Cumulative Sum Analysis for Spinal Blockade in Novices

Objectives: To create CUSUM learning curves for spinal blockade in novices with less than 3 years’ anaesthetic experience and to determine the minimal number of attempts it takes to achieve competency. Method: During the period June 2021 to March 2022, 5 trainees accomplished a total of 308 spinal blockades. Of the 308 that were done, 226 were used for data analysis as this figure had correlating data collection forms 1 and 2. (see supplementary files) CUSUM learning curves were created using acceptable and unacceptable failures rates determined from a consultant consensus (see supplementary files), and success and failure criteria were obtained from the literature. Result: 60% of trainees achieved an 85% success rate (as determined by consultant consensus) with a median of 17 spinal blockades.The true failure rate (47.5%) was higher than the acceptable failure rate (15%). Hence for 60% trainees to be deemed competent with a 52.5% success rate, 17 (15-34) spinal blockades must be performed. Conclusion: CUSUM learning curves are a useful replacement to logbooks and work based assessments in determining progress and competency of trainees. More work needs to be done to obtain failure rates of expert anaesthetists in this country, so we can define acceptable and unacceptable failure rates for our population of trainees at the various institutions. Setting such standards nationally would aid the move towards competency-based training.