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

Diagnostic accuracy of a hand-held ultrasound scanner in routine patients referred for echocardiography

BACKGROUND

The aim of this study was to investigate the imaging capabilities of recent hand-held ultrasound scanners.

METHODS

Three hundred forty-nine patients were scanned with hand-held ultrasound (HAND) and high-end echocardiography (HIGH). Segmental endocardial border delineation was scored (2 = good, 1 = poor, 0 = invisible) to describe image quality. Assessments of left ventricular (LV) dimensions, regional and global LV function, and grades of valve disease were compared.

RESULTS

The mean endocardial visibility grades were 1.6 ± 0.5 with HAND and 1.7 ± 0.4 with HIGH (P < .01). Regional wall motion was scored very similarly (κ = 0.73, P < .01). Ejection fraction assessment (bias = 1.8%, 1.96 × SD = 8.3%) and LV measurements (r = 0.99, P < .01; interventricular septum: bias = 0.91 mm, 1.96 × SD = 2.1 mm; LV end-diastolic diameter: bias = 0.5 mm, 1.96 × SD = 4.1 mm; LV posterior wall: bias = 0.61 mm, 1.96 × SD = 2.4 mm) showed negligible deviations. No pericardial effusion or valve stenosis was missed. Regurgitations missed by HAND were all graded "minimal" on HIGH. Regurgitations were mildly overestimated by HAND. Overall concordance for detection of regurgitations was very good (κ = 0.9, P < .01).

CONCLUSIONS

Handheld echocardiography was feasible and missed no relevant findings. Given the future implementation of spectral Doppler capabilities, this handheld scanner can safely be used in clinical routine.

Improved cardiovascular diagnostic accuracy by pocket size imaging device in non-cardiologic outpatients: the NaUSiCa (Naples Ultrasound Stethoscope in Cardiology) study

Miniaturization has evolved in the creation of a pocket-size imaging device which can be utilized as an ultrasound stethoscope. This study assessed the additional diagnostic power of pocket size device by both experts operators and trainees in comparison with physical examination and its appropriateness of use in comparison with standard echo machine in a non-cardiologic population.

Three hundred four consecutive non cardiologic outpatients underwent a sequential assessment including physical examination, pocket size imaging device and standard Doppler-echo exam. Pocket size device was used by both expert operators and trainees (who received specific training before the beginning of the study). All the operators were requested to give only visual, qualitative insights on specific issues. All standard Doppler-echo exams were performed by expert operators.

One hundred two pocket size device exams were performed by experts and two hundred two by trainees. The time duration of the pocket size device exam was 304 ± 117 sec. Diagnosis of cardiac abnormalities was made in 38.2% of cases by physical examination and in 69.7% of cases by physical examination + pocket size device (additional diagnostic power = 31.5%, p < 0.0001). The overall K between pocket size device and standard Doppler-echo was 0.67 in the pooled population (0.84 by experts and 0.58 by trainees). K was suboptimal for trainees in the eyeball evaluation of ejection fraction, left atrial dilation and right ventricular dilation. Overall sensitivity was 91% and specificity 76%. Sensitivity and specificity were lower in trainees than in experts.

In conclusion, pocket size device showed a relevant additional diagnostic value in comparison with physical examination. Sensitivity and specificity were good in experts and suboptimal in trainees. Specificity was particularly influenced by the level of experience. Training programs are needed for pocket size device users.

