Craniocaudal spread and clinical translation for combined erector spinae plane block and retrolaminar block in soft embalmed cadavers: a randomised controlled equivalence study.

BACKGROUND: Erector spinae plane (ESP) block spread can be unpredictable. We previously improved the spread of ESP injection by addition of retrolaminar (RL) injection. However, it is not clear whether spread at high thoracic levels is similar to spread at midthoracic levels. Our primary objective was to demonstrate that craniocaudal dye spread was equivalent after combined ESP and RL injection using a 19 G Tuohy needle at the third (T3) and sixth (T6) vertebrae in soft embalmed Thiel cadavers. METHODS: We randomised 20 combined ESP and RL injections to the T3 and T6 vertebral levels on both sides of 10 prone Thiel cadavers. A 3-8 MHz transducer was placed in the paramedian sagittal plane and a single anaesthetist injected 10 ml dye onto the transverse process, then 10 ml dye onto the laminae of T3 or T6. Cadavers were dissected 24 h later. RESULTS: Mean (sd) craniocaudal spread of dye after combined ESP + RL injection at T3 and T6 vertebral levels was equivalent: 8.6 (1.8) vs 8.7 (2.3) levels, respectively; difference (90% confidence interval): -0.1 (-1.4 to 1.6), P=0.904. Dye extended uniformly, cranially and caudally, from the point of injection. A 3D prosection created from a Thiel cadaver confirmed that the dorsal ramus emerges from the costotransverse foramen deep to the intertransverse ligament within the retro-superior costotransverse ligament space. Combined ESP and RL block in six patients before mastectomy achieved extensive anterior, lateral, and posterior chest wall paraesthesia over four to six dermatomes. CONCLUSIONS: Combined ESP and RL injections showed equivalent and consistent spread at T3 and T6 injection sites. A pilot study confirmed translation to patients.

Patterns of Skills Acquisition in Anesthesiologists During Simulated Interscalene Block Training on a Soft Embalmed Thiel Cadaver: Cohort Study.

BACKGROUND: The demand for regional anesthesia for major surgery has increased considerably, but only a small number of anesthesiologists can provide such care. Simulations may improve clinical performance. However, opportunities to rehearse procedures are limited, and the clinical educational outcomes prescribed by the Royal College of Anesthesiologists training curriculum 2021 are difficult to attain. Educational paradigms, such as mastery learning and dedicated practice, are increasingly being used to teach technical skills to enhance skills acquisition. Moreover, high-fidelity, resilient cadaver simulators are now available: the soft embalmed Thiel cadaver shows physical characteristics and functional alignment similar to those of patients. Tissue elasticity allows tissues to expand and relax, fluid to drain away, and hundreds of repeated injections to be tolerated without causing damage. Learning curves and their intra- and interindividual dynamics have not hitherto been measured on the Thiel cadaver simulator using the mastery learning and dedicated practice educational paradigm coupled with validated, quantitative metrics, such as checklists, eye tracking metrics, and self-rating scores. OBJECTIVE: Our primary objective was to measure the learning slopes of the scanning and needling phases of an interscalene block conducted repeatedly on a soft embalmed Thiel cadaver over a 3-hour period of training. METHODS: A total of 30 anesthesiologists, with a wide range of experience, conducted up to 60 ultrasound-guided interscalene blocks over 3 hours on the left side of 2 soft embalmed Thiel cadavers. The duration of the scanning and needling phases was defined as the time taken to perform all the steps correctly. The primary outcome was the best-fit linear slope of the log-log transformed time to complete each phase. Our secondary objectives were to measure preprocedural psychometrics, describe deviations from the learning slope, correlate scanning and needling phase data, characterize skills according to clinical grade, measure learning curves using objective eye gaze tracking and subjective self-rating measures, and use cluster analysis to categorize performance irrespective of grade. RESULTS: The median (IQR; range) log-log learning slopes were -0.47 (-0.62 to -0.32; -0.96 to 0.30) and -0.23 (-0.34 to -0.19; -0.71 to 0.27) during the scanning and needling phases, respectively. Locally Weighted Scatterplot Smoother curves showed wide variability in within-participant performance. The learning slopes of the scanning and needling phases correlated: ρ=0.55 (0.23-0.76), P<.001, and ρ=-0.72 (-0.46 to -0.87), P<.001, respectively. Eye gaze fixation count and glance count during the scanning and needling phases best reflected block duration. Using clustering techniques, fixation count and glance were used to identify 4 distinct patterns of learning behavior. CONCLUSIONS: We quantified learning slopes by log-log transformation of the time taken to complete the scanning and needling phases of interscalene blocks and identified intraindividual and interindividual patterns of variability.

