Curr Cardiovasc Imaging Rep (2013) 6:301–304 DOI 10.1007/s12410-013-9214-4

INVITED COMMENTARY

Handheld Echocardiography: Its Role in Intensive Care Units David M. Dudzinski & Michael H. Picard

Published online: 26 May 2013 # Springer Science+Business Media New York 2013

Abstract Hand-held echocardiography (HHE) is being explored for use in the intensive care arena as an extension of the physical examination for real time and iterative information. HHE can help assess chamber size, ventricular function, and presence of fluid collections, and thus is useful in determining etiology of shock and measuring volume status. With additional outcomes and cost-effectiveness research, development of appropriate indications for HHE, and multisociety guidelines on competence assessment and quality control, HHE is expected to be increasingly integrated into intensive care medicine. Keywords Echocardiography . Intensive care unit . Hand held echocardiography

Echocardiography has a prominent world-wide role for the assessment of cardiac pathophysiology. Miniaturization in ultrasonography platforms continues to expand the role of echocardiography in a variety of practice environments [1, 2]. In the last decade, hand-carried cardiac ultrasonography (HCCU) devices the size and weight of laptop computers have entered practice, but these are now being superseded by handheld echocardiography (HHE) devices, similar in size to smartphones. Such devices fit in pockets and can readily be moved from patient to patient without delays in transporting or powering-on the device [3–5]. HHE has been studied in the outpatient clinic, emergency ward, and inpatient floors [6, 7] but the rapid technologic developments have outpaced both D. M. Dudzinski : M. H. Picard Division of Cardiology and Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA M. H. Picard (*) Cardiac Ultrasound Laboratory, Yawkey 5E, Massachusetts General Hospital, 55 Fruit St, Boston, MA 02114, USA e-mail: [email protected]

large experiential and outcome studies as well as formal guidelines. A logical application for the use of HHE is in intensive care units. While the American Society of Echocardiography (ASE) promulgated a 2010 statement on the use of portable focused cardiac ultrasonography in emergency medicine [8], there is not a similar recent document describing HHE or portable echocardiography in intensive care, except for a prescient but now dated 2002 general overview on HCCU [9]. In contrast, HHE seems more accepted in European practice, and the European Association of Echocardiography has authored a 2011 position statement on HHE [3]. Philosophically and technologically, HHE is not a replacement for comprehensive, standard transthoracic echocardiography (sTTE). The major advantage of HHE in critical care is real-time interpretation by the treating physician, and as such, most consider HHE not an advanced imaging modality, but rather an extension of the physical examination [2, 3, 9, 10]. For the critically ill patient, the physical examination may be limited by positive pressure ventilation, incisions, and body habitus; HHE, though affected by similar factors, may increase sensitivity of bedside examination [11]. However, users of HHE must accept that expediency justifies potentially sacrificing some information and diagnostic accuracy from sTTE [9, 12, 13]. The HHE imaging protocol – in exact analogy to a physical examination – should be tailored by the operator to answer specific bedside questions (e.g., “goal-directed”) [1, 11, 14, 15]. Also akin to physical examination, HHE facilitates repeated iterative examinations that can serially follow physiologic parameters in real time. While HCCU systems have some advanced functionalities of sTTE machines, present capabilities of HHE devices include two-dimensional gray scale imaging (with limited sector angle and depth) and color modalities. HHE typically does not include Doppler or advanced measurement capabilities. Accordingly, HHE will be primarily applicable to assessments of global ventricular function, chamber size and inferior vena cava (IVC) caliber, and extracardiac fluid

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collections. It is also plausible that HHE platforms will be applicable to abdominal and lung ultrasonography [16]. &

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Ventricle Systolic Function: Imaging of ventricular systolic function provides insight into mechanisms of unexplained shock (e.g., cardiogenic versus hypovolemic, septic, tamponade, pulmonary embolus), excludes occult cardiomyopathy, and helps design and titrate rational inotrope and vasopressor strategies. Experience with noncardiologist users suggests reasonable overall accuracy (~80%) in subjectively identifying abnormal versus normal left ventricle function, but there is still wide disparity in ejection fraction estimation and a tendency to overestimate systolic function across the spectrum of mild to severe ventricular dysfunction [17, 18]. Even in populations with predominantly normal left ventricle function, this disparity in ejection fraction assessment exists [18]. Right Ventricle: HHE assessment of acute cor pulmonale is an important branchpoint in the assessment of shock phenotypes particularly to exclude right ventricular strain from either pulmonary embolus or right ventricle myocardial infarction. In addition to findings of acute dilatation and right ventricle hypokinesis, HHE may provide insight into both right ventricle volume and pressure overload states by attention to the geometry of the ventricular septum. Other useful measures in assessing for pulmonary embolus include ratio of diastolic diameters of right ventricle versus left ventricle, visualization of thrombus-in-transit, IVC caliber, and severity of tricuspid regurgitation. Additionally, there may be prognostic information especially as regards right ventricular dysfunction in sepsis, pulmonary embolism, and adult respiratory distress syndrome [11]. Volume Status: A broad literature correlates IVC diameter and collapsibility to right atrial pressures and indirectly to pulmonary wedge pressures [5, 19]. HHE thus complements bedside clinical assessment of neck veins [20]. HHE has the potential to add further detail and stratification ability to that provided by biomarkers, which typically provide binary information about the presence or absence of volume overload but do not differentiate if right, left or both ventricles are involved. In patients admitted

