Cardiac Point-of-Care Ultrasound (POCUS): Extending the Reach

This issue of JASE features a new ASE Guidelines and Standards document, Recommendations for Cardiac Point-of-Care Ultrasound in Children: A Report from the American Society of Echocardiography.1Lu J.C. Riley A. Conlon T. et al.Recommendations for cardiac point of care ultrasound (POCUS) in children: a report from the American Society of Echocardiography.J Am Soc Echocardiogr. 2023; 36: 265-277Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar This document is the result of a unique collaboration of experts from pediatric departments of cardiology, critical care medicine, emergency medicine, and anesthesiology. Whereas cardiac POCUS has become a required skill in adult emergency medicine and critical care training programs, similar standardization of training in pediatric non-cardiology specialties has not been established. This document helps fill that gap. The document provides instructions regarding imaging views and equipment, indications appropriate to a pediatric population, and recommendations for reporting and quality assurance. ASE has previously published guidelines for adult echocardiography laboratories for training of users of POCUS.2Kirkpatrick J.N. Grimm R. Johri A.M. 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.J Am Soc Echocardiogr. 2020; 33: 409-422.e4Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar Relevant to the aforementioned guidelines document and also published in this issue are the results of a survey from the American Society of Echocardiography Task Force on Cardiac POCUS in Children.3Conlon T. Levine J.C. Miller-Hance W.C. et al.The role of the pediatric echocardiography laboratory in supporting point-of-care ultrasound (POCUS) initiatives: a survey from the American Society of Echocardiography task force on cardiac POCUS in children.J Am Soc Echocardiogr. 2023; : 333-335Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar This survey of North American pediatric echo lab directors was conducted to understand perceptions and challenges related to clinical use of cardiac POCUS in children. Challenges identified were related to collaboration between pediatric echo labs and others providing cardiac POCUS in children, and difficulties in defining and measuring competency of providers. New applications of POCUS continue to receive coverage in JASE. In the current issue, Istrail et al. present a novel method of noninvasive estimation of right atrial pressure using POCUS.4Istrail L. Kieman J. Stepanova M. A novel method for estimating right atrial pressure with point of care ultrasound.J Am Soc Echocardiogr. 2023; : 278-283Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Right atrial depth was measured from the parasternal long axis view as the depth of the non-coronary aortic valve cusp attachment to the posterior left ventricular outflow tract. Added to this with the patient at a 45-degree angle, was the vertical distance from the sternum to the meniscus of the column of blood in the internal jugular vein. The method was validated by correlation with right heart catheterization and is worthy of consideration for bedside assessment of volume status, especially when the physical exam is difficult. Important uses of POCUS that the Journal has previously highlighted include detection of disease when comprehensive Doppler echocardiography may not be immediately available or as an extension of the physical examination. A few recent studies have assessed POCUS for detection of valvular heart disease. In one of these, imaging was performed by physicians with level 3 competency in echocardiography using pocket size devices with grayscale and color Doppler and compared with results of a standard transthoracic examination.5Kikoïne J. Hauguel-Moreau M. Herguault H. et al.Screening of native valvular heart disease using a pocket-sized transthoracic echocardiographic device.J Am Soc Echocardiogr. 2022; 35: 196-202Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar The pocket size device was sensitive and specific for the detection of valvular disease and had good agreement with results of the standard transthoracic examination. In a small study of patients with severe tricuspid regurgitation (TR), pocket size ultrasound with color Doppler was performed by cardiology fellows with at least 4 weeks of formal training in echocardiography and applied as an extension of the physical examination.6Bohra C. Khachadourian V. Vogel B. et al.Comparison of hand-held ultrasound assisted physical examination to physical examination alone in detecting isolated severe tricuspid regurgitation.J Am Soc Echocardiogr. 2022; 35: 525-527Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar Detection of severe TR, classically challenging by auscultation alone because of the lower pressures in the right heart, was often missed by physical examination. However, ultrasound assisted physical examination approximately tripled the sensitivity for detection of severe TR. Among patients with known or suspected aortic stenosis, a novel hand-held tablet device equipped with a 2- to 5-MHz phased array transducer with continuous wave (CW) Doppler capability was used to record the highest velocity through the aortic valve; findings were compared with those obtained with a full-size system.7Sachpekidis V. Papadoupoulou S.-L. Kantartziu V. et al.A novel handheld echocardiography device with continuous wave Doppler capability: implications for the evaluation of aortic stenosis severity.J Am Soc Echocardiogr. 2022; 35: 1273-1280Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar All imaging was performed by the same expert cardiologist. Feasibility of diagnostic CW Doppler signal using the hand-held device was 97.5%, and there was excellent agreement between the maximal velocity measurement with the tablet device and the standard ultrasound system when the apical 5 chamber view was used for both. A comprehensive Doppler echocardiographic study would still be desired in follow-up of symptomatic patients or those with suspected moderate or greater degrees of valve disease, with mild aortic stenosis followed at a later time. However, in each of the above studies, the hand-held device was useful for detection of valve disease at the point of care. POCUS also has great promise in regions where echocardiography is not readily available; it might even be applied by nontraditional users. Obstetricians in India were provided hands-on training in image acquisition using a portable ultrasound device and then obtained parasternal long and short axis views and apical 4 chamber views with two-dimensional echocardiography and color Doppler in 301 pregnant and postpartum women.8Alsharqi M. Ismavel V.A. Arnold L. et al.Focused cardiac ultrasound to guide the diagnosis of heart failure in pregnant women in India.J Am Soc Echocardiogr. 2022; 35: 1281-1294Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Obstetricians with experience in obstetric ultrasound imaging required less training and obtained better quality images. Images were deidentified and transferred for remote interpretation by experts. Among the patients, about half suspected to have heart failure, many abnormalities were identified with mitral valve disease the most common pathology. In a subset that underwent complete standard transthoracic echocardiography, agreement of diagnoses was good. The methods employed in this study could be used in low resource settings for screening pregnant or postpartum women who present with cardiac symptoms. The COVID-19 epidemic has resulted in numerous innovations in healthcare practice and delivery. In a new application of POCUS, telehealth physicians guided patients to image their upper chests using POCUS devices and display the findings for physician interpretation and automated detection of ultrasound lung comets.9Kimura B.J. Resnikoff P.A. Tran E.M. et al.Simplified lung ultrasound examination and telehealth feasibility in early SARS-CoV-2 infection.J Am Soc Echocardiogr. 2022; 35: 1047-1054Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Although no patient had prior imaging experience, all were able to perform self-imaging with telehealth physician guidance. Performing cardiovascular ultrasound is no longer the exclusive responsibility of echocardiography laboratories. POCUS devices and new users will extend it is reach. We look forward to further study of interesting advanced applications of POCUS, not only to detect disease but also to improve patient outcomes.