Troubleshooting FoCUS Image Acquisition: Patient Positioning, Transducer Manipulation, and Image Optimization

Published: March 03, 2023

doi:

Adam L. Gottula^2,3, Suhas Devangam, Jessica L. Koehler, Matthew J. Sigakis

¹Department of Anesthesiology, Division of Critical Care,University of Michigan, Ann Arbor, ²Department of Emergency Medicine,University of Michigan, Ann Arbor, ³Max Harry Weil Institute for Critical Care Research and Innovation,University of Michigan, Ann Arbor

Summary

Here, we present a protocol to allow providers to perform focused cardiac ultrasound (FoCUS) in the clinical environment. We describe methods of transducer manipulation, review common pitfalls of transducer movements, and suggest tips to optimize phased array transducer use.

Abstract

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography to add real-time information to patient care. These bedside exams are problem oriented, rapidly and repeatedly performed, and largely qualitative in nature. Competency in FoCUS includes mastery of the stereotactic and psychomotor skills required for transducer manipulation and image acquisition. Competency also requires the ability to optimize the setup, troubleshoot image acquisition, and understand the sonographic limitations because of complex clinical environments and patient pathology. This article presents concepts for successful, high-quality two-dimensional (B-mode) image acquisition in FoCUS.

Concepts of high-quality image acquisition can be applied to all established sonographic windows of the FoCUS exam: the parasternal long-axis (PLAX), parasternal short-axis (PSAX), apical four chamber (A4C), subcostal fourchamber (SC4C), and the inferior vena cava (IVC). The apical five-chamber (A5C) and subcostal short-axis (SCSA) views are mentioned, but are not discussed in-depth. A pragmatic figure illustrating the movements of the phased array transducer is also provided to serve as a cognitive aid during FoCUS image acquisition.

Introduction

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography that provides immediate anatomic, physiologic, and functional information to patient care. These exams, consisting of five classic views, are problem oriented, performed in real time at the bedside, and do not replace comprehensive echocardiography exams¹^,². Given the focused nature of these exams, they are often repeatedly performed when clinical status changes or serial monitoring is required. It is important to have standardized training and obtain adequate images of all five views, when possible, as some views may provide limited information depending on the individual patient and pathology.

The use of FoCUS is rapidly expanding. Many clinical landscapes, such as perioperative anesthesiology, critical care and emergency medicine¹^,²^,³, now routinely employ FoCUS. Inpatient medical wards and outpatient clinical care settings are also adopting this tool to enhance clinical practice⁴^,⁵^,⁶. As a result, several societal bodies, such as the American Society of Echocardiography, the Society of Critical Care Medicine, and the American College of Emergency Physicians, have published guidelines and recommendations for FoCUS competency and scope of practice⁷^,⁸^,⁹. While these guidelines and recommendations are not codified, much of the content is consistent and influences FoCUS training curricula¹⁰.

Beyond didactics and image interpretation, competency in FoCUS includes mastery of stereotactic and psychomotor skill sets. Stereotactic skill refers to the accurate positioning of ultrasound transducers on the body, based on three-dimensional anatomic features. Psychomotor skill describes the relationship between cognitive function and physical movement that influences coordination, dexterity, and manipulation. Expanding knowledge and awareness about these skills supports FoCUS trainee development.

This article presents concepts for high-quality image acquisition in FoCUS, with both pragmatic considerations and attention to stereotactic and psychomotor skill sets. Specifically, it discusses optimal patient positioning, transducer manipulation, and suggests tips to optimize phased array transducer use. Finally, it examines image optimization for 2-dimensional (B-mode or 2-D mode) and motion modes (M-mode).

Protocol

This material is the authors' original work, which has not been previously published elsewhere. The protocol described is for clinical use and not research purposes. De-identified images were obtained from a volunteer model in a non-clinical environment. The authors did not seek a formal "Not Regulated" determination from the IRB in accordance with institutional policy, as the activity falls outside of the Common Rule and FDA definitions of human subject research. 1. The tran…

Representative Results

Representative images obtained from the focused cardiac ultrasound protocol presented above are presented in Figure 2, Figure 3, Figure 4, Figure 5, and Figure 6, demonstrating the feasibility of the technique described. These images were captured with the phased array 5-1 MHz transducer. The parasternal long axis (PLAX) image obtained from protocol se…

Discussion

The aim of this publication is to provide practical recommendations and best practices to achieve optimal FoCUS images in challenging clinical environments. Formal ultrasound seminars, clinical experience, and observations of learners during hands-on teaching have given insight into pitfalls and less optimal tendencies. As a result, many factors that influence the stereotactic and psychomotor skills have become apparent. Although this material is described in relation to FoCUS exams, many of the principles can be applied…

Divulgazioni

The authors have nothing to disclose.

