Effectiveness of preoxygenation strategies: a systematic review and network meta-analysis.

BACKGROUND: Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia. METHODS: We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations. RESULTS: We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position. CONCLUSIONS: Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42022326046.

Artificial intelligence for ultrasound scanning in regional anaesthesia: a scoping review of the evidence from multiple disciplines.

BACKGROUND: Artificial intelligence (AI) for ultrasound scanning in regional anaesthesia is a rapidly developing interdisciplinary field. There is a risk that work could be undertaken in parallel by different elements of the community but with a lack of knowledge transfer between disciplines, leading to repetition and diverging methodologies. This scoping review aimed to identify and map the available literature on the accuracy and utility of AI systems for ultrasound scanning in regional anaesthesia. METHODS: A literature search was conducted using Medline, Embase, CINAHL, IEEE Xplore, and ACM Digital Library. Clinical trial registries, a registry of doctoral theses, regulatory authority databases, and websites of learned societies in the field were searched. Online commercial sources were also reviewed. RESULTS: In total, 13,014 sources were identified; 116 were included for full-text review. A marked change in AI techniques was noted in 2016-17, from which point on the predominant technique used was deep learning. Methods of evaluating accuracy are variable, meaning it is impossible to compare the performance of one model with another. Evaluations of utility are more comparable, but predominantly gained from the simulation setting with limited clinical data on efficacy or safety. Study methodology and reporting lack standardisation. CONCLUSIONS: There is a lack of structure to the evaluation of accuracy and utility of AI for ultrasound scanning in regional anaesthesia, which hinders rigorous appraisal and clinical uptake. A framework for consistent evaluation is needed to inform model evaluation, allow comparison between approaches/models, and facilitate appropriate clinical adoption.

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.

Efficacy and safety of intrathecal diamorphine: a systematic review and meta-analysis with meta-regression and trial sequential analysis.

BACKGROUND: Intrathecal diamorphine is believed to provide postoperative analgesia but is associated with adverse effects such as nausea and vomiting. There is little evidence of synthesis regarding intrathecal diamorphine in the contemporary literature. We performed a systematic review, meta-analysis with meta-regression and trial sequential analysis to determine the magnitude of intrathecal diamorphine efficacy and safety. METHODS: We systematically searched the literature for trials comparing intrathecal diamorphine with a control group in patients undergoing all types of surgery. The primary efficacy and safety outcomes were intravenous morphine consumption and incidence of postoperative nausea and vomiting at 24 h following surgery, respectively. RESULTS: Twelve trials were identified, which included data for 712 patients. Intrathecal doses of diamorphine ranged from 100 µg to 2500 µg. Intravenous morphine consumption at 24 h postoperatively was significantly reduced in the intrathecal diamorphine group, with a mean difference (95%CI) of -8 mg (-11 to -6), I2 = 93%, p < 0.001. There was a significant difference between three intrathecal diamorphine dosing subgroups but without correlation: mean differences (95%CI) -1 mg (-3-0), -26 mg (-40 to -11) and -6 mg (-15-4) in patients receiving doses of 0-200 µg, 201-400 µg and > 400 µg, respectively (p = 0.003). Intrathecal diamorphine increased postoperative nausea and vomiting with a risk ratio (95%CI) of 1.37 (1.19-1.58), I2 = 7%, p < 0.001. There were no differences in postoperative nausea and vomiting between the three intrathecal diamorphine dosing subgroups. There was no correlation observed with meta-regression of the primary efficacy and safety outcomes. The quality of evidence for all outcomes was very low. CONCLUSION: There is very low level of evidence that intrathecal diamorphine provides effective analgesia after surgery, while increasing postoperative nausea and vomiting with doses > 200 µg.

Airway management in patients with suspected or confirmed cervical spine injury: Guidelines from the Difficult Airway Society (DAS), Association of Anaesthetists (AoA), British Society of Orthopaedic Anaesthetists (BSOA), Intensive Care Society (ICS), Neuro Anaesthesia and Critical Care Society (NACCS), Faculty of Prehospital Care and Royal College of Emergency Medicine (RCEM).

