Visuospatial ability and novice brachial plexus sonography performance.

BACKGROUND: The knowledge on the type and influence of visuospatial ability on sonography performance relevant for ultrasound-guided regional anaesthesia remains incomplete. The aim of this study was to determine whether four different factors of visuospatial ability are important in determining proficiency and procedure time of novices performing brachial plexus sonography. These factors were spatial visualisation, flexibility of closure, spatial relations and speed of closure. METHODS: Thirty-three ultrasound novices were recruited in this prospective, observational trial. Five cognitive tests, from a standardised battery that assesses all four visuospatial factors, were administered to each participant at the start of the study. Each novice then performed brachial plexus sonography on a human model at baseline and final exams, separated by a discovery learning session. Novices were examined in their sonography performance by blinded assessors who scored proficiency, technique, image quality, and time taken to perform at both baseline and final scans. RESULTS: Novices with intermediate and high visuospatial ability in spatial visualisation, spatial relations and speed of closure were significantly more proficient and efficient compared with their peers stratified into low-ability cohorts (P < 0.02). The Matrix Reasoning and the Mental Rotations Test-A were both correlated with sonography final exam scores (Spearman rank correlation ρ = 0.38 and 0.36, P = 0.03 and 0.04, respectively). CONCLUSIONS: Spatial visualisation, spatial relations and speed of closure, but not flexibility of closure, influence sonography performance. Visuospatial ability testing can identify novices who will require extra assistance in learning ultrasound relevant for regional anaesthesia. ( TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry 12614000819628).

A randomised controlled trial comparing meat-based with human cadaveric models for teaching ultrasound-guided regional anaesthesia.

The aim of this prospective, blinded, randomised controlled study was to compare novices' acquisition of the technical skills of ultrasound-guided regional anaesthesia using either a meat phantom model or fresh-frozen human cadavers. The primary outcome was the time taken to successfully perform an ultrasound-guided sciatic nerve block on a cadaver; secondary outcomes were the cumulative score of errors, and best image quality of the sciatic nerve achieved. After training, the median (IQR [range]) time taken to perform the block was 311(164-390 [68-600]) s in the meat model trained group and 210 (174-354 [85-600]) s in the fresh-frozen cadaver trained group (p = 0.24). Participants made a median (IQR [range]) of 18 (14-33 [8-55]) and 15 (12-22 [8-44]) errors in the two groups respectively (p = 0.39). The image quality score was also not different, with a median (IQR [range]) of 62.5 (59.4-65.6 [25.0-100.0])% vs 62.5 (62.5-75.0 [25.0-87.5])% respectively (p = 0.58). The training and deliberate feedback improved all participants' block performance, the median (IQR [range]) times being 310 (206-532 [110-600]) s before and 240 (174-354 [85-600]) s after training (p = 0.02). We conclude that novices taught ultrasound scanning and needle guidance skills using an inexpensive and easily constructed meat model perform similarly to those trained on a cadaveric model.