Focused Transthoracic Echocardiography in the Perioperative Period

Ultrasound applications in perioperative medicine have expanded enormously over the past decade. Transoesophageal echocardiography has been performed by anaesthetists during cardiac surgery for over 20 years. With the increasing availability of portable ultrasound systems, the use of ultrasound to assist in vascular cannulation and regional anaesthesia has been well described. Portable ultrasound systems come with a range of probes for different applications, including transthoracic echocardiography. While transthoracic echocardiography has traditionally been the domain of cardiologists, its use has been increasing in critical care, the emergency room and, recently, by anaesthetists in the perioperative period. Unlike formal cardiology-based transthoracic echocardiography, focused, goal-directed transthoracic echocardiography is often more appropriate in the perioperative period to address a particular question and can be performed in just a few minutes. Transthoracic echocardiography allows rapid, noninvasive, point-of-care assessment of ventricular function, valvular integrity, volume status and fluid responsiveness. It can help distinguish undifferentiated systolic murmurs preoperatively, give valuable information on the aetiology of unexplained hypotension and cardiovascular collapse and assess response to therapeutic interventions such as vasoactive drugs and volume resuscitation. Focused transthoracic echocardiography should include qualitative assessment of left and right ventricular function, an estimate of aortic valve gradient, right ventricular systolic pressure and intravascular volume status as minimum requirements. Transthoracic echocardiography is a valuable tool in the perioperative period and ideally the equipment and expertise should be available in all operating rooms.

Peri-resuscitation echocardiography: training the novice practitioner

AIMS

Echocardiography performed in an ALS-compliant manner provides a tool whereby some of the potentially reversible causes of cardiac arrest can be diagnosed in real time by minimally trained practitioners. One of the major concerns this raises is how to deliver effective training to the required standard. The objective of this study was to determine the effectiveness of number of different educational methods used teach echocardiography to novices. This involved assessment of cognitive, psychomotor skills and affective aspects in five key areas.

METHODS

The study population was a convenience sample from participants attending standardised structured one-day training courses in peri-resuscitation echocardiography (n=204). Subjects were assessed for five learning outcomes including knowledge and image interpretation, practical performance of echocardiography including time taken to obtain a diagnostic view, integration into the ALS algorithm and overall compliance with established resuscitation guidelines.

RESULTS

There was a significant improvement in knowledge and interpretation of echocardiographic images before and after completion of the one-day course (pre 62%, post 78%, p<0.01). Skills acquisition resulted in 100% of participants being able to obtain a subcostal view of diagnostic quality by the end of the course, and 86% with a mean time to acquisition of <10s. On completion of the training programme, incorporation of echocardiography into current resuscitation practice did not compromise ALS-compliance.

CONCLUSION

Novice echocardiographers can obtain knowledge and skills relevant to ALS-compliant peri-resuscitation echocardiography using a range of educational techniques. In addition to the standard one-day training courses available, continued mentored practice and didactic adherence to ALS algorithms is required.

Focused transthoracic echocardiography

Caring for critically ill patients requires rapid and accurate diagnosis followed by prompt interventions. The physical examination remains an important part of the assessment of such patients, but it has been shown to have a low sensitivity and specificity in judging left ventricular function and intravascular volume. Invasive hemodynamic monitoring has similarly been shown to have significant limitations and has failed to demonstrate a mortality benefit in several recent studies. In some studies, it has been shown to be harmful. Focused transthoracic echocardiography (TTE) has emerged as a noninvasive and portable imaging technique that is capable of providing rapid and accurate information about the heart at the bedside. It can be used to complement the physical examination and result in marked improvement in diagnostic accuracy. Focused TTE can be used as a screening and monitoring tool. Studies have shown that clinicians can be trained to determine left ventricular function, detect pericardial effusions, predict intravenous fluid responsiveness, and identify important valvular defects in a relatively short period. This article describes the indications for focused TTE, provides evidence that clinicians can be rapidly taught the technique, reviews how the focused studies affect management, and discusses the advantages and limitations of this tool.