BACKGROUND: There are concerns that airway management in patients with suspected or confirmed cervical spine injury may exacerbate an existing neurological deficit, cause a new spinal cord injury or be hazardous due to precautions to avoid neurological injury. However, there are no evidence-based guidelines for practicing clinicians to support safe and effective airway management in this setting. METHODS: An expert multidisciplinary, multi-society working party conducted a systematic review of contemporary literature (January 2012-June 2022), followed by a three-round Delphi process to produce guidelines to improve airway management for patients with suspected or confirmed cervical spine injury. RESULTS: We included 67 articles in the systematic review, and successfully agreed 23 recommendations. Evidence supporting recommendations was generally modest, and only one moderate and two strong recommendations were made. Overall, recommendations highlight key principles and techniques for pre-oxygenation and facemask ventilation; supraglottic airway device use; tracheal intubation; adjuncts during tracheal intubation; cricoid force and external laryngeal manipulation; emergency front-of-neck airway access; awake tracheal intubation; and cervical spine immobilisation. We also signpost to recommendations on pre-hospital care, military settings and principles in human factors. CONCLUSIONS: It is hoped that the pragmatic approach to airway management made within these guidelines will improve the safety and efficacy of airway management in adult patients with suspected or confirmed cervical spine injury.

Emergency Airway Management in Patients with COVID-19: A Prospective International Multicenter Cohort Study.

BACKGROUND: Tracheal intubation for patients with COVID-19 is required for invasive mechanical ventilation. The authors sought to describe practice for emergency intubation, estimate success rates and complications, and determine variation in practice and outcomes between high-income and low- and middle-income countries. The authors hypothesized that successful emergency airway management in patients with COVID-19 is associated with geographical and procedural factors. METHODS: The authors performed a prospective observational cohort study between March 23, 2020, and October 24, 2020, which included 4,476 episodes of emergency tracheal intubation performed by 1,722 clinicians from 607 institutions across 32 countries in patients with suspected or confirmed COVID-19 requiring mechanical ventilation. The authors investigated associations between intubation and operator characteristics, and the primary outcome of first-attempt success. RESULTS: Successful first-attempt tracheal intubation was achieved in 4,017/4,476 (89.7%) episodes, while 23 of 4,476 (0.5%) episodes required four or more attempts. Ten emergency surgical airways were reported-an approximate incidence of 1 in 450 (10 of 4,476). Failed intubation (defined as emergency surgical airway, four or more attempts, or a supraglottic airway as the final device) occurred in approximately 1 of 120 episodes (36 of 4,476). Successful first attempt was more likely during rapid sequence induction versus non-rapid sequence induction (adjusted odds ratio, 1.89 [95% CI, 1.49 to 2.39]; P < 0.001), when operators used powered air-purifying respirators versus nonpowered respirators (adjusted odds ratio, 1.60 [95% CI, 1.16 to 2.20]; P = 0.006), and when performed by operators with more COVID-19 intubations recorded (adjusted odds ratio, 1.03 for each additional previous intubation [95% CI, 1.01 to 1.06]; P = 0.015). Intubations performed in low- or middle-income countries were less likely to be successful at first attempt than in high-income countries (adjusted odds ratio, 0.57 [95% CI, 0.41 to 0.79]; P = 0.001). CONCLUSIONS: The authors report rates of failed tracheal intubation and emergency surgical airway in patients with COVID-19 requiring emergency airway management, and identified factors associated with increased success. Risks of tracheal intubation failure and success should be considered when managing COVID-19.

Predicting Hospital Resource Use During COVID-19 Surges: A Simple but Flexible Discretely Integrated Condition Event Simulation of Individual Patient-Hospital Trajectories.

OBJECTIVES: To assist with planning hospital resources, including critical care (CC) beds, for managing patients with COVID-19. METHODS: An individual simulation was implemented in Microsoft Excel using a discretely integrated condition event simulation. Expected daily cases presented to the emergency department were modeled in terms of transitions to and from ward and CC and to discharge or death. The duration of stay in each location was selected from trajectory-specific distributions. Daily ward and CC bed occupancy and the number of discharges according to care needs were forecast for the period of interest. Face validity was ascertained by local experts and, for the case study, by comparing forecasts with actual data. RESULTS: To illustrate the use of the model, a case study was developed for Guy's and St Thomas' Trust. They provided inputs for January 2020 to early April 2020, and local observed case numbers were fit to provide estimates of emergency department arrivals. A peak demand of 467 ward and 135 CC beds was forecast, with diminishing numbers through July. The model tended to predict higher occupancy in Level 1 than what was eventually observed, but the timing of peaks was quite close, especially for CC, where the model predicted at least 120 beds would be occupied from April 9, 2020, to April 17, 2020, compared with April 7, 2020, to April 19, 2020, in reality. The care needs on discharge varied greatly from day to day. CONCLUSIONS: The DICE simulation of hospital trajectories of patients with COVID-19 provides forecasts of resources needed with only a few local inputs. This should help planners understand their expected resource needs.

