with controls (no block or other block) in pediatric patients undergoing elective surgery under general anesthesia.
METHODS: The primary outcome was cumulative opioid consumption after surgery. Other outcomes included intraoperative opioid consumption, time to first request for rescue analgesia, number of patients requiring rescue analgesics, and pain scores after surgery. The safety outcomes were the incidences of bradycardia, hypotension, and postoperative vomiting.
RESULTS: The analysis included 17 RCTs comprising 919 participants: 461 in the ESPB group, 269 in the no-block group (no block/sham block), and 189 in the other block group. Compared with the control group (no block and other blocks), ESPB significantly reduced the cumulative opioid consumption (intravenous morphine milligram equivalents) after surgery (standardized mean difference = -1.51; 95% confidence interval, -2.39 to -0.64; P = 0.0002; I2 = 92.9%) and intraoperative opioid consumption, and lowered average pain scores up to 24 h after surgery. ESPB extended the time to the first request for rescue analgesia and decreased the number of patients requiring rescue analgesics. Furthermore, ESPB lowered the pain score at most time points for 24 h after surgery, improved parental satisfaction, and reduced the incidence of postoperative vomiting compared with that in no block/sham block.
CONCLUSIONS: ESPB provides effective and safe perioperative analgesia in pediatric patients undergoing elective surgery under general anesthesia.