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with acute heart failure, HHE assessment of maximum IVC size and compressibility (taken at both admission and discharge) correlated with 30 day readmission for heart failure [21]. Serial IVC assessments could direct proper intensity of diuretic therapy and corroborate the clinical judgment regarding appropriate timing of transition from intravenous to oral diuretics and readiness for discharge. Collateral findings indicative of extra-lung water, including ultrasound lung comets (representing edematous interlobular septa) may be similarly useful in HHE-based follow-up of the heart failure patient [22]. Fluid Collections: HHE readily visualizes pericardial effusions and can assess for tamponade when considering shock etiologies in the scenario of preserved left ventricular function and clear lungs. Chamber inversion should be identifiable on HHE, but with a sensitivity and specificity that like standard echocardiography is dependent on acquisition and interpretation skill.

HHE can readily integrate into the workflow of intensive care units (ICU) at multiple junctures (Table 1). HHE, perhaps as a part of a broader “head-to-toe” screening ultrasound performed upon ICU admission, has the potential to help revise and confirm suspected admitting diagnoses, prioritize subsequent advanced imaging and invasive testing modalities, and refine the therapeutic plan [23–25]. Groups in Britain are formalizing protocols for ICU screening echocardiography encompassing the elements above [26] and which could ultimately be extended to HHE. Although HHE seems poised to become a major tool in management of critically ill patients, concerns on quality assurance, operator training, and documentation must be addressed as the technology diffuses from the confines of accredited echocardiography laboratories [2]. Overall experience and quality in the interpretation of echocardiography seems to be the primary factor [7]. However, the challenges in formulating recommendations for training and quality assurance are that multiple specialties, practitioner levels, and practice areas are involved, and that the optimal training duration and intensity are unknown. ASE previously advocated a level I certification in echocardiography as a minimum level for HHE performance [9], but all users must learn

Table 1 Points of deployment of HHE in the ICU workflow • Screening examination on ICU arrival (volume status, ventricular dysfunction, and assessment of etiologies of shock or dyspnea) • Extension of initial and serial physical examinations (volume status, ventricular function) • Morning “vital signs” and daily rounds (volume status, ventricular function) • Procedural guidance and post-procedural monitoring (line and lead placements, pericardial effusion) • Screening before and during major therapeutic changes (weaning of diuretics, weaning of inotropes, and mechanical ventricular support) • Urgent assessment of the hemodynamically unstable patient and those in cardiac arrest (identify reversible etiologies; ultrasound scanning during pulse checks in life support protocols [35, 36]) • Screening on discharge/transfer from ICU (e.g., check IVC in heart failure patients)

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echocardiographic anatomy [4], have studied a breadth of pathoanatomic variations, and comprehend the limitations and capabilities of HHE [8]. Protocols aimed at very selected imaging indications have used training durations of as little as 6 to 8 hours [17, 27] with variable results when the concordance of non-experienced users’ findings is compared to experts. Recognizing the need for training by professional echocardiographers, the ASE in 2012 sponsored a full day course on HHE to focus on evaluation of volume status, ventricular function, effusions, and pulmonary edema [28], but more leadership by professional societies is necessary. Non-cardiologist groups have promoted cardiac ultrasound training in critical care, such as the Focused Intensive Care Echo accreditation co-sponsored by the Intensive Care Society and British Society of Echocardiography, and critical care echocardiography by the Critical Care NetWork of the American College of Physicians, but neither has specifically discussed HHE [29, 30]. The integration of HHE into critical care is just beginning, and many other groups are actively working on the focused echocardiographic examination in the critical care setting [31–34]. Further research is needed to define specialty-specific training programs to ensure competence of non-cardiologist users. Training models could be extrapolated from training programs of conscious sedation, fluoroscopy, or advanced cardiac life support, where users are locally credentialed based on a performance evaluation that is specified by government or professional society legislation. Simulation-based education will likely be an important part of training and accreditation for HHE users. As part of training, a commitment to documentation and quality assurance is essential. Ideally the HHE users of each institution or practice would engage in periodic, formal reviews of the quality of imaging and interpretation, supplemented by cross-modality comparison (e.g., results of sTTE, transesophageal echo, computed tomography scans, or invasive hemodynamics) [34]. HHE can elucidate valuable real-time, non-invasive insights into cardiopulmonary physiology of critically ill patients, functioning as an extension of the bedside physical examination [12]. With additional outcomes and costeffectiveness research, development of appropriate indications for HHE, and multisociety guidelines on competence assessment and quality control, HHE is expected to be increasingly integrated into intensive care medicine [1].