Hospitalist use of hand-carried ultrasound: preparing for battle

Hand-carried ultrasound (HCU) is a burgeoning technology at a critical point in its development as a general diagnostic technique. Despite the known safety and accuracy of ultrasound in radiology and echocardiography, the use of HCU to augment physical diagnosis by all physicians has yet unrealized potential. In order to incorporate ultrasound into a diagnostic model of routine bedside application, simple imaging and training protocols must first be derived and validated. Simplified cardiac ultrasound exams have already been validated to detect evidence-based targets such as subclinical atherosclerosis, heart failure, and elevated central venous pressures. However, for general examination of the acutely ill patient, it is the internist-hospitalist who should derive a full-body ultrasound examination, balancing training requirements with the numerous clinical applications potentially available. As the hospital's leading diagnostician with ultrasound expertise available in-house, the hospitalist could develop HCU so as to triage and refer more appropriately and limit unnecessary testing and hospital stays. Active involvement by hospitalists now in the planning of outcome, validation, and training studies, will be invaluable in the formation of an "ultrasound-assisted" physical examination in the future and will promote competent, cost-effective applications of HCU within general medical practice.

Echocardiography for the clinician: a practical update

Echocardiography is the mainstay of cardiovascular diagnostics, and is the most performed test for the evaluation of cardiac function. Critical and costly management decisions are based on quantification of left ventricular volumes and ejection fraction. Recent advances in echocardiography, such as microsphere contrast echocardiography for left ventricular opacification and perfusion imaging, three-dimensional transthoracic and trans-oesophageal imaging, strain and tissue Doppler imaging, all contribute to improving accuracy and reproducibility of these important measurements. Such techniques are now routinely available on standard echocardiography equipment in Australian centres for daily use. Hand-carried ultrasound devices have been developed, which are portable, are affordable and offer increased availability of echocardiography to the wider community. Clinicians should be actively encouraged to adopt these technologies to improve the diagnostic quality and reproducability of echocardiography for our patients. This article provides an overview of important recent advances in echocardiographic imaging with an emphasis on their role in clinical practice today.

Diagnostic accuracy of hospitalist-performed hand-carried ultrasound echocardiography after a brief training program

BACKGROUND

The duration of training needed for hospitalists to accurately perform hand-carried ultrasound echocardiography (HCUE) is uncertain.

OBJECTIVE

To determine the diagnostic accuracy of HCUE performed by hospitalists after a 27-hour training program.

DESIGN

Prospective cohort study.

SETTING

Large public teaching hospital.

PATIENTS

A total of 322 inpatients referred for standard echocardiography (SE) between March and May 2007.

INTERVENTION

Blinded to SE results, attending hospitalist physicians performed HCUE within hours of SE.

MEASUREMENTS

Diagnostic characteristics of HCUE as a test for 6 cardiac abnormalities assessed by SE: left ventricular (LV) systolic dysfunction; severe mitral regurgitation (MR); moderate or severe left atrium (LA) enlargement; moderate or severe LV hypertrophy; medium or large pericardial effusion; and dilatation of the inferior vena cava (IVC).

RESULTS

A total of 314 patients underwent both SE and HCUE within a median time of 2.8 hours (25th to 75th percentiles, 1.4 to 5.1 hours). Positive and negative likelihood ratios for HCUE increased and decreased, respectively, the prior odds by 5-fold or more for LV systolic dysfunction, severe MR regurgitation, and moderate or large pericardial effusion. Likelihood ratios changed the prior odds by 2-fold or more for moderate or severe LA enlargement, moderate or severe LV hypertrophy, and IVC dilatation. Indeterminate HCUE results occurred in 2% to 6% of assessments.

CONCLUSIONS

The diagnostic accuracy of HCUE performed by hospitalists after a brief training program was moderate to excellent for 6 important cardiac abnormalities.

[Echocardiography in the Intensive Care Unit]

The echocardiography can provide important and relevant information and the critically ill patient presents a challenge for the echocardiographer: from limitations in image acquisition to interpretation in the context of rapid physiological and intervention changes. The most frequent reason for requesting an echocardiogram in the ICU is probably to assess left ventricular function. In any case, information of direct relevance for clinical management can in relationship to abnormalities of structure and function can be obtained and used to estimate pulmonary arterial and venous pressures. It can help to investigate the consequences of myocardial ischemia, valvular dysfunction and pericardial disease and detect changes characteristic of specific conditions (e.g. sepsis, pulmonary thromboembolism), although this must be interpreted in the context of each individual patient. The echocardiography also can be used to monitor the therapeutic interventions. The applications of echocardiography in the critical care setting are reviewed, with special emphasis on the assessment of cardiac physiology.

Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS)

Echocardiography is increasingly used in the management of the critically ill patient as a non-invasive diagnostic and monitoring tool. Whilst in few countries specialized national training schemes for intensive care unit (ICU) echocardiography have been developed, specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice are lacking. Further, existing echocardiography accreditation does not reflect the requirements of the ICU practitioner. The WINFOCUS (World Interactive Network Focused On Critical UltraSound) ECHO-ICU Group drew up a document aimed at providing guidance to individual physicians, trainers and the relevant societies of the requirements for the development of skills in echocardiography in the ICU setting. The document is based on recommendations published by the Royal College of Radiologists, British Society of Echocardiography, European Association of Echocardiography and American Society of Echocardiography, together with international input from established practitioners of ICU echocardiography. The recommendations contained in this document are concerned with theoretical basis of ultrasonography, the practical aspects of building an ICU-based echocardiography service as well as the key components of standard adult TTE and TEE studies to be performed on the ICU. Specific issues regarding echocardiography in different ICU clinical scenarios are then described. Obtaining competence in ICU echocardiography may be achieved in different ways - either through completion of an appropriate fellowship/training scheme, or, where not available, via a staged approach designed to train the practitioner to a level at which they can achieve accreditation. Here, peri-resuscitation focused echocardiography represents the entry level--obtainable through established courses followed by mentored practice. Next, a competence-based modular training programme is proposed: theoretical elements delivered through blended-learning and practical elements acquired in parallel through proctored practice. These all linked with existing national/international echocardiography courses. When completed, it is anticipated that the practitioner will have performed the prerequisite number of studies, and achieved the competency to undertake accreditation (leading to Level 2 competence) via a recognized National or European examination and provide the appropriate required evidence of competency (logbook). Thus, even where appropriate fellowships are not available, with support from the relevant echocardiography bodies, training and subsequently accreditation in ICU echocardiography becomes achievable within the existing framework of current critical care and cardiological practice, and is adaptable to each countrie's needs.

The pocket echocardiograph: a useful new tool?

AIMS

Hand-carried ultrasound scanners are getting smaller. The Acuson P10 is the latest and smallest portable echocardiograph available on the market.

METHODS AND RESULTS

We tested the ability of this scanner to allow qualitative assessment of LV size and function in an unselected group of 30 patients [19 male, 11 female; mean age (SD) 64.7 (10.3) years] seen by a consultant cardiologist (accredited for advanced echocardiography) during a week on call in a regional cardiac tertiary facility. Patients had focused scans (parasternal long-axis and apical four chamber views) for a maximum of 4 min, and an assessment of LVEF (normal/abnormal) and LV dimension (LVD) (dilated/non-dilated) was recorded. Where available, this was compared with results of alternative imaging modalities. In 23 (77%) patients, it was possible to assess LVEF and LVD; of these, 19 (83%) had alternative imaging techniques, which confirmed the findings. It was possible to obtain a parasternal long-axis image in 28 (93%) patients and apical four-chamber views in 23 (77%). Clinical management was altered by the findings of the portable scan in two patients.

CONCLUSION

The 'pocket scanner' allows accurate qualitative assessment of left ventricular dimensions and function in a substantial proportion of patients seen in tertiary cardiology practice.

