In this randomized controlled trial following a hands-on heart and lung POCUS course, we tested a 6-month structured POCUS tutoring program versus usual practice in internal medicine residents. In the intervention arm, there was a significant increase in the proportion of residents obtaining at least 25 supervised examinations and in the absolute number of supervised POCUS examinations. This trial succeeds to prove the feasibility and superiority of a tutoring program for POCUS supervision in comparison to the standard of practice in our and many institutions. Whereas participants in control group were strongly encouraged to seek supervision, only a few of them did so. Indeed, low rate of practice is usually observed after practical POCUS courses, as reported in a previous study in which only 6% of participants performed 30 examinations six months after the course (9).
Interestingly, the increased number of prompted examinations appears to enhance perceived and observed proficiency in heart but not lung US. In contrast to our observations concerning the skills in lung US, a previously published study including 28 internal medicine residents, randomized to a standard POCUS curriculum (i.e. a half-day theoretical and practical course followed by 5 one-hour lecture and hands-on sessions) versus 20 additional hours of bedside supervision focused on lung US has demonstrated a significant increase in proficiency in the intervention group after 6 months (15). Divergence in results may be related to the level of assessed competency complexity: participants were asked to demonstrate 23 different lung US competencies, whereas only three simple lung competencies were tested by our assessment tool and were reached by most participants in both groups. The benefit of a structured supervision may thus be particularly important for the acquisition of complex POCUS skills. Considering the maintenance of complex POCUS skills, our observation of the loss in the perceived global competencies regarding heart ultrasound in the control group (Supplementary table 4) was also observed in previous studies. In a prospective cohort study including 23 medical students trained in POCUS examination (didactic lectures and hands-on practice on healthy volunteers), the authors reported a decline in image acquisition skills for heart (i.e. parasternal short and long axis, IVC) but not lung US (i.e. lung sliding) (8) Another randomized controlled trial involving 21 critical care fellows failed to demonstrate a statistically significant rise in 6-month POCUS knowledge and skills following 8-hour of refresh training, incorporating 6 hours of scheduled bedside supervision (assessment tool ranging from 0 to 200 points, higher value indicating greater competence). It is worth noting that all participants were enrolled in a fellowship POCUS curriculum, which encompassed learning modules, in-class lectures, and hands-on training, resulting in an increase in competency scores for all participants. This increase was more pronounced in the intervention group but the between-group difference did not reach statistical significance, possibly due to insufficient statistical power (median increase of 18 (IQR, 3.8 to 38) versus 31 (IQR, 21 to 46) in control and intervention group respectively, p = 0.09).(16)
Critical care physicians were the pioneers in POCUS implementation and previous studies focused mostly on critical care fellows (16, 17). Our study is notable for implementing POCUS tutoring during internal medicine residency, a setting with lower level of familiarity with POCUS. The availability of devices and the exposure to a favourable environment for ultrasound utilisation is important for supporting the acquisition of skills. In our subgroup analysis, we observed an incremental benefit when residents were in a clinical rotation with higher availability of US devices (i.e. emergency, critical care and internal medicine). Ultrasonography devices alone without supervision slots are however insufficient, as demonstrated by the extremely low rate of POCUS examinations in control group, despite a greater proportion of participants with favourable rotations. Two previous trials of internal medicine residents randomized to receive personal handheld US devices or not, observed no differences in skills acquisition(18, 19) Consequently, to facilitate skills acquisition in POCUS and to maintain proficiency, in addition to basic training, students should benefit from structured supervision in an environment conducive to the application of this knowledge and equipped with the necessary tools for this task.
Our study has some limitations. First, the study was powered only for the primary outcome and secondary outcomes must be considered as exploratory, due to the small sample size. Second, supervision time slots were scheduled in addition to clinical activity; unavailability of tutors or trainees may have influenced the success rate, even if this is expected to lower the magnitude of the observed effect. Clinical POCUS rotations with dedicated time has been suggested as a valuable solution and must be explored in further trials(20). Third, both groups experienced drop-outs due to maternity leave, reflecting the pragmatic design of the trial. However, results maintained statistical significance in our worst-case scenario sensitivity analysis.
Our study has several strengths. First, while the use of POCUS in internal medicine is experiencing exponential growth, there are few studies addressing the challenge of achieving and maintaining proficiency. This study contributes to the subject with high quality data. Second, participants underwent a rigorous and comprehensive learning process, overseen by a team of supervisors, all certified by the Swiss Society of Ultrasound in Medicine (https://sgum-ssum.ch/, Supplementary Table 3). Third, in contrast to prior studies, external POCUS experts were involved in the study to maintain assessor blinding and mitigate the risk of bias, thereby reinforcing the robustness of our assumptions.
In conclusion, our findings highlight the feasibility and need for a structured supervision following a hands-on course to improve both the use and proficiency of POCUS, especially for complex tasks and POCUS applications requiring advanced visuospatial skills, such as focused echocardiography.
The low level of supervised examinations and competency in the control group raises serious doubts regarding the relevance of POCUS single courses without further supervision. Structured POCUS tutoring can significantly enhance training and practice, providing a solid foundation for a practical and safe use of POCUS. Dedicated supervision time slots for trainees during acute medicine clinical rounds may further increase the success rate.