Optimal refresher training intervals for AED and CPR skills: a randomised controlled trial.

AIM: To determine the optimal refresher training interval for lay volunteer responders in the English National Defibrillator Programme who had previously undertaken a conventional 4-h initial class and a first refresher class at 6 months. METHODS: Subjects were randomised to receive either two additional refresher classes at intervals of 7 and 12 months or one additional refresher class after 12 months. RESULTS: Greater skill loss had occurred when the second refresher class was undertaken at 12 compared with 7 months. Skill retention however, was higher in the former group, ultimately resulting in no significant difference in final skill performance. There was no significant difference in performance between subjects attending two versus three refresher classes. On completion of refresher training all subjects were able to deliver countershocks, time to first shock decreased by 17s in both groups, and the proportion of subjects able to perform most skills increased. The execution of several important interventions remained poor, regardless of the total number of classes attended or the interval between them. These included CPR skills, defibrillation pad placement, and pre-shock safety checks. Refresher classes held more frequently and at shorter intervals increased subjects' self-assessed confidence, possibly indicating greater preparedness to use an AED in a real emergency. CONCLUSIONS: This study shows that the ability to deliver countershocks is maintained whether the second refresher class is held at seven or 12 months after the first. To limit skill deterioration between classes, however, refresher training intervals should not exceed 7 months. The quality of instruction given should be monitored carefully. Learning and teaching strategies require review to improve skill acquisition and maintenance.