Education and training in ultrasound-guided regional anaesthesia
thesisposted on 28.03.2022, 09:52 authored by Alwyn Hooi Hock Chuan
The concept of using Doppler ultrasound to guide regional anaesthesia performance was first described in 1978. It was, however, the introduction into clinical practice in the last 15 years of portable, affordable, high resolution, bedside ultrasound machines that has revolutionised the practice of regional anaesthesia. Visualising anatomical structures, and guiding a needle to target structures under direct ultrasound guidance, is now considered best practice. Ultrasound-guided regional anaesthesia, compared to traditional nerve localisation techniques such as nerve stimulation and paraesthesia, has been shown to improve efficacy and efficiency, and reduce the risk of local anaesthesia systemic toxicity and pneumothorax. Ultrasound has allowed the introduction of novel approaches to thoracoabdominal and neuraxial blocks. This imaging technique is increasingly being used in pain medicine, complementing and in some instances replacing, the image intensifier and computed tomography-guided interventional procedures. In contrast, novices attempting ultrasound guided regional anaesthesia exhibit suboptimal behaviours, including visual-spatial disorientation, rigid procedural thinking, and needle manipulation without confirmation of positioning. The root problem is that teaching of regional anaesthesia is variable in quality and is non-systematic. The reasons are complex, but include variability in supervision, worsening production pressures in busy tertiary hospitals curtailing time for teaching, shortening of trainee training times, and resistance by clinicians for new techniques. Compounding these problems was a lack of validated, reliable and objective tools to assess ultrasound-guided regional anaesthesia performance. This is addressed in the first four studies of this thesis. Studies 1 and 2 evaluated the psychometric properties of the direct observation of procedural skills assessment tool used in the current training curriculum of the Australian and New Zealand College of Anaesthetists. I found that inter-assessor reliability is poor, which has important consequences as this tool is used for trainee assessment and structured feedback. Study 3 evaluated a checklist and global rating scale designed specifically for ultrasound-guided regional anaesthesia. This tool showed good construct validity, and that a deconstructed, itemised checklist is useful for teaching complex skills such as regional anaesthesia. Study 4 described the design, creation, and validation of the Regional Anaesthesia Procedural Skills (RAPS) assessment tool. RAPS has evidence for face validity, construct validity, test-retest reliability, external reliability, and feasibility as an assessment tool for all regional anaesthesia blocks, including ultrasound-guided techniques. The RAPS tool can thus be used for clinical assessment of trainees, as well as a reliable measure of performance in participants in education research. The next two studies investigated factors by which training in ultrasound-guided regional anaesthesia can be improved. Study 5 was a randomised controlled trial comparing whether fresh-frozen human cadavers were superior to meat-based models for teaching ultrasoundguided regional anaesthesia. I found that while face validity and qualitative satisfaction was superior for cadavers, there was no quantitative difference in efficacy, efficiency or errors committed in a part-task technical skills test. Study 6 was an exploratory study in whether visuospatial ability influences sonography performance. In novices performing brachial plexus sonography and reliant only on discovery learning, three visuospatial factors were found to be influential: spatial visualisation, spatial relations, and speed of closure. The standardised visuospatial test battery can thus identify novices who will likely struggle with sonography. This opens an avenue for training tailored to an individual's strengths and weaknesses.