A clinical assessment tool for ultrasound-guided axillary brachial plexus block

Competency in anesthesia traditionally has been determined subjectively in practice. Optimal training in procedural skills requires valid and reliable forms of assessment. The objective was to examine a procedure-specific clinical assessment tool for ultrasound-guided axillary brachial plexus block for inter-rater reliability and construct validity in a clinical setting.

This was a prospective observational study. Using prior work at our institution, the clinical assessment tool was developed consisting of a 63-point task-specific checklist and a global rating scale. The anesthesiologists were assigned to three groups based on prior experience of performing an axillary block: group 1 ('novices') < 10 procedures, group 2 ('intermediates') 50-80 procedures and group 3 ('experts') > 100 procedures. Each participant performed two consecutive blocks that were videotaped. Two blinded independent experts trained in the marking of the tool evaluated the videotapes.

There were five participants per group. The inter-rater reliability between assessors was 0.842 and 0.795 for the checklist and global rating scale, respectively. There was a consistent difference between (each pair of) the three groups in terms of both the checklist and global rating scale (P < 0.05). For the checklist, expert vs. intermediate group P = 0.023, expert vs. novice group P < 0.001 and intermediate vs. novice group P = 0.019. For the global rating scale, expert vs. intermediate group P < 0.001, expert vs. novice group gave P < 0.001 and intermediate vs. novice group P = 0.023.

The objective of task-specific checklist and global rating scale are reliable and valid measures of axillary block performance between different levels of expertise.