Regional Anesthesia and Pain Medicine最新文献

Background: Intrathecal morphine is the standard for post-cesarean analgesia but often causes pruritus and may be unavailable in resource-limited settings. This study assessed whether a combination of bilateral transversus abdominis plane (TAP) block and intrathecal fentanyl provides non-inferior analgesia compared with intrathecal morphine following cesarean delivery within the multimodal analgesia context.

Methods: Eighty mothers were randomized to receive either intrathecal fentanyl 10 µg with bilateral TAP block using 15 mL of 0.375% ropivacaine per side (TF group) or intrathecal morphine 75 µg with a saline sham block (M group). All patients received standard multimodal analgesia. Primary outcome was pain score with movement at 24 hours postoperatively, with a non-inferiority margin of 1 on the numeric rating scale. Secondary outcomes included opioid consumption, time to first opioid, pruritus, nausea/vomiting, patient satisfaction, and neonatal outcomes.

Results: The mean pain score with movement at 24 hours was 5.4 in the TF group and 4.8 in the M group (mean difference (95% CI), 0.6 (-0.3 to 1.5), p=0.202), with the upper margin of 95% CI exceeding the non-inferior margin. Postoperative fentanyl consumption was higher in the TF group (median (IQR), 585 (390-745) vs 140 (55-405) µg; p<0.001). Pruritus was more frequent in the M group (60% vs 10%; p<0.001).

Conclusions: Bilateral TAP block with intrathecal fentanyl is not non-inferior to intrathecal morphine for post-cesarean analgesia. However, intrathecal morphine was associated with a higher incidence of pruritus, suggesting TAP block with intrathecal fentanyl as a suitable alternative when reducing pruritus is a priority.

Trial registration number: NCT04824274.

Background: Sacroiliac joint (SIJ) dysfunction accounts for the etiology of pain in 15%-30% of low back pain cases. Some patients with conservative treatment-refractory SIJ dysfunction undergo radiofrequency (RF) ablation of the SIJ for prolonged pain relief. This procedure involves placing up to 12 RF probes in what is an invasive, resource-intensive, and time-consuming process. High-intensity focused ultrasound is an alternative neuroablative technique that is non-invasive and potentially less cumbersome. MRI-guided high-intensity focused ultrasound (MRgHIFU) had previously been successfully applied to SIJ ablation in a swine model, and more recently had been trialed in humans. However, ultrasound-guided high-intensity focused ultrasound (USgHIFU) of the SIJ may be a more practical and rapid alternative to MRIgHIFU.

Methods: This was a prospective technology efficacy and safety study in a swine model. Three Yorkshire pigs underwent bilateral SIJ ablation using a proprietary USgHIFU prototype. Post procedure, treatment efficacy was assessed using clinical evaluation of pain and changes in ambulation, gross inspection of lumbosacral necropsy and pathology sections, and histology.

Results: Post anesthetic monitoring for 72 hours showed no signs of gait abnormalities or perceived pain in the swine models. Of the primary sacral spine targets, histological specimen review suggested successful lesioning of 37/54 sites (68.5%), specifically in the targeted areas that were visualized under ultrasound. Of the successful lesion zones, 22/37 (59.5%) included nerve lesions, 34/37 (91.9%) included muscle lesions, 34/37 (91.9%) included periosteum lesions, and 20/21 (95.2%) included bony lesions.

Conclusions: The preliminary study thus demonstrates that USgHIFU can create targeted contiguous strip lesions along the SIJ and lead to thermal necrosis of the posterior sacral network without causing additional neurological damage or damage to adjacent muscle tissue or bone outside of target areas.

Background: This study evaluated the effectiveness of large language models (LLMs), specifically ChatGPT 4o and a custom-designed model, Meta-Analysis Librarian, in generating accurate search strings for systematic reviews (SRs) in the field of anesthesiology.

Methods: We selected 85 SRs from the top 10 anesthesiology journals, according to Web of Science rankings, and extracted reference lists as benchmarks. Using study titles as input, we generated four search strings per SR: three with ChatGPT 4o using general prompts and one with the Meta-Analysis Librarian model, which follows a structured, Population, Intervention, Comparator, Outcome-based approach aligned with Cochrane Handbook standards. Each search string was used to query PubMed, and the retrieved results were compared with the PubMed retrieved studies from the original search string in each SR to assess retrieval accuracy. Statistical analysis compared the performance of each model.

Results: Original search strings demonstrated superior performance with a 65% (IQR: 43%-81%) retrieval rate, which was statistically different from both LLM groups in PubMed retrieved studies (p=0.001). The Meta-Analysis Librarian achieved a superior median retrieval rate to ChatGPT 4o (median, (IQR); 24% (13%-38%) vs 6% (0%-14%), respectively).

Conclusion: The findings of this study highlight the significant advantage of using original search strings over LLM-generated search strings in PubMed retrieval studies. The Meta-Analysis Librarian demonstrated notable superiority in retrieval performance compared with ChatGPT 4o. Further research is needed to assess the broader applicability of LLM-generated search strings, especially across multiple databases.