Compliance with Ethics Guidelines Conflict of Interest David M. Dudzinski declares no potential conflict of interest. Michael H. Picard declares no potential conflict of interest.

Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors.

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References 1. Moore CL, Copel JA. Point-of-Care Ultrasonography. N Engl J Med. 2011;364:749–57. 2. Marwick TH. The Future of Echocardiography. Eur J Echocardiogr. 2009;10:594–601. 3. Sicari R, Galdersi, Voigt J-U, Habib G, Zamorano JL, Lancellotti P, et al. The Use of Pocket-size Imaging Devices: A Position Statement of the European Association of Echocardiography. Eur J Echocardiogr. 2011;12:85–7. 4. Mondillo S, Giannotti G, Innelli P, Carlo Ballo P, Galderisi M. Hand-held echocardiography: Its Use and Usefulness. Intl J Cardiol. 2006;111:1–5. 5. Goonewardena SN, Spencer KT. Handcarried Echocardiography to Assess Hemodynamics in Acute Decompensated Heart Failure. Curr Heart Fail Rep. 2010;7:219–27. 6. Cardim N, Fernandez Golfin C, Ferreira D, Aubele A, Toste J, Cobos MA, et al. Usefulness of a New Miniaturized Echocardiographic System in Outpatient Cardiology Consultations as an Extension of the Physical Examination. J Am Soc Echocardiogr. 2011;24:117–24. 7. Prinz C, Voigt J-U. Diagnostic Accuracy of a Hand-Held Ultrasound Scanner in Routine Patients Referred for Echocardiography. J Am Soc Echocardiogr. 2011;24:111–6. 8. Labovitz AJ, Noble VE, Bierig M, Goldstein SA, Jones R, Kort S, et al. Focused Cardiac Ultrasound in the Emergent Setting: A Consensus Statement of the American Society of Echocardiography and American College of Emergency Physicians. J Am Soc Echocardiogr. 2010;23:1225–30. 9. Seward JB, Douglas PS, Erbel R, Kerber E, Kronzon I, Rakowski H, et al. Hand-Carried Cardiac Ultrasound (HCU) Device: Recommendations Regarding New Technology. A Report from the Echocardiography Task Force on New Technology of the Nomenclature and Standards Committee of the American Society of Echocardiography. J Am Soc Echocardiogr. 2002;15:369–73. 10. Beaulieu Y. Bedside Echocardiography in the Assessment of the Critically Ill. Crit Care Med. 2007;35(Suppl):S235–49. 11. Salem R, Vallee F, Rusca M, Mebazaa A. Hemodynamic Monitoring by Echocardiography in the ICU: The Role of New Echo Techniques. Curr Opin Crit Care. 2008;14:561–8. 12. Spencer KT. Hand-Carried Cardiac Ultrasound. Curr Cardiovasc Imaging Rep. 2008;1:66–71. 13. Vignon P, Frank MJB, Lesage J, Mücke F, François B, Normand S, et al. Hand-held Echocardiography with Doppler Capability for the Assessment of Critically-ill Patients: Is it Reliable? Intensive Care Med. 2004;30:718–23. 14. Schmidt GA, Koenig S, Mayo PH. Shock: Ultrasound to Guide Diagnosis and Therapy. Chest. 2012;142:1042–8. 15. Garcia KM, Perese S. Can a Handheld Handle Vascular? Contemplation of the Vascular System in Miniature. J Am Soc Echocardiogr. 2012;25:18A. 16. Via G, Storti E, Gulati G, Neri L, Mojoli F, Braschi A. Lung Ultrasound in the ICU: From Diagnostic Instrument to Respiratory Monitoring Tool. Minerva Anestesiol. 2012;78:1282–96. 17. Melamed R, Sprenkle MD, Ulstad VK, Herzog CA, Leatherman JW. Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography. Chest. 2009;135:1416–20. 18. Mark DG, Hayden GE, Ky B, Paszczuk A, Pugh M, Matthews S, et al. Hand-carried Echocardiography for Assessment of Left Ventricular Filling and Ejection Fraction in the Surgical Intensive Care Unit. J Crit Care. 2009;24:470.e1–7. 19. Drazner MH. Is the Inferior Vena Cava Really Superior? JACC Cardiovasc Imaging. 2013;6:29–30. 20. Brennan JM, Blair JE, Goonewardena S, Ronan A, Shah D, Vasaiwala S, et al. Reappraisal of the Use of Inferior Vena Cava

304

21.

