Participants and setting
Nine volunteer GIM clinician-educators at an academic health center participated in a 6-month POCUS curriculum with a goal of developing core faculty for a residency program. Faculty did not receive protected time from other duties. Figure 1 illustrates the structure and content of the faculty development curriculum, including elements that were eligible for continuing medical education (CME) credit. The introductory workshop was required, but all other curricular elements were voluntary. Subsequent lectures and workshops were scheduled to accommodate as many participants as possible. Before these sessions, participants were asked to review relevant online modules from free open-access medical education resources. Modules were typically 10–15 min in duration. In-person didactics were recorded and posted to an online learning management system for asynchronous review. Peer-group practice was arranged by group members.
GIM faculty performance was compared to three senior cardiology fellows who had completed level 1 echocardiography training [11], including performance of 75 comprehensive echocardiographic studies. Three registered diagnostic cardiac sonographers (DCS) served as the gold standard.
Evaluation
We scored FCU exams using a validated image acquisition assessment tool [12]. As in the validation study, our primary outcome was an FCU efficiency score, calculated by dividing an image quality score by exam duration in minutes. The original 68-point image quality score was modified to 66-points, as two scoring items were not taught (inferior vena cava M-mode and respiratory variation measurement). The scoring instrument was comprised of two sections. The first section included scoring of anatomic structures and image optimization (appropriate depth, gain, and centering) in the following views: parasternal long axis; parasternal short-axis aortic valve, mitral valve, mid-papillary, and apex; apical four chamber; subcostal long axis; and subcostal inferior vena cava (IVC). The second section scored the overall diagnostic image quality of the exam for common clinical questions, such as left ventricular systolic function. Assessments took place after completion of an 8-h introductory workshop (baseline), at 3 months, and at 6 months. FCU exams were performed on the same three standardized patients (SPs) at each session. The research team chose SPs that represented a cross-section of typical IM patients (two women, age 48–79 years, body mass index 23–39 kg/m2). One SP had a hiatal hernia, which was not known prior to the research sessions. Using cart-sized point-of-care ultrasound machines (Sparq; Philips Healthcare, Andover, MA), participants captured video loops in the required views, outlined above. Before each session, written instructions were provided to participants, facilitators, and SPs (Additional file 1: Appendix S1). The machines used for the assessment were the same as those available to GIM faculty during their curriculum. Before each assessment session, the cardiology fellows and DCS received an in-person tutorial on machine set-up and knobology. Two board-certified cardiologists scored the FCU exams. They were blinded to participant group, SP, and exam session. Prior to scoring research images, they scored three pilot exams together to ensure similar application of the scoring instrument. They then independently scored two pilot exams, resulting in nearly identical scores (53 vs. 52 and 41.5 vs. 42.5 points).
Analysis
Mean FCU efficiency scores, image quality total score, image quality sub-group scores, and exam duration were compared using a linear mixed effects model with random effects for SP and participant and fixed effects for session and group (GIM faculty, cardiology fellows, and DCSs). If the interaction of group and session were statistically significant, Tukey’s test was performed to make pairwise comparisons of the mean scores between the three groups for each session. If the interaction of group and session was not significant, pairwise comparisons were performed between the groups (combining sessions) and between the sessions (combining groups). Model adjusted means and standard errors (SE) were used for descriptive statistics. Spearman correlation coefficients were used to assess the association of total CME hours with efficiency score. p < 0.05 was considered statistically significant. Statistics were calculated using SAS Version 9.4 software (SAS Inc., Cary, NC). The University of Nebraska Medical Center Institutional Review Board approved the study (163-16-EX).