Validity and reliability of metrics for translation of regional anaesthesia performance from cadavers to patients.

BACKGROUND: Our goal is to develop metrics that quantify the translation of performance from cadavers to patients. Our primary objective was to develop steps and error checklists from a Delphi questionnaire. Our second objective was to show that our test scores were valid and reliable. METHODS: Sixteen UK experts identified 15 steps conducive to good performance and 15 errors to be avoided during interscalene block on the soft-embalmed cadaver and patients. Thereafter, six experts and six novices were trained, and then tested. Training consisted of psychometric assessment, an anatomy tutorial, volunteer scanning, and ultrasound-guided needle insertion on a pork phantom and on a soft-embalmed cadaver. For testing, participants conducted a single interscalene block on a dedicated soft-embalmed cadaver whilst wearing eye tracking glasses. RESULTS: We developed a 15-step checklist and a 15-error checklist. The internal consistency of our steps measures were 0.83 (95% confidence interval [CI]: 0.78-0.89) and 0.90 (95% CI: 0.87-0.93) for our error measures. The experts completed more steps (mean difference: 3.2 [95% CI: 1.5-4.8]; P<0.001), had less errors (mean difference: 4.9 [95% CI: 3.5-6.3]; P<0.001), had better global rating scores (mean difference: 6.8 [95% CI: 3.6-10.0]; P<0.001), and more eye-gaze fixations (median of differences: 128 [95% CI: 0-288]; P=0.048). Fixation count correlated negatively with steps (r=-0.60; P=0.04) and with errors (r=0.64; P=0.03). CONCLUSIONS: Our tests to quantify ultrasound-guided interscalene nerve block training and performance were valid and reliable.

Sudden severe postoperative dyspnea following shoulder surgery: Remember inadvertent phrenic nerve block due to interscalene brachial plexus block.

Advanced imaging techniques, improved operative techniques, and instrumentation combined with better patient awareness and expectations have resulted in an exponential increase in upper limb surgical procedures during recent times. Surgical teams expect superior analgesia and regional blocks have matched these expectations quite often resulting in improved patient satisfaction and early rehabilitation to achieve best results. Ultrasound-guided interscalene brachial plexus block (ISB) is commonly used to provide analgesia for procedures involving shoulder girdle. We report a case of symptomatic hemi-diaphragmatic paresis (HDP) due to the phrenic nerve block following ISB for arthroscopic sub-acromial decompression of the shoulder presenting as severe postoperative dyspnea. There is strong evidence of HDP following ISB in anesthetic literature, but not reported in related surgical specialties such as orthopedics. We wish to inform upper-limb surgeons and educate junior doctors and other ancillary staff working in upper-limb units to be aware of this serious but reversible complication.

Invasive pulmonary aspergillosis post extracorporeal membrane oxygenation support and literature review.

The use of extracorporeal membrane oxygenation (ECMO) for reversible pulmonary failure in critically ill patients has increased over the last few decades. Nosocomial infections are a major complication of ECMO and fungi have been found to be a common cause. Herein, we describe a case of invasive pulmonary aspergillosis following ECMO, which was successfully treated with combination antifungal therapy and interferon-gamma.