Imaging studies in patients with heart failure: current and evolving technologies

Technological advances continue to expand the clinical role of echocardiography in the intensive care unit, particularly in patients with heart failure. It has many advantages over tomographic techniques such as echo cardiac magnetic resonance imaging and cardiac computed tomography, can provide rapid bedside cardiac assessment, and facilitate emergent decision-making for critically ill patients. Image quality problems in the intensive care setting have largely been overcome by the use of harmonic imaging, contrast opacification, and when indicated, transesophageal echocardiography. Newer techniques promise to advance the scope and prognostic power of echocardiography, and to expand the portability and availability of this tool.

Toward an ultrasound curriculum for critical care medicine

Accurate assessment and rapid decision-making are essential to save lives and improve performance in critical care medicine. Real-time point-of-care ultrasound has become an invaluable adjunct to the clinical evaluation of critically ill and injured patients both for pre- and in-hospital situations. However, a high level of quality is necessary, guaranteed by appropriate education, experience, credentialing, quality control, continuing education, and professional development. Although educational recommendations have been proposed by a variety of nonimaging specialties, to date they are still scattered and limited examples of standards for critical and intensive care professionals. The challenge of providing adequate specialty-specific training, as encouraged by major medical societies, is made even more difficult by the diversity of critical care ultrasound utilization by various subspecialties in a variety of settings and numerous countries. In order to meet this educational challenge, a standard core curriculum is presented in this manuscript. The proposed curriculum is built on a competence, performance, and outcomes-based approach that is tailored to setting-specific training needs and prioritized according to critical problem-based pathways, rather than traditional organ-based systems. A multiple goal-oriented style fully addresses the specialty-specific approach of critical and intensive care professionals, who typically deal with disease states in complex scenarios rather than individual organ complaints. Because of the variation in the concept of what constitutes critical care worldwide, and the rate of change of information and technology, this manuscript attempts to present a learning system addressing a variety of needs for a rapidly changing world.

Bedside echocardiography in the assessment of the critically ill

Advances in ultrasound technology continue to enhance its diagnostic applications in daily medical practice. Bedside echocardiographic examination has become useful to properly trained cardiologists, anesthesiologists, intensivists, surgeons, and emergency room physicians. Cardiac ultrasound can permit rapid, accurate, and noninvasive diagnosis of a broad range of acute cardiovascular pathologies. Although transesophageal echocardiography was once the principal diagnostic approach using ultrasound to evaluate intensive care unit patients, advances in ultrasound imaging, including harmonic imaging, digital acquisition, and contrast for endocardial enhancement, has improved the diagnostic yield of transthoracic echocardiography. Ultrasound devices continue to become more portable, and hand-carried devices are now readily available for bedside applications. This article discusses the application of bedside echocardiography in the intensive care unit. The emphasis is on echocardiography and cardiovascular diagnostics, specifically on goal-directed bedside cardiac ultrasonography.

Specific skill set and goals of focused echocardiography for critical care clinicians

Echocardiography in the critical care setting can provide crucial information about the patient's cardiac anatomy, ejection fraction, valvular function, and volume status. There is a need for more involvement by intensivists in performing focused echocardiographic studies as this modality has been well shown to improve patient care. Several factors limit the widespread use of this technology by intensivists that are noncardiologists. One of them is the lack of formal didactic and practical training programs in "goal-directed" echocardiography specifically oriented for the critical care specialist. Although it is clear that extensive training and experience are needed to perform and interpret a complete echocardiographic study, a growing body of literature demonstrates that noncardiology medical professionals can be trained to acquire and interpret echocardiographic imaging in a goal-directed or "focused" manner with an acceptable overall level of accuracy. Performance of such focused echocardiography by intensivists has been shown to provide new information not assessable by physical examination, and often leads to change in therapeutic management at the bedside. Echocardiography using the transthoracic approach is a noninvasive imaging modality and is of great value in the critical care setting because of its portability, widespread availability, and rapid diagnostic capability. Programs for intensivists should cover both the transthoracic and transesophageal approach. Focused training with the transthoracic approach should be offered to all intensivists, while training with the transesophageal approach should be offered to intensivists who desire more advanced training. This article will go over important issues regarding current and potential avenues for training of critical care physicians in performance of focused bedside echocardiography.