Introduction: During peripheral nerve blocks, inadvertent intraneural injection is not infrequent. Recently, with sonographic nerve swelling, it has been shown that intraneural injection can be detected as early as 0.4 mL. A new method based on injection pressure monitoring at the needle tip, the real pressure in the tissues, is compared with sonographic performance in early detection of intraneural injection.

Methods: This cadaver study was conducted on the upper limb of fresh cadavers. Senior anesthesiologists performed ultrasound guided intraneural injections of the nerves using a modified Visioplex needle with a fiberoptic sensor embedded. 12 injections were performed, two on each nerve (radial, ulnar, and median) for each anatomical preparation. 3 mL of saline methylene blue mix was injected at 10 mL/min. Recordings of ultrasound screen and pressure curves were blindly analyzed to evaluate nerve swelling and injection pressures.

Results: An immediate increase in injection pressure from time zero was observed in all 12 intraneural injections, with similar trends. After only 0.2 mL, intraneural injection was clearly identified as the pressure curves had already risen to an average of 120 mm Hg (SD 5). Nerve swelling was observed in 10 of 12 injections (83%). This was evident after an average of 1.2 mL (SD 0.5). Following injections, dissection of specimens confirmed intraneural spread in all cases.

Conclusion: Pressure monitoring at the needle tip consistently showed a pressure rise from the onset of injection and proved to be a more sensitive and earlier indicator of intraneural injection than sonographic nerve swelling.

Introduction: Postherpetic neuralgia (PHN) is a common complication of herpes zoster (HZ). This study aimed to use a large real-world electronic medical records database to determine the optimal machine learning model for predicting the progression to severe PHN and to identify the associated risk factors.

Methods: We analyzed the electronic medical records of 23,326 patients diagnosed with HZ from January 2010 to June 2020. PHN was defined as pain persisting for ≥90 days post-HZ, based on diagnostic and prescription codes. Five machine learning algorithms were compared with select the optimal predictive model and a subsequent risk factor analysis was conducted.

Results: Of the 23,326 patients reviewed, 8,878 met the eligibility criteria for the HZ cohort. Among these, 801 patients (9.0%) progressed to severe PHN. Among the various machine learning approaches, XGBoost-an approach that combines multiple decision trees to improve predictive accuracy-performed the best in predicting outcomes (F1 score, 0.351; accuracy, 0.900; area under the receiver operating characteristic curve, 0.787). Using this model, we revealed eight major risk factors: older age, female sex, history of shingles and cancer, use of immunosuppressants and antidepressants, intensive initial pain, and the neutrophil-to-lymphocyte ratio. When patients were categorized into low-risk and high-risk groups based on the predictive model, PHN was seven times more likely to occur in the high-risk group (p<0.001).

Conclusions: Leveraging machine learning analysis, this study identifies an optimal model for predicting severe PHN and highlights key associated risk factors. This model will enable the establishment of more proactive treatments for high-risk patients, potentially mitigating the progression to severe PHN.

Background/importance: Local anesthetic (LA) mixtures are used in peripheral nerve blocks (PNB) to improve onset, though study results remain conflicting.

Objective: This systematic review and meta-analysis compared the efficacy outcomes of long-acting LA to their mixture with shorter-acting LA in ultrasound-guided PNB. The primary outcome was sensory block onset.

Evidence review: We searched WoS, Scopus, MEDLINE, EMBASE, BVS/LILACS, and Cochrane databases from 1998 to 2024 for randomized controlled trials (RCTs). We conducted a random-effects meta-analysis, evaluated the risk of bias (RoB) with RoB 2.0, performed sensitivity analyses, assessed non-reporting bias with DOI plots and Luis Furuya-Kanamori index, and evaluated strength of evidence with Grading of Recommendations Assessment, Development and Evaluations.

Findings: We included 10 RCTs (516 participants). Mixture of LA may have no effect on sensory block onset (mean difference (MD) -1.62 min, 95% CI: -4.04 to 0.81; I²=81.50%, 95% CI: 62.82% to 90.80%; prediction interval (PI)=-7.78 to 4.55; very low certainty) and motor block onset (MD -5.60 min; 95% CI: -14.54 to 3.33, I²=98.89%, 95% CI: 98.50% to 99.18%; PI=-31.90 to 20.69; very low certainty), while it may reduce the duration of sensory block (MD -2.16 hours, 95% CI: -4.16 to -0.17; I²=90.77%, 95% CI: 84.22% to 94.60%; PI=-7.24 to 2.92; very low certainty).

Conclusions: LA mixtures may not affect sensory and motor block onset in ultrasound-guided PNB but could shorten the duration of sensory blockade.

This paper explores the rapid emergence of xylazine exposure in the USA and its implications for anesthesiologists. Xylazine, a non-opioid sedative and analgesic often used in veterinary medicine, has increasingly been found as an adulterant in the illicit substance supply, leading to serious health implications. The pharmacological properties of xylazine, its clinical effects, and the challenges it poses for clinicans will be discussed. Perioperative strategies for anesthesiologists to manage these potential cases are provided. Furthermore, this paper necessitates an epidemiological understanding for detection and multidisciplinary collaboration in addressing this emerging public health threat. The manuscript concludes by emphasizing the role anesthesiologists will have to play in managing the clinical implications of xylazine and contributing to public health strategies aimed at curbing its misuse.