Via Research Recognition Day Program VCOM-Carolinas 2025

Clinical Educational Research

ULTRASOUND COMPATIBLE TRAINING HARDWARE FOR DETERMINING FETAL CROWN-RUMP LENGTH MEASUREMENT IN UTERO Alyssa McMandon, OMS-III; Haleigh Stein, MS, OMS-III; Michael Benavidez Arias, MA, OMS-III; Austin Ewanick, OMS-II; Anne Guglielmo, OMS-II; Maggie Morehouse, OMS- II; Michael Parks, MPA, NREMT; David Redden, PhD; Tom Lindsey, DO, FACOS, CHSE* Edward Via College of Osteopathic Medicine, Spartanburg, SC Introduction Results Discussion

Background: Crown-Rump Length (CRL) is an essential measurement during prenatal care. 1 CRL is the distance from cranial to caudal ends of the fetus. 2 This measurement helps to estimate gestational age from weeks 6 to 13 due to the variability in fetal size during early pregnancy. 3 Measurement errors can significantly affect the estimated fetal weight leading to flaws in clinical assessment and patient management. 1 Challenge: During the didactic years, medical students often experience obstacles in attaining access to interactions with actual patients. There is not currently a training model to develop the skill required to collect CRL measurements. Rational: Simulation learning can provide hands-on training in a safe, controlled environment. Such a model would facilitate better outcomes when measuring CRL in the clinical setting. Objective: Development of a cost-effective, ultrasound compatible device that accurately simulates measuring CRL in utero to prepare medical students to perform this skill during clinical encounters. Design • Instrument development and cross-sectional validation study Intervention • The CRL trainer was crafted with three layers- one replicating the fetus, another replicating gestational features, and a third layer, compatible with ultrasound imaging, to replicate skin (Fig. 1A). Groups • Forty first- and second-year students at VCOM-CC provided ultrasound measurements for 2 models, 35 mm and 40 mm (Fig. 1B). Statistical Analysis • The difference between the estimated length provided by the student and the true length gave the error. Using the errors, equivalence testing was used, specifically two one-sided tests (TOST), to estimate bounds on the mean error • Type I error rate set at 0.05. Methods

Data Interpretation: • The 35 mm model data provides sufficient evidence to declare that the true mean error rate is within ± 1.5 mm using a Type I error rate of 0.025 for each test. • The 40 mm model data provides sufficient evidence to declare that the true mean error rate is within ± 1.0 mm using a Type I error rate of 0.025 for each test. All graphs and analyses were programmed using SAS 9.4 (Fig. 2). • First- and second-year medical students were accurately able to measure CRL within 1.0 and 1.5 mm (95% confidence interval) for the 40 mm and 35 mm models, respectively. Limitations: • Filling balloon with fetus and water left room for human error with air bubbles • Varying levels of competence with using ultrasound technology Future Studies: • Fetal pathologies • Anatomically accurate pelvic cavity for intravaginal ultrasound use • Wearable device Conclusion: Introduction of an anatomically accurate, ultrasound compatible device to the medical curriculum provides students the opportunity to practice successfully determining CRL to prepare them for the clinical setting. References 1. Gadsbøll, K., Wright, A., Kristensen, S. E., Verfaille, V., Nicolaides, K. H., Wright, D., & Petersen, O. B. (2021). Crown – rump length measurement error: impact on assessment of growth. Ultrasound in Obstetrics and Gynecology, 58(3), 354 – 359. https://doi.org/10.1002/uog.23690 2. Blaas, H. G. K., & Carrera, J. A. M. (2009). Investigation of early pregnancy. Ultrasound in Obstetrics and Gynaecology Book and CD-ROM, 57 – 78. https://doi.org/10.1016/B978-0-444-51829-3.00004-0 3. Jones, J., & Gaillard, F. (2008). Crown rump length. In Radiopaedia.org. Radiopaedia.org. https://doi.org/10.53347/rID-1186 We would like to thank the VCOM Sim Center for their investment in our education and the resources used for our project. Acknowledgements

Standard Deviation of Error (mm)

Sample Mean (mm)

Largest Negative Error (mm)

Largest Positive Error (mm)

Model

Mean Error (mm)

Table 1: Descriptive Statistics for Measurement Error by Model 35 mm 35.345 mm 0.345 mm 3.296 mm -7.5 mm 10.4 mm 40 mm 40.233 mm 0.233 mm 2.293 mm -4.2 mm 6.4 mm 35 mm Model 40 mm Model Null Hypothesis Alternative Hypothesis p-value p-value Abs (mean error) ≥ 3.0 mm Abs (mean error) < 3.0 mm <0.0001 <0.0001 Abs (mean error) ≥ 2.5 mm Abs (mean error) < 2.5 mm <0.0001 <0.0001 Abs (mean error) ≥ 2.0 mm Abs (mean error) < 2.0 mm 0.0015 <0.0001 Abs (mean error) ≥ 1.5 mm Abs (mean error) < 1.5 mm 0.0163 0.0006 Abs (mean error) ≥ 1.0 mm Abs (mean error) < 1.0 mm 0.1082 0.0203

Table 2: Tests for Mean Error

B.

A.

Figure 2: 95% Confidence Interval for Mean Error

Figure 1: Ultrasound Compatible Model

2025 Research Recognition Day

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