Focused echocardiographic evaluation in resuscitation management: Concept of an advanced life support–conformed algorithm

Emergency ultrasound is suggested to be an important tool in critical care medicine. Time-dependent scenarios occur during preresuscitation care, during cardiopulmonary resuscitation, and in postresuscitation care. Suspected myocardial insufficiency due to acute global, left, or right heart failure, pericardial tamponade, and hypovolemia should be identified. These diagnoses cannot be made with standard physical examination or the electrocardiogram. Furthermore, the differential diagnosis of pulseless electrical activity is best elucidated with echocardiography. Therefore, we developed an algorithm of focused echocardiographic evaluation in resuscitation management, a structured process of an advanced life support-conformed transthoracic echocardiography protocol to be applied to point-of-care diagnosis. The new 2005 American Heart Association/European Resuscitation Council/International Liaison Committee on Resuscitation guidelines recommended high-quality cardiopulmonary resuscitation with minimal interruptions to reduce the no-flow intervals. However, they also recommended identification and treatment of reversible causes or complicating factors. Therefore, clinicians must be trained to use echocardiography within the brief interruptions of advanced life support, taking into account practical and theoretical considerations. Focused echocardiographic evaluation in resuscitation management was evaluated by emergency physicians with respect to incorporation into the cardiopulmonary resuscitation process, performance, and physicians' ability to recognize characteristic pathology. The aim of the focused echocardiographic evaluation in resuscitation management examination is to improve the outcomes of cardiopulmonary resuscitation.

Cost‐Effective Strategies to Screen for Left Ventricular Systolic Dysfunction in the Community—A Concept

Early detection of heart failure caused by left ventricular systolic dysfunction (LVSD) is important, since early treatment has been shown to retard the progression of heart failure. While traditional echocardiography remains the standard for the detection of LVSD, electrocardiography and serum brain natriuretic peptide have also been shown to predict LVSD. Recently, hand-held echocardiography systems have been shown to have high predictive accuracy for assessment of LVSD. With the availability of the above bedside and relatively less-costly techniques, compared with traditional echocardiography, the major question now is what is the most cost-effective strategy for screening subjects for LVSD. To date, no studies have systematically addressed this issue, but preliminary data are becoming available. This review article discusses the pros and cons of various investigative strategies and likely cost-effectiveness of each strategy to screen for LVSD.

A hand-carried cardiac ultrasound device in the outpatient cardiology clinic reduces the need for standard echocardiography

OBJECTIVE

To assess the potential value and cost-effectiveness of a hand-carried ultrasound (HCU) device in an outpatient cardiology clinic.

METHODS

222 consecutive patients were prospectively enrolled in the study. When standard echocardiography (SE) was specifically indicated on the basis of clinical history, electrocardiogram and physical examination, the same cardiologist (level-2 or level-3 trained) immediately performed an HCU examination. The cardiologist then reassessed the clinical situation to confirm or cancel the SE request according to the information provided by HCU. The SE examination was performed by a sonographer and examined in a blinded fashion by a cardiologist expert in echocardiography. Findings from the two examinations were compared.

RESULTS

HCU was performed in 108/222 patients, and a definite diagnosis was established in 34 of them (31%), making SE examination potentially avoidable. In the 74 patients with inconclusive HCU results and for whom SE was still indicated, the decision was mainly dictated by the lack of spectral Doppler modality in the HCU system. The overall agreement between HCU and SE for diagnosis of normal/abnormal echocardiograms was 73% (kappa = 0.4). On the basis of the potentially avoided SE examinations and the obviated need for a second cardiac consultation, a total cost saving of euro2142 per 100 patients referred for echocardiography was estimated.

CONCLUSIONS

The use of a simple HCU device in the outpatient cardiology clinic allowed reliable diagnosis in one third of the patients referred for echocardiography, which translates into cost and time saving benefits.

