The effect of content knowledge and repeated teaching on teaching and learning basic life support: a cluster randomised controlled trial.

Background: Experimental research on the training of BLS instructors and how their performance evolves is scarce. This study investigated the role of content knowledge and repeated teaching trials for improving teaching and learning Basic Life Support (BLS).

Methods: A cluster randomised controlled trial. Six secondary school teachers were assigned to either a common content knowledge (CCK) or specialised content knowledge (SCK) training. In the CCK group, teachers were taught to perform BLS technically correct. In the SCK group, teachers were additionally taught to detect and correct common errors students would make. Following the training, teachers taught two BLS lessons to two different classes of secondary school students ( = 216, age 12-14). Teachers' lesson organisation in terms of cognitive (e.g. task presentations), motor (e.g. practice time), and general (e.g. getting organised) activities was assessed. Students' BLS and CPR performance was assessed as the primary outcomes.

Results: BLS performance was significantly higher in the second lesson for students taught by SCK versus CCK teachers (73% vs 63%). No significant difference was detected between lesson one and two across conditions and teachers. For cardiopulmonary resuscitation (CPR) variables, significant differences in favour of the SCK condition were found for chest compression depth after lesson one, and the amount and volume of ventilations after lesson two.

Conclusion: Students' BLS and CPR performance was positively impacted by the SCK training. BLS performance varied greatly by teachers with averages ranging from 53% to 83% across conditions. Results suggest teaching experience alone is not sufficient to improve teaching effectiveness.