Airway devices for awake tracheal intubation in adults: a systematic review and network meta-analysis.

BACKGROUND: Awake tracheal intubation is commonly performed with flexible bronchoscopes, but the emerging role of alternative airway devices, such as videolaryngoscopes, direct laryngoscopes, and optical stylets, has been recognised. METHODS: CENTRAL, CINAHL, EMBASE, MEDLINE, and Web of Science were searched for RCTs that compared flexible bronchoscopes, direct laryngoscopes, optical stylets and channelled or unchannelled videolaryngoscopes in adult patients having awake tracheal intubation were included. The co-primary outcomes were first-pass success rate and time to tracheal intubation. Continuous outcomes were extracted as mean and standard deviation, and dichotomous outcomes were converted to overall numbers of incidence. Frequentist network meta-analysis was conducted, and network plots and network league tables were produced. RESULTS: Twelve RCTs were included, none of which evaluated direct laryngoscopes. The first-pass success rate was not different between flexible bronchoscopes, optical stylets, and channelled and unchannelled videolaryngoscopes, with the quality of evidence rated as moderate in view of imprecision. Optical stylets, followed by unchannelled videolaryngoscopes and then felxible bronchoscopes resulted in the shortest time to tracheal intubation, with the quality of evidence rated as high. No differences were shown between the airway devices with respect to the incidence of oesophageal intubation, change of airway technique, oxygen desaturation, airway bleeding, or the rate of hoarseness and sore throat. CONCLUSIONS: Flexible bronchoscopes, optical stylets, and channelled and unchannelled videolaryngoscopes were clinically comparable airway devices in the setting of awake trachela intubation and the time to tracheal intubation was shortest with optical stylets and longest with flexible bronchoscopes.

The External Oblique Intercostal Block: Anatomic Evaluation and Case Series.

STUDY OBJECTIVE: We report a modified block technique aimed at obtaining upper midline and lateral abdominal wall analgesia: the external oblique intercostal (EOI) block. DESIGN: A cadaveric study and retrospective cohort study assessing the potential analgesic effect of the EOI block. SETTING: Cadaver lab and operating room. PATIENTS: Two unembalmed cadavers and 22 patients. INTERVENTIONS: Bilateral ultrasound-guided EOI blocks on cadavers with 29 mL of bupivacaine 0.25% with 1 mL of India ink; single-injection or continuous EOI blocks in patients. MEASUREMENTS: Dye spread in cadavers and loss of cutaneous sensation in patients. MAIN RESULTS: In the cadaveric specimens, we identified consistent staining of both lateral and anterior branches of intercostal nerves from T7 to T10. We also found consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline in patients receiving the EOI block. CONCLUSIONS: We demonstrate the potential mechanism of this technique with a cadaveric study that shows consistent staining of both lateral and anterior branches of intercostal nerves T7-T10. Patients who received this block exhibited consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline. This block can be used in multiple clinical settings for upper abdominal wall analgesia.

The 'haves' and 'have-nots' of personal protective equipment during the COVID-19 pandemic: the ethics of emerging inequalities amongst healthcare workers.

The COVID-19 pandemic has exacerbated inequalities, including among the healthcare workforce. Based on recent literature and drawing on our experiences of working in operating theatres and critical care in the UK's National Health Service during the pandemic, we review the role of personal protective equipment and consider the ethical implications of its design, availability and provision at a time of unprecedented demand. Several important inequalities have emerged, driven by factors such as individuals purchasing their own personal protective equipment (either out of choice or to address a lack of provision), inconsistencies between guidelines issued by different agencies and organisations, and the standardised design and procurement of equipment required to protect a diverse healthcare workforce. These, we suggest, have resulted largely because of a lack of appropriate pandemic planning and coordination, as well as insufficient appreciation of the significance of equipment design for the healthcare setting. As with many aspects of the pandemic, personal protective equipment has created and revealed inequalities driven by economics, gender, ethnicity and professional influence, creating a division between the 'haves' and 'have-nots' of personal protective equipment. As the healthcare workforce continues to cope with ongoing waves of COVID-19, and with the prospect of more pandemics in the future, it is vital that these inequalities are urgently addressed, both through academic analysis and practical action.

Mechanisms of action of the erector spinae plane (ESP) block: a narrative review.