A Pilot Study of the Clinical Impact of Hand-Carried Cardiac Ultrasound in the Medical Clinic

BACKGROUND

Small, hand-carried ultrasound devices have become widely available, making point-of-care echocardiograms (echos) accessible to all medical personnel as a means to augment and improve the increasingly inefficient physical examination. This study was designed to determine the clinical utility of hand-carried echo by medical residents in clinical decision making.

METHODS

Nine residents underwent brief, practical echo training to perform and interpret a limited hand-carried echo as an integral component of their office examination. The residents' hand-carried echo consisting of four basic views to define left ventricular (LV) function and wall thickness, valvular disease, and any pericardial effusions was compared to one performed by a level III echocardiographer.

RESULTS

Seventy-two consecutive medical clinic patients were enrolled with an average image acquisition time of 4.45 minutes. Residents obtained diagnostic images in 94% of the cases and interpreted them correctly 93% of the time. They correctly identified 92% of the major echo findings and 78% of the minor findings. Their diagnosis of LV dysfunction, valvular disease, and LV hypertrophy improved by 19%, 39%, and 14% with hand-carried echo compared to history and physical alone. Management decisions were reinforced in 76% and changed in 40% of patients with the use of hand-carried echo.

CONCLUSION

This study demonstrates that it is possible to train medical residents to perform an effective and reasonably accurate hand-carried echo during their physical examination, which can impact clinical management.

Bedside ultrasonography in the ICU: part 1

Ultrasonography has become an invaluable tool in the management of critically ill patients. Its safety and portability allow for use at the bedside to provide rapid, detailed information regarding the cardiovascular system and the function and anatomy of certain internal organs. Echocardiography can noninvasively elucidate cardiac function and structure. This information is vital in the management hemodynamically unstable patients in the ICU. In addition, ultrasonography has particular value for the assessment and safe drainage of pleural and intra-abdominal fluid and the placement of central venous catheters. A new generation of portable, battery-powered, inexpensive, hand-carried ultrasound devices have recently become available; these devices can provide immediate diagnostic information not assessable by physical examination alone and allow for ultrasound-guided thoracocentesis, paracentesis, and central venous cannulation. This two-part article reviews the application of bedside ultrasonography in the ICU.

Bedside Ultrasonography in the ICU

This is the second of a two-part review on the application of bedside ultrasonography in the ICU. In this part, the following procedures will be covered: (1) echocardiography and cardiovascular diagnostics (second part); (2) the use of bedside ultrasound to facilitate central-line placement and to aid in the care of patients with pleural effusions and intra-abdominal fluid collections; (3) the role of hand-carried ultrasound in the ICU; and (4) the performance of bedside ultrasound by the intensivist. The safety and utility of bedside ultrasonography performed by adequately trained intensivists has now been well demonstrated. This technology, as a powerful adjunct to the physical examination, will become an indispensable tool in the management of critically ill patients.

Hand-held echocardiography: its use and usefulness

In recent years, several echocardiographic hand-held devices have been developed and are now available for a growing number of cardiologists. After the first clinical use 25 years ago, hand-held echocardiography (HHE) is now earning important commercial positions. Their transportability permits echo performance out the echo-labs and offers the possibility to make diagnosis in intensive care unit, emergency room, outpatient clinic, at the bedside, and even in ambulance. Experiences in the clinical setting have demonstrated the ability of HHE to detect multiple diseases including abdominal aortic aneurysms, left ventricular hypertrophy, regional wall motion abnormalities, pericardial and pleural effusions. At the present time, four varieties of HHE have to be recognized: the first includes high-cost, miniaturized machines, similar to the most advanced instrumentations, provided by new tools and imaging transfer systems; a second intermediate, middle-cost variety encompasses devices corresponding to standard echocardiography, but not miniaturized; according to the definition of the American Society of Echocardiography, a third and a fourth category comprise machines of weight lower than 2.7 kg, battery supplied and appropriately defined as "portable cardioschopes", which can be utilized as a technical refinement of physical examination. The use of HHE opens main controversy concerning their diagnostic accuracy, the opportunity to establish in which clinical settings they should be used and the identification of both potential users and required competence level. Preliminary experiences show the possibility to improve and anticipate diagnosis of several cardiovascular diseases but also the need to plan specific ultrasound training to avoid incorrect use of HHE.