Acknowledgements

We would like to thank the University of Michigan Department of Anesthesia, Max Harry Weil Institute for Critical Care Research and Innovation, and Katelyn Murphy for their administrative and graphic design support.

Materials

Aquasonic ultrasound gel	Parker	30592052	https://dr.graphiccontrols.com/en/catalog/ultrasound-gel/parker-laboratories-01-50-aquasonic-100-gel-5l-1332e66e/
Philips Sparq ultrasound machine	Phillips		https://www.usa.philips.com/healthcare/product/HC795090CC/sparq-ultrasound-system#documents

Riferimenti

Birch, M. S., Marin, J. R., Liu, R. B., Hall, J., Hall, M. K. Trends in diagnostic point-of-care ultrasonography reimbursement for medicare beneficiaries among the US emergency medicine workforce, 2012 to 2016. Annals of Emergency Medicine. 76 (5), 609-614 (2020).
Moore, C. L., Copel, J. A. Point-of-care ultrasonography. The New England Journal of Medicine. 364 (8), 749-757 (2011).
Su, E., Dalesio, N., Pustavoitau, A. Point-of-care ultrasound in pediatric anesthesiology and critical care medicine. Canadian Journal of Anaesthesiology. 65 (4), 485-498 (2008).
Niblock, F., Byun, H., Jabbarpour, Y. Point-of-care ultrasound use by primary care physicians. The Journal of the American Board of Family Medicine. 34 (4), 859-860 (2021).
Coritsidis, G. N., et al. Point-of-care ultrasound for assessing arteriovenous fistula maturity in outpatient hemodialysis. The Journal of Vascular Access. 21 (6), 923-930 (2020).
Gundersen, G. H., et al. Adding point of care ultrasound to assess volume status in heart failure patients in a nurse-led outpatient clinic. A randomised study. Heart. 102 (1), 29-34 (2016).
Kirkpatrick, J. N., et al. Recommendations for echocardiography laboratories participating in cardiac point of care cardiac ultrasound (POCUS) and critical care echocardiography training: report from the American Society of Echocardiography. Journal of the American Society of Echocardiography. 33 (4), 409-422 (2020).
Annals of Emergency Medicine. Ultrasound Guidelines: Emergency, point-of-care and clinical ultrasound guidelines in medicine. Annals of Emergency Medicine. 69 (5), 27-54 (2017).
Levitov, A., et al. Guidelines for the appropriate use of bedside general and cardiac ultrasonography in the evaluation of critically ill patients-part II: cardiac ultrasonography. Critical Care Medicine. 44 (6), 1206-1227 (2016).
Neskovic, A. N., et al. Focus cardiac ultrasound core curriculum and core syllabus of the European Association of Cardiovascular Imaging. European Heart Journal. Cardiovascular Imaging. 19 (5), 475-481 (2018).
Mitchell, C., et al. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. Journal of the American Society of Echocardiography. 32 (1), 1-64 (2019).
Dinh, V. A., et al. Measuring cardiac index with a focused cardiac ultrasound examination in the ED. The American Journal of Emergency Medicine. 30 (9), 1845-1851 (2012).
Expert Round Table on Echocardiography in ICU. International consensus statement on training standards for advanced critical care echocardiography. Intensive Care Medicine. 40 (5), 654-666 (2014).
Expert Round Table on Echocardiography in ICU. International expert statement on training standards for critical care ultrasonography. Intensive Care Medicine. 37 (7), 1077-1083 (2011).
Spencer, K. T., et al. Focused cardiac ultrasound: recommendations from the American Society of Echocardiography. Journal of the American Society of Echocardiography. 26 (6), 567-581 (2013).
Nelson, B. P., Sanghvi, A. Point-of-care cardiac ultrasound: feasibility of performance by noncardiologists. Global Heart. 8 (4), 293-297 (2013).

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Citazione di questo articolo

Gottula, A. L., Devangam, S., Koehler, J. L., Sigakis, M. J. Troubleshooting FoCUS Image Acquisition: Patient Positioning, Transducer Manipulation, and Image Optimization. J. Vis. Exp. (193), e64547, doi:10.3791/64547 (2023).