The erector spinae plane (ESP) block is an emerging regional anesthetic technique with significant potential for clinical benefit. Nevertheless, its exact mechanism(s) of action has been much debated. We reviewed the available literature to explore the possible mechanisms of analgesia for the ESP block. These include neural blockade and central inhibition from direct spread of local anesthetic to the paravertebral or epidural space; analgesia mediated by elevated local anesthetic plasma concentrations due to systemic absorption; immunomodulatory effects of local anesthetics; and an effect mediated through the mechanosensory properties of thoracolumbar fascia. Based on evidence from clinical, human cadaveric, animal, and mechanistic laboratory studies, the most probable primary mechanism is a direct effect of local anesthetic via physical spread and diffusion to neural structures in the fascial plane deep to the erector spinae muscles and adjacent tissue compartments. Biological plausibility of this primary mechanism is confirmed by injectate spread to the ventral rami of spinal nerves (though quite variable) in most studies. There is consistent involvement of dorsal rami; epidural spread is a less commonly observed phenomenon. A systemic effect of local anesthetic is also plausible, but unlikely to be a major contributor to clinical analgesic efficacy. The evidence for significant analgesia due to other proposed mechanisms, such as fascia-mediated analgesia or lymphatic spread, are currently limited and thus remain speculative. Understanding the mechanisms of action could assist clinicians in further investigating and refining ESP block performance, with the ultimate goal of optimizing analgesic efficacy and improving postoperative patient outcomes.

RéSUMé: Le bloc du plan des muscles érecteurs du rachis (bloc ESP) est une technique émergente d'anesthésie régionale qui pourrait s'accompagner de bienfaits cliniques considérables. Néanmoins, ses mécanismes d'action exacts font l'objet de nombreux débats. Nous avons passé en revue la littérature disponible pour explorer les mécanismes possibles de l'analgésie par le bloc ESP. Il s'agit notamment du bloc nerveux et de l'inhibition centrale dus à la diffusion directe de l'anesthésique local à l'espace paravertébral ou péridural; de l'analgésie médiée par des concentrations plasmatiques élevées d'anesthésique local dues à son absorption systémique; des effets immunomodulateurs des anesthésiques locaux; et d'un effet médié par les propriétés mécanosensorielles du fascia thoraco-lombaire. Selon les données probantes tirées d'études cliniques, cadavériques, animales, et mécanistes de laboratoire, le mécanisme primaire le plus probable est un effet direct de l'anesthésique local par sa propagation et sa diffusion physique aux structures neuronales dans le plan fascial plus profond que les muscles érecteurs du rachis et aux compartiments tissulaires adjacents. La plausibilité biologique de ce mécanisme primaire est confirmée par la propagation du produit injecté aux rameaux ventraux des nerfs rachidiens (bien que variable) dans la plupart des études. Les rameaux dorsaux sont constamment impliqués; la diffusion péridurale est moins souvent observée. Un effet systémique de l'anesthésique local est également plausible, mais il est peu probable qu'il s'agisse d'un contributeur majeur à l'efficacité analgésique clinique. Les données probantes appuyant une analgésie significative due à d'autres mécanismes proposés, tels que l'analgésie médiée par les fascia ou la propagation lymphatique, sont actuellement limitées et demeurent de l'ordre de la spéculation. En comprenant les mécanismes d'action, les cliniciens pourraient approfondir leurs connaissances et améliorer la performance des blocs ESP, dans le but ultime d'optimiser leur efficacité analgésique et d'améliorer les devenirs postopératoires des patients.

A prospective, observational, cohort study of airway management of patients with COVID-19 by specialist tracheal intubation teams.

PURPOSE: Because of the anticipated surge in cases requiring intensive care unit admission, the high aerosol-generating risk of tracheal intubation, and the specific requirements in coronavirus disease (COVID-19) patients, a dedicated Mobile Endotracheal Rapid Intubation Team (MERIT) was formed to ensure that a highly skilled team would be deployed to manage the airways of this cohort of patients. Here, we report our intubation team experience and activity as well as patient outcomes during the COVID-19 pandemic. METHODS: The MERIT members followed a protocolized early tracheal intubation model. Over a seven-week period during the peak of the pandemic, prospective data were collected on MERIT activity, COVID-19 symptoms or diagnosis in the team members, and demographic, procedural, and clinical outcomes of patients. RESULTS: We analyzed data from 150 primary tracheal intubation episodes, with 101 (67.3%) of those occurring in men, and with a mean (standard deviation) age of 55.7 (13.8) yr. Black, Asian, and minority ethnic groups accounted for 55.7% of patients. 91.3% of tracheal intubations were performed with videolaryngoscopy, and the first pass success rate was 88.0%. The 30-day survival was 69.2%, and the median [interquartile range] length of critical care stay was 11 [6-20] days and of hospital stay was 12 [7-22] days. Seven (11.1%) MERIT healthcare professionals self-isolated because of COVID-19 symptoms, with a total 41 days of clinical work lost. There was one reported incident of a breach of personal protective equipment and multiple anecdotal reports of doffing breaches. CONCLUSION: We have shown that a highly skilled designated intubation team, following a protocolized, early tracheal intubation model may be beneficial in improving patient and staff safety, and could be considered by other institutions in future pandemic surges.