22.

23.

24.

25.

26.

27.

Curr Cardiovasc Imaging Rep (2013) 6:301–304 for Estimating Right Atrial Pressure. J Am Soc Echocardiogr. 2007;20:857–61. Goonewardena SN, Gemignani A, Ronan A, Vasaiwala S, Blair J, Brennan JM, et al. Comparison of Hand-Carried Ultrasound Assessment of the Inferior Vena Cava and N-Terminal ProBrain Natriuretic Peptide for Predicting Readmission After Hospitalization for Acute Decompensated Heart Failure. JACC Cardiovasc Imaging. 2008;1:595–601. Bedetti G, Gargani L, Corbisiero A, Frassi F, Poggianti E, Mottola G. Evaluation of Ultrasound Lung Comets by Handheld Echocardiography. Cardiovasc Ultrasound. 2006;4:34–8. Manno E, Navarra M, Faccio L, Motevallian M, Bertolaccini L, Mfochive A, et al. Deep Impact of Ultrasound in the Intensive Care Unit: The “ICU-Sound” Protocol. Anesthesiology. 2012; 117:801–9. Fedson S, Neithardt G, Thomas P, Lickerman A, Radzienda M, DeCara JM, et al. Unsuspected Clinically Important Findings Detected with a Small Portable Ultrasound Device in Patients Admitted to a General Medicine Service. J Am Soc Echocardiogr. 2003;16:901–5. Manasia AR, Nagaraj HM, Kodali RB, Croft LB, Oropello JM, Kohli-Seth R, et al. Feasibility and Potential Clinical Utility of Goal-Directed Transthoracic Echocardiography Performed by Noncardiologist Intensivists Using a Small Hand-Carried Device (SonoHeart) in Critically Ill Patients. J Cardiothorac Vasc Anesth. 2005;19:155–9. Valve Study Group, “Certification in Screening Echocardiography”, available at http://www.researchechocardiography.com/itu_screen ing.html Vignon P, Dugard A, Abraham J, Belcour D, Gondran G, Pepino F, et al. Focused Training for Goal-Oriented Handheld Echocardiography Performed by Noncardiologist

28. 29.

30.

31.

32.

33. 34.

35.

36.

Residents in the Intensive Care Unit. Intensive Care Med. 2007;33:1795–9. Pellikka PA. Echocardiography Here, There, and Everywhere. J Am Soc Echocardiogr. 2012;25:13A. Intensive Care Society. Focused Intensive Care Echo, available at http://www.ics.ac.uk/meetings_seminars/ics_modules/ fice_accreditation Mayo PH, Beaulieu Y, Doelken P, Feller-Kopman D, Harrod C, Kaplan A, et al. American College of Chest Physicians/La Société de Réanimation de Langue Française Statement on Competence in Critical Care Ultrasonography. Chest. 2009;135:1050–60. Marum S, Price S. The Use of Echocardiography in the Critically Ill; The Role of FADE (Fast Assessment Diagnostic Echocardiography) Training. Curr Cardiol Rev. 2011;7:197–200. Gunst M, Ghaemmaghami V, Sperry J, Robinson M, O’Keeffe T, Friese R, et al. Accuracy of Cardiac Function and Volume Status Estimates Using the Bedside Echocardiographic Assessment in Trauma/Critical Care. J Trauma. 2008;65:509–16. Mayo PH. Training in critical care echocardiography. Annals of Intensive Care. 2011;1:36. Price S, Via G, Sloth E, Guarracino F, Breitkreutz R, Catena E, et al. Echocardiography Practice, Training and Accreditation in the Intensive care: Document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS). Cardiovasc Ultrasound. 2008;6:49. Breitkreutz B, Walcher F, Seeger FH. Focused Echocardiographic Evaluation in Resuscitation Management: Concept of an Advanced Life Support-Conformed Algorithm. Crit Care Med. 2007;35(Suppl):S150–61. Breitkreutz B, Price S, Steiger HV, Seeger FH, Ilper H, Ackermann H, et al. Focused Echocardiographic Evaluation in Life Support and Peri-resuscitation of Emergency Patients: A Prospective Trial. Resuscitation. 2010;81:1527–33.