The Impact of Retraining on Medium-Term (4-Month) Skill Retention Among PGY-1 and -2 Residents in a Cardiac Point-of-Care Ultrasound Curriculum: A Pilot Study

Technical Summary: The Impact of Retraining on Medium-Term Skill Retention in Cardiac POCUS

Problem Statement
Medical education in cardiac point-of-care ultrasound (POCUS) faces a persistent challenge: the decay of psychomotor skills following a single training session. While short-term benefits of cardiac POCUS curricula are well-documented, evidence regarding medium- and long-term skill retention remains limited. Previous studies by the authors and others have demonstrated significant skill decline within two months of initial training. This decay parallels issues seen in Advanced Cardiac Life Support (ACLS) training, where the American Heart Association (AHA) recommends replacing massed practice (single sessions) with spaced practice (interval retraining) to counteract deterioration. The specific educational gap addressed in this pilot study is whether a spaced practice curriculum, incorporating a brief retraining session two months after initial training, can mitigate skill decay among Postgraduate Year (PGY) 1 and 2 residents over a four-month period. Additionally, the study seeks to determine which pre-training competency levels benefit most from this specific retraining model.

Methodology
This was a prospective, single-group, pre-post educational intervention study with blinded outcome assessment, conducted at a teaching hospital in Japan between April 2021 and March 2023.

• Participants: All 26 eligible PGY-1 and PGY-2 residents were enrolled.
• Curriculum Design: The intervention utilized a spaced practice framework:
  1. Pre-training: Self-study via online modules (ASE and author-created).
  2. Initial Training: A 2-hour hands-on session involving a 30-minute lecture and 90 minutes of supervised practice on a simulator and a healthy volunteer using a hand-held ultrasound (Butterfly iQ).
  3. Retraining: Two months post-initial training, participants underwent a recorded skill test followed by a 10-minute, one-on-one retraining session with direct feedback on their recorded videos.
  4. Assessment Timeline: Image acquisition skills were assessed at four junctures: pre-training, immediately post-training, 2-months post-training (pre-retraining), and 4-months post-training.
• Skill Assessment: Participants demonstrated acquisition of five cardiac views (PLAX, PSAX, A4C, S4C, SIVC) on a healthy volunteer. A validated 10-point scoring system (0–2 points per view) rated image quality (Excellent, Acceptable, Poor) by three blinded cardiologists.
• Analysis: Mean score differences were calculated using mixed-effects models. Post-hoc subgroup analyses classified participants into beginner (<5), intermediate (5 to <8), and advanced (≥8) based on pre-training scores.

Key Results

• Overall Skill Trajectory:
  • Pre- to Immediate Post-training: Mean scores increased significantly from 6.03 (intermediate) to 8.69 (advanced), a difference of +2.67 points (95% CI, 1.87 to 3.47).
  • Immediate Post- to 2-Month Post-training: Scores declined to 7.78 (intermediate), a difference of −0.93 points (95% CI, −1.63 to −0.24).
  • 2-Month to 4-Month Post-training: Following retraining, scores increased to 8.05 (advanced), a difference of +0.20 points (95% CI, −0.59 to 0.99).
  • Overall Retention: From immediate post-training to 4-months post-training, the mean score difference was −0.61 points (95% CI, −1.17 to −0.06), indicating that while some decay occurred, the 4-month score remained in the "advanced" competency range.
• Subgroup Analysis:
  • Intermediate Pre-training Group: This group showed the most distinct benefit from the retraining. They advanced immediately post-training, regressed to intermediate at 2 months, and successfully returned to the advanced level at 4 months.
  • Beginner Pre-training Group: This group advanced immediately but regressed to intermediate at 2 months and failed to return to the advanced level by 4 months.
  • Advanced Pre-training Group: This group maintained advanced competency across all assessments, showing minimal fluctuation.
• Reliability: The scoring system demonstrated good interrater reliability (ICC 0.86 for consistency).

Key Contributions

1. Validation of Spaced Practice in Cardiac POCUS: The study provides pilot evidence that a spaced practice curriculum with a single, brief retraining session can mitigate skill decline and support medium-term (4-month) retention of cardiac POCUS image acquisition skills.
2. Differentiation by Competency Level: The research identifies that the efficacy of a single retraining session is not uniform. It suggests that learners with intermediate pre-training competency benefit most from this specific curriculum design, as they are able to recover to advanced levels after a brief interval. Conversely, beginner learners may require additional reinforcement beyond a single retraining session to achieve durable advanced competency, while advanced learners may require more sophisticated instructional content rather than basic image acquisition training.

Significance and Claims
The authors claim that this pilot study addresses a gap in medical education by demonstrating that spaced practice can be effectively applied to cardiac POCUS training to counteract the known phenomenon of skill decay. The study suggests that the "one-size-fits-all" approach to POCUS curricula may be insufficient given the increasing heterogeneity of baseline skills among trainees. Instead, curricula should be tailored to learner competency levels.

The authors explicitly state that their findings are modest and preliminary. They acknowledge limitations, including the lack of a control group (though based on existing literature regarding skill decay), the use of a single instructor, and the assessment of skills on a single healthy volunteer rather than diverse patient populations. Consequently, the paper concludes that while the spaced practice model shows promise, larger cohort studies with longer follow-up periods (at least one year) are necessary to confirm these findings and determine the optimal retraining strategy for durable skill retention.