RéSUMé: OBJECTIF: En raison de l'augmentation anticipée du nombre de cas nécessitant une admission à l'unité de soins intensifs, du risque élevé de génération d'aérosols de l'intubation trachéale et des exigences spécifiques aux patients atteints du coronavirus (COVID-19), nous avons créé une équipe mobile dédiée pour l'intubation trachéale rapide (MERIT - Mobile Endotracheal Rapid Intubation Team) afin de garantir qu'une équipe hautement qualifiée puisse être déployée pour prendre en charge les voies aériennes de cette cohorte de patients. Notre objectif était de rapporter l'expérience et l'activité de notre équipe d'intubation ainsi que les devenirs des patients pendant la pandémie de COVID-19. MéTHODE: Les membres de l'équipe MERIT ont suivi un modèle d'intubation trachéale précoce basé sur un protocole. Pendant sept semaines autour du pic de la pandémie, des données prospectives ont été colligées concernant l'activité de la MERIT, les symptômes et diagnostics de COVID-19 parmi les membres de l'équipe, ainsi que les données démographiques, procédurales et les devenirs cliniques des patients. RéSULTATS: Nous avons analysé les données de 150 épisodes d'intubations trachéales initiales, dont 101 (67,3 %) survenus chez des hommes, avec un âge moyen (écart type) de 55,7 (13,8) ans. Les personnes noires, asiatiques et de minorités ethniques représentaient 55,7 % des patients. Au total, 91,3 % des intubations trachéales ont été réalisées par vidéolaryngoscopie, et le taux de réussite au premier essai était de 88,0 %. Le taux de survie à 30 jours était de 69,2 %, et la durée médiane (écart interquartile) de séjour aux soins intensifs était de 11 (6-20) jours et de 12 (7-22) jours à l'hôpital. Sept (11,1 %) professionnels de la santé de l'équipe MERIT se sont mis en auto-isolement en raison de symptômes de la COVID-19, pour un total de 41 jours de travail clinique perdus. Un incident de bris de stérilité de l'équipement de protection individuelle a été rapporté, et de multiples bris lors du déshabillage ont également été rapportés de façon anecdotique. CONCLUSION: Nous avons démontré qu'une équipe d'intubation désignée et hautement qualifiée, respectant un modèle d'intubation trachéale précoce basé sur un protocole, pourrait contribuer à améliorer la sécurité des patients et du personnel. La création d'une telle équipe est envisageable dans d'autres établissements lors de futurs épisodes pandémiques.

Effect of intravenous dexamethasone on the anaesthetic characteristics of peripheral nerve block: a double-blind, randomised controlled, dose-response volunteer study.

BACKGROUND: Intravenous dexamethasone is thought to prolong the duration of peripheral nerve block, but the dose-response relationship remains unclear. The aim of this volunteer study was to evaluate the dose-response effect of i.v. dexamethasone on the prolongation of median nerve block. METHODS: In a double-blind, randomised controlled study, 18 volunteer subjects received two median nerve blocks separated by a washout period. One block was conducted alongside an infusion of saline and the other alongside i.v. dexamethasone 2, 4, or 8 mg. The primary outcome was time to return of normal pinprick sensation. Secondary outcomes included thermal quantitative sensory testing (QST) for the time to return of cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), area under QST curves, grip strength, and the incidence of adverse effects. RESULTS: The primary outcome, time to recovery of pinprick sensation, was similar between volunteers receiving saline or i.v. dexamethasone, regardless of dose (P=0.99). The time to recovery of QST milestones was similar between groups, although area under QST curves indicated prolongation of CDT (0 vs 8 mg, P=0.002) and WDT (0 vs 2 mg, P=0.008; 0 vs 4 mg, P=0.001; 0 vs 8 mg, P<0.001). There was no difference in motor recovery or adverse effects. CONCLUSIONS: Intravenous dexamethasone failed to significantly prolong the duration of pinprick anaesthesia regardless of dose. However, area under QST curve analysis indicated a dose-independent prolongation of CDT and WDT, the clinical significance of which is unclear. CLINICAL TRIAL REGISTRATION: NCT02864602 (clinicaltrials.gov).

