Refreshing iv cannulation skills using mental imagery in medical students: Rater-blinded three-arm intervention

Background and Goal of Study:
Mental imagery has long been used to successfully improve top athletes’ performance during e.g. the Olympics. More recently, this educational strategy has also been used to learn surgical skills. Only a few studies describe the use of mental imagery in anesthesia and in undergraduate medical education. This study investigates the effectiveness of mental imagery compared to written instructions respectively to hands-on training in part-task trainers in maintaining the skills of intravenous cannulation on a part task trainer in first-year medical students.

Materials and Methods: We performed a single-center, rater-blinded randomized controlled trial. Students attended a compulsory 4h- instructor-led intravenous cannulation course six month before the trial. After ethics committee waiver but with written informed consent, first-year medical students were randomly assigned to one of three different six-minutes tutorials on intravenous cannulation six months after the i.v. cannulation course. Each group consisted either of self-learning tutorial based on written instructions, a hands-on iv cannulation tutorial on a manikin, or a tutorial with a mental imagery audioguide session.
The student´s performance was assessed with the use of a 15-item standardized checklist in a six-minute Objective Structured Clinical Examination station for intravenous cannulation. Assuming an alpha error of 0.01, and an effect size of a Cohen’s f of 0.305 with an aimed power of 0.80, our sample size resulted in a minimum of 156 students. We performed descriptive analysis of the data and a one-way ANOVA. An a priori probability of less than 0,05 was considered to be statistically significant. All data were analysed using SPSS v.27.

Results and Discussion: In the 309 students participating, we did not find differences in the performance between the three groups and the pass mark for the OSCE station. The internal consistency of station items was 0.691. The mental imagery group was as successful as both other groups. With the same outcome, mental imagery and written instruction have the better effort-return ratio compared to resource intensive hands-on training in part-task trainers.

Conclusion: Simple and short interventions with mental imagery and written instructions have been shown equal effective as hands-on exercises for refreshing a simple but important procedural skill in medical students.