The Use of Hand-carried Ultrasound in the Hospital Setting-A Cost-effective Analysis

OBJECTIVES

We sought to assess the accuracy of hand-carried ultrasound (HCU) in the prediction of a normal study, and its cost-effectiveness in reducing the number of standard departmental echocardiograms (SDE) performed on hospital inpatients.

METHODS

The setting was a district general hospital. Participants were 157 consecutive inpatients, mean age 68 (range: 18-97) years, 95 men (61%), referred for SDE. HCU was performed at the bedside as part of the clinical assessment. SDE was performed routinely. Main outcome measures were: (1) assessment of the accuracy of HCU in detection of a normal or abnormal study as determined by SDE; and (2) a cost-effectiveness analysis.

RESULTS

Indications for echocardiography were: left ventricular (LV) function assessment, n = 101 (64.3%); valvular abnormalities, n = 11 (7%); arrhythmia, n = 4 (2.6%); miscellaneous, n = 10 (6.4%); and no reason stated, 31 (19.7%). The sensitivity, specificity, and positive and negative predictive values of HCU predicting a completely normal scan were 74%, 96%, 94%, and 81%, respectively, and of predicting normal LV function in requests specific for LV function assessment were 81%, 100%, 100%, and 77%, respectively. If either all inpatients or those with requests for LV function assessment underwent HCU initially, and only those with abnormal scans underwent further SDE, there would be a 29% and 22% reduction in departmental workload and a cost saving of pound sterling 23,000 and pound sterling 30,000, respectively.

CONCLUSION

HCU is an accurate method of identifying patients with normal hearts as determined by SDE. Its routine use is cost-effective and can significantly reduce the number of SDE that need be performed.

Use of a hand-carried ultrasound device by critical care physicians for the diagnosis of pericardial effusions, decreased cardiac function, and left ventricular enlargement in pediatric patients

Prompt diagnosis of children with suggested cardiac disease in the acute care setting is critical for initiation of life-saving therapy. We hypothesized that pediatric critical care physicians could perform limited portable echocardiography in children. Portable hand-carried cardiac ultrasound units with 2.5-MHz phased-array transducers were used (Optigo, Philips Medical Systems, Andover, Mass). Noncardiologists were trained through a 1-hour introductory course and 2 hours of practical training. Portable echocardiography performed by noncardiologists was compared with a standard echocardiogram for diagnostic accuracy. In all, 23 patients (age 3 months-20 years) were screened during 18 months. The presence or absence of a pericardial effusion was correctly diagnosed in 21 of 23 patients (91%). Left ventricular size was correctly determined in 22 of 23 patients (96%). Left ventricular systolic function was correctly diagnosed in 22 of 23 patients (96%). These results show that, with appropriate instruction, pediatric critical care physicians are effective using limited portable echocardiography.

Technology Insight: hand-carried ultrasound cardiac assessment—evolution, not revolution

Hand-carried ultrasound devices can enhance the art of bedside physical examination by increasing diagnostic accuracy, detecting disease at an earlier stage, and improving triage and referral of patients. Although limitations of device cost and portability can be overcome with technologic advances, the shortage of standardized imaging and training opportunities now needs to be addressed to move the technique forward. Cardiologists are the best-qualified subspecialists to design and teach a simplified training program for bedside use of hand-carried ultrasound devices to assess the cardiovascular system.

Evaluation of a hand carried cardiac ