Abstract
Purpose
Point-of-care ultrasound (POCUS) is highly utilized in the critical care setting. There is also growing evidence supporting use of POCUS by internal medicine (IM) physicians as an extension of traditional physical diagnostic skills. As part of the newly formed curriculum at our residency program, we performed pre and post curriculum assessment of the residents’ ability to acquire focused cardiac, lung, pleural, abdominal and vascular images.
Methods
The POCUS instruction was delivered as a combination of pre-workshop self-study learning materials (monthly textbook chapters, online modules etc.), with short didactic sessions, and hands-on-scanning of healthy, male volunteers at 10-week intervals.
Results
A total of 62 residents (23 Post-Graduate Year 1 (PGY), 24 PGY2, 15 PGY3) participated in the year-long curriculum. When pretest and post test data were analyzed at the end of the curriculum, we calculated the odds ratio for acquiring the correct image (score of 1) vs partial/incorrect acquisition (scores of 2 and 3). Significant differences were found in acquisition of most views including para-sternal short (OR 7.7, 95% CI 2.86–20.74, p < 0.001), Inferior vena cava (IVC) (OR 5.05, 95% CI 1.91–13.35, p = 0.001) and bladder (OR 5.06, 95% CI 1.76–14.55, p = 0.003). Non-significant differences were found in acquisition of apical 4 chamber, pl (A-Line) and internal jugular vein (IJV).
Conclusion
We found that the implementation of a longitudinal POCUS curriculum resulted in significant improvement in image acquisition for many common bedside ultrasound views. Future directions include advancing our bedside echocardiography curriculum for upper-level residents to include quantitative left ventricular and right ventricular function analysis, and including more case based pathologic image review.
Keywords: Point-of-care ultrasound, Internal medicine residents, Graduate medical education, Ultrasound curriculum
Background
The use of point-of-care ultrasound (POCUS) has greatly expanded in recent years beyond its use by physicians in emergency medicine, obstetrics, and intensive care. POCUS competency milestone assessments exist for emergency medicine programs, [1, 2] and it is increasingly utilized in medical subspecialties like rheumatology, nephrology, physical medicine and rehabilitation [3–5].
As procedural and diagnostic POCUS become more widely utilized, an increasing body of evidence to support its use in general internal medicine as an extension of traditional physical diagnostic skills now exists [6–9]. While some data exist about increasing residents’ interest in POCUS training, [10] POCUS training has not taken a significant hold in the educational curriculum of internal medicine residencies across the country. However, the ability to develop a sustainable POCUS curriculum in an internal medicine training program, while remaining minimally invasive to other clinical duties, is becoming more and more important for the field. Despite this growing desire for formal POCUS training, POCUS skills and competence assessments are not yet widely considered milestones in internal medicine residency programs in the United States.
Given this obvious need for assessment, its evolving bedside diagnostic application, and the increasing availability of ultrasound machines (handheld ultrasound devices included), we decided to implement a longitudinal and integrated POCUS curriculum for our internal medicine residents. The focus of the curriculum was to teach basic bedside ultrasonographic image acquisition and how it is utilized and applied to patient care in clinical internal medicine.
Our evaluation of the curriculum consisted of a pre-curriculum assessment of the residents’ ability to acquire focused cardiac (defined by parasternal long/short axis, inferior vena cava, and apical four chamber views), pleural, abdominal and vascular images. A post-curriculum assessment was done at the end of the academic year which tested their ability to acquire said images after a year of training.
Methods
The POCUS instruction was delivered as a combination of pre-workshop self-study learning materials (textbook chapters, online modules etc.), short didactic sessions, and hands-on-scanning of healthy, male volunteers. The didactic and hands-on learning sessions were delivered by experienced critical care faculty, internal medicine faculty, critical care fellows, and chief residents. These sessions would entail 2 faculty teachers to 62 internal medicine residents, giving a teacher to learner ratio of 1:31. The sessions took place at 10-week intervals throughout the academic year with a total of 5 sessions, each focusing on a different exam. Baseline data regarding specialty choice was obtained if the student was interested in cardiology, or critical care medicine (2 ultrasound heavy fields). This cohort made up 14/62 residents present within the study.
Data collection
The residents’ image acquisition skills were assessed prior to initiation of the curriculum and at the end of the academic year. At both intervals, the residents were asked to acquire the 3 basic cardiac views (parasternal long and short, and apical four chamber), inferior vena cava, pleural artifacts (lung sliding and A-lines), kidney (long axis and short axis), bladder and internal jugular vein.
Definitions and outcomes
The residents were given a score of 1 for correct acquisition, 2 for an incomplete view, and 3 for complete inability to acquire the image. Scores of 2 and 3 were considered “incorrect views”. All the acquired images were scored using predetermined grading rubrics. The rubric for cardiac images (Parasternal short axis, parasternal long-axis, apical 4 chamber view, IVC) were attained from the standardized transthoracic echocardiograph guidelines as illustrated by the American society of echocardiography [17]. Rubrics for other views were developed by critical-care staff within the hospital. Both the pre and post curriculum image assessments were graded by internal medicine and critical care staff with experience in utilization and education of POCUS.
Statistical analysis
Using generalized mixed linear modeling (GLMM) clustering on subject and McNemar’s test, we calculated individual pre-curriculum and post-curriculum average for all views as well as the cumulative average for each view for first year, second year, and third year residents (R1, R2, R3 respectively). We then calculated odds ratios comparing pre-curriculum vs post-curriculum acquisition of images for each view for each year and for all residents.
Results
A total of 62 residents (23 R1, 24 R2, 15 R3) participated in the year-long curriculum. Significant post-curriculum improvement was demonstrated for the following view: para-sternal short axis (OR 7.7, 95% CI 2.86–20.74, p < 0.001) (Fig. 1), IVC (OR 5.05, 95% CI 1.91–13.35, p = 0.001) (Fig. 1), lung-sliding (OR 27.95, 95% CI 2.85–274.57, p < 0.001) (Fig. 1), kidney long axis (OR 11.02, 95% CI 2.74–44.68, p < 0.001) (Fig. 1) and short axis (OR 7.12, 95% CI 2.60–19.45, p < 0.001), bladder (OR 5.06, 95% CI 1.76–14.55, p = 0.003). A trend towards post-curriculum improvement was demonstrated in the following views but did not meet statistical significance: apical 4 chamber, lung A-lines and internal jugular vein. Raw data of correct view acquisition pre- and post-curriculum can be assessed in Table 1.
Fig. 1.
Correct view obtained pre curriculum and post curriculum; all residents for the 4 shown views. PSS parasternal short axis, IVC Inferior vena cava
Table 1.
Raw data of correct acquisitions in pre- and post-curriculum cohorts
| Total correct acquisitions, pre-curriculum PG1-PGY3 | Total correct acquisitions, post-curriculum PG1-PGY3 | Difference post-curriculum | |
|---|---|---|---|
| Parasternal long axis | 23/62 | 47/62 | + 24/62 |
| Parasternal short axis | 24/62 | 50/62 | + 24/62 |
| Apical four chamber | 11/62 | 30/62 | + 19/62 |
| Inferior vena cava | 16/62 | 35/62 | + 19/62 |
| Lung sliding | 23/62 | 51/62 | + 28/62 |
| Lung A-lines | 24/62 | 49/62 | + 25/62 |
| Kidney long axis | 27/62 | 52/62 | + 25/62 |
| Kidney short axis | 28/62 | 54/62 | + 26/62 |
| Bladder | 32/62 | 51/62 | + 19/62 |
| Internal jugular | 28/62 | 56/62 | + 28/62 |
These cohorts included 23 PGY1, 24 PGY2, and 15 PGY3 residents
Discussion
Based on our findings, we have shown a longitudinal POCUS curriculum for internal medicine residents is feasible and effective for teaching basic image acquisition, while remaining minimally invasive in terms of time constraints for residents. Point of care ultrasound is being used with more frequency for bedside assessments and as an adjunct to the traditional physical exam across many medical specialties. With the increased clinical use, it will be imperative for internal medicine residencies to implement POCUS curricula and deliver them in a longitudinal fashion to all residents. Studies have shown that short training sessions can improve novice learners’ image acquisition skills and confidence with using POCUS [11–14]. While initial instruction and training are important to introduce POCUS skills, continuing education on image acquisition and recognition is paramount to POCUS skill retention of physicians in training [15–17].
Our study has several limitations. The test used at the beginning and at the conclusion of the POCUS curriculum were the same, so recall bias could have affected our results. We did not ask residents if they had prior experience using POCUS prior to the curriculum. Residents with prior experience could have had higher pretest scores that those who had no experience. Our scoring system has not been validated; thus, we cannot say our residents gained competency nor proficiency in POCUS. We are reporting our experience with teaching residents’ basic POCUS image acquisition skills and the improvement in these skills after completing a longitudinal curriculum.
Future directions
The overall goal is to advance the curriculum for the second- and third-year residents after they complete the basic POCUS curriculum their first year. The advanced curriculum would include quantitative assessments of right and left ventricular function, advanced case presentations incorporating pathologic images, and education revolving around established protocols. Ideally, we would like to use standardized patients with pathologic findings, more frequent training sessions, and portable hand-held ultrasound machines for the advanced curriculum. We hope to develop an ultrasound tract where interested residents can obtain and log POCUS images for review by a certified cardiologist or critical care physician. Residents in this tract would also be expected to teach first year residents during the basic POCUS curriculum.
Conclusions
In our study, we found that the implementation of a longitudinal POCUS curriculum is a feasible and effective tool to significantly improve image acquisition skills for many common bedside ultrasound views.
Abbreviations
- POCUS
Point of care ultrasound
- PGY
Post-graduate year
- PSS
Parasternal short axis
- KSX
Kidney short axis
- KLX
Kidney long axis
- IJV
Internal jugular vein
- IVC
Inferior vena cava
- A4C
Apical four chamber
- LS
Lung sliding
- GLMM
Generalized mixed linear modeling
- OR
Odds ratio
- CI
Confidence interval
Authors contributions
All authors contributed to conception of study and design, design of curriculum, acquisition, and analysis of data. Drafting and revision of article.
Funding
There was no internal or external source of funding for this project.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Declarations
Conflict of interest
Authors declare that there is no conflict of interest regarding the publication of this manuscript.
Ethical approval
The study has been approved by the Biomedical IRB01 of the University of Iowa (201708716 IRB Approval #).
Consent to participate
Informed Consent for data collection has been approved by those who participated in the curriculum. Those involved in the curriculum were given the opportunity to opt out from data collection.
Consent For Publication
Not applicable.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.