Peripheral nerve blockade and novel analgesic modalities for ambulatory anesthesia.

PURPOSE OF REVIEW: Despite peripheral nerve blockade offering analgesic benefits and improving patient satisfaction, it has not been well adopted in ambulatory anesthesia. In this review, we aim to summarize the evidence underlying peripheral nerve blockade, local anesthetic adjuncts, continuous peripheral nerve blockade and novel analgesic modalities, with the objective to provide recommendations on postoperative analgesia optimization after peripheral nerve blockade in an ambulatory setting. RECENT FINDINGS: Barriers to the widespread use of peripheral nerve blockade in ambulatory anesthesia could include lack of education and training, and increased anesthetic induction time. Strategies that have demonstrated promise to increase duration of action and attenuate rebound pain phenomenon after peripheral nerve blockade include multimodal analgesia, local anesthetic adjuncts and continuous infusion of local anesthetic. Dexamethasone has been demonstrated to be the most effective local anesthetic adjunct. Continuous peripheral nerve blockade is a reasonable alternative but at the expense of additional costs and logistical reorganization. There is currently insufficient data to promote the ambulatory use of liposomal bupivacaine, cryoanalgesia and percutaneous peripheral nerve stimulation. SUMMARY: Educational programs and parallel processing may promote peripheral nerve blockade in an ambulatory setting, improving the patient experience in the postoperative period. Intravenous dexamethasone should be considered wherever appropriate as part of a multimodal analgesic strategy to optimize postoperative pain control.

Evidence Basis for Regional Anesthesia in Ambulatory Arthroscopic Knee Surgery and Anterior Cruciate Ligament Reconstruction: Part II: Adductor Canal Nerve Block-A Systematic Review and Meta-analysis.

BACKGROUND: Adductor canal block (ACB) has emerged as an effective analgesic regional technique for major knee surgeries in the last decade. Its motor-sparing properties make it particularly attractive for ambulatory knee surgery, but evidence supporting its use in ambulatory arthroscopic knee surgery is conflicting. This systematic review and meta-analysis evaluates the analgesic effects of ACB for ambulatory arthroscopic knee surgeries. METHODS: We conducted a comprehensive search of electronic databases for randomized controlled trials examining the analgesic effects of ACB compared to control or any other analgesic modality. Both minor arthroscopic and anterior cruciate ligament reconstruction (ACLR) surgeries were considered. Rest and dynamic pain scores, opioid consumption, opioid-related adverse effects, time to first analgesic request, patient satisfaction, quadriceps strength, and block-related complications were evaluated. Data were pooled using random-effects modeling. RESULTS: Our search yielded 10 randomized controlled trials comparing ACB with placebo or femoral nerve block (FNB); these were subgrouped according to the type of knee surgery. For minor knee arthroscopic surgery, ACB provided reduced postoperative resting pain scores by a mean difference (95% confidence interval) of -1.46 cm (-2.03 to -0.90) (P < .00001), -0.51 cm (-0.92 to -0.10) (P = .02), and -0.48 cm (-0.93 to -0.04) (P = .03) at 0, 6, and 8 hours, respectively, compared to control. Dynamic pain scores were reduced by a mean difference (95% confidence interval) of -1.50 cm (-2.10 to -0.90) (P < .00001), -0.50 cm (-0.95 to -0.04) (P = .03), and -0.59 cm (-1.12 to -0.05) (P = .03) at 0, 6, and 8 hours, respectively, compared to control. ACB also reduced the cumulative 24-hour oral morphine equivalent consumption by -7.41 mg (-14.75 to -0.08) (P = .05) compared to control. For ACLR surgery, ACB did not provide any analgesic benefits and did not improve any of the examined outcomes, compared to control. ACB was also not different from FNB for these outcomes. CONCLUSIONS: After minor ambulatory arthroscopic knee surgery, ACB provides modest analgesic benefits, including improved relief for rest pain, and reduced opioid consumption for up to 8 and 24 hours, respectively. The analgesic benefits of ACB are not different from placebo or FNB after ambulatory ACLR, suggesting a limited role of both blocks in this procedure. Paucity of trials dictates cautious interpretation of these findings. Future studies are needed to determine the role of ACB in the setting of local anesthetic instillation and/or graft donor-site analgesia.

The supra-iliac anterior quadratus lumborum block: a cadaveric study and case series.

PURPOSE: The local anesthetic injectate spread with fascial plane blocks and corresponding clinical outcomes may vary depending on the site of injection. We developed and evaluated a supra-iliac approach to the anterior quadratus lumborum (QL) block and hypothesized that this single injection might successfully block the lumbar and sacral plexus in cadavers and provide analgesia for patients undergoing hip surgery. METHODS: Ultrasound-guided bilateral supra-iliac anterior QL blocks were performed with 30 mL of India ink dye in six fresh adult cadavers. Cadavers were subsequently dissected to determine distribution of the dye. In five patients undergoing hip surgery, a unilateral supra-iliac anterior QL block with 25 mL ropivacaine 0.5% followed by a continuous catheter infusion was performed. Patients were clinically assessed daily for block efficacy. RESULTS: The cadaveric injections showed consistent dye involvement of the majority of the branches of the lumbar plexus, including the femoral nerve, lateral femoral cutaneous nerve, ilioinguinal nerve, and iliohypogastric nerve. The majority of cadaveric specimens (83%) also exhibited thoracic paravertebral spread of dye to the T10 level. No specimens showed L5 or sacral nerve root staining or caudal spread below L5. All patients had effective analgesia for total hip surgery and a T11-L3 sensory level following the initial bolus of local anesthetic as well as during the period of continuous catheter infusion. CONCLUSION: This cadaveric study and case series show that a supra-iliac approach to the anterior QL block involved T10--L3 nerve territories and dermatomal coverage with no sacral plexus spread. This technique may have clinical utility for analgesia in hip surgery.

RéSUMé: OBJECTIF: La diffusion de l'anesthésique local injecté lors de la réalisation d'un bloc du fascia et les résultats cliniques qui en découlent peuvent varier selon le site d'injection. Nous avons mis au point et évalué une approche supra-iliaque pour la réalisation d'un bloc du muscle carré des lombes antérieur (quadratus lomburum) et émis l'hypothèse que cette injection unique pourrait suffire à bloquer les plexus lombaire et sacral de cadavres, offrant ainsi une analgésie aux patients subissant une chirurgie de la hanche. MéTHODE: Des blocs bilatéraux du muscle carré des lombes antérieur ont été réalisés par approche supra-iliaque sous échoguidage à l'aide de 30 mL de teinture d'encre de Chine sur six cadavres adultes frais. Les cadavres ont par la suite été disséqués afin de déterminer la diffusion de la teinture. Nous avons réalisé un bloc unilatéral du muscle carré des lombes antérieur par approche supra-iliaque avec une solution de 25 mL de ropivacaïne 0,5 %, suivie d'une perfusion continue via cathéter, chez cinq patients subissant une chirurgie de la hanche. Une évaluation clinique quotidienne des patients a été réalisée afin de déterminer l'efficacité du bloc. RéSULTATS: Les injections sur les cadavres ont permis d'observer une diffusion constante de la teinture dans la majorité des branches du plexus lombaire, y compris dans le nerf fémoral, le nerf fémoral cutané latéral, le nerf ilio-inguinal et le nerf ilio-hypogastrique. Une diffusion paravertébrale thoracique de la teinture jusqu'au niveau T10 a également été retrouvée dans la majorité des spécimens cadavériques (83 %). Aucune coloration au niveau de la racine L5 ou des nerfs sacrés n'a été observée chez les spécimens, ni aucune diffusion caudale au-dessous de L5. Tous les patients ont reçu une analgésie efficace pour une arthroplastie totale de la hanche et obtenu un bloc sensitif au niveau T11­L3 après l'injection du bolus initial d'anesthésique local ainsi qu'au cours de la période de perfusion continue. CONCLUSION: Cette étude cadavérique et cette série de cas montrent qu'une approche supra-iliaque pour réaliser un bloc du muscle du carré des lombes antérieur est parvenue à atteindre les territoires nerveux T10-­L3 et avec couverture de ces dermatomes et ce, sans diffusion au niveau du plexus sacré. Cette technique pourrait avoir une utilité clinique pour l'analgésie en cas de chirurgie de la hanche.

Outcome Selection and Methodological Quality of Major and Minor Shoulder Surgery Studies: A Scoping Review.

BACKGROUND: Core outcome sets aim to select and standardize the choice of important outcomes reported in clinical trials to encourage more effective data synthesis, increase the reliability of comparing results, and minimize reporting bias. A core outcome set for elective shoulder surgery has yet to be defined, and therefore a systematic assessment of outcomes and methodology is necessary to inform the development of a core outcome set. QUESTIONS/PURPOSES: The purpose of this study was to examine randomized controlled trials (RCTs) of patients having elective major or minor shoulder surgery to (1) identify the outcome domains reported; (2) determine specific outcome measurement tools that were utilized; and (3) assess the work for methodological quality and risk of bias. METHODS: We conducted a scoping review (a review that identifies the nature and extent of research evidence) to explore the reported outcome domains, outcome tools, and methodological quality from RCTs conducted in shoulder surgery. We considered both major shoulder surgery (defined as arthroplasty, rotator cuff repair, stabilization procedures, biceps tenodesis, or Bankart repairs) and minor shoulder surgery (simple arthroscopy, capsular plication, lateral clavicular excisions, or subacromial decompression). We queried 10 electronic databases for studies published between January 2006 and January 2015. Studies were included if they were prospective, randomized controlled, clinical trials enrolling patients who received an elective shoulder surgical intervention. We extracted data relating to trial characteristics, primary outcomes, tools used to measure these outcomes as well as methodological quality indicators. We assessed indicators of methodological quality by exploring (1) the reproducibility of power analyses; and (2) whether the primary outcomes were powered to minimum clinically important differences. Risk of bias was also assessed with the Jadad score with scores between 0 (very high risk of bias) and 5 (very low risk). Findings were qualitatively analyzed and reported according to systematic and scoping review guidelines. We included 315 studies involving 30,232 patients; 266 studies investigated anesthetic, analgesic, or surgical interventions. RESULTS: Of the 315 studies included, the most common outcome domains evaluated were analgesic (n = 104), functional (n = 87), anesthetic (n = 56), and radiologic (n = 29) outcomes, with temporal patterns noted. Studies of major shoulder surgery most commonly reported functional primary outcome domains, whereas minor shoulder surgery studies most frequently reported analgesic primary outcome domains. There were 85 different primary outcome tools utilized, which included 20 functional, 20 anesthetic, 13 analgesic, and 12 radiologic. A methodological quality assessment revealed that 24% of studies had reproducible power analyses, 13% were powered to minimum clinically important differences, and risk of bias assessment demonstrated a median (interquartile range [range]) Jadad score of 4 (3-5 [1-5]). CONCLUSIONS: A wide range of outcome domains and outcome assessment tools are in common use in contemporary trials of patients undergoing elective surgery. Although some diversity is important to allow the assessment of patient populations that may have different goals, the large number of tools in common use may impair the ability of future meta-analyses to pool results effectively or even for systematic reviews to synthesize what is known. The limitations of methodological quality in RCTs may be improved by researchers following standard guidelines and considering the minimum clinically important differences in their trials to be of greater use to clinicians and their patients. LEVEL OF EVIDENCE: Level I, therapeutic study.

Regional anesthesia by nonanesthesiologists.

PURPOSE OF REVIEW: As the evidence supporting the notion that regional anesthesia improves patient outcomes grows, utilization of regional anesthesia techniques has similarly increased. Best care should not be restricted by the background of care providers, however, the evidence replicating benefits of regional anesthesia when it is delivered by nonanesthesiologists is unclear. In this review, the provision of regional anesthesia by nonanesthesiologists is discussed so that readers can come to their own conclusions. RECENT FINDINGS: Regional anesthesia procedures are performed by nonanesthesiology physicians such as emergency physicians, critical care specialists, and surgeons. Patients benefit from the provision of regional anesthesia by these groups, but inconsistencies exist in training, service provision, and collaboration between these specialties and anesthesiologists. Nonphysician anesthesia providers also provide regional anesthesia. There are limited data on outcomes or benefits of this nonphysician-provided service, but consideration of team-based care and alternative models of care based upon geographical need is worthwhile. SUMMARY: The provision of regional anesthesia requires the accumulation of a suitable knowledge, skills, and behaviors that can be taught. Whilst it may not be appropriate for all techniques to be performed by all individuals, the possession of these competencies with the appropriate training and quality assurance means that more patients may ultimately benefit from the provision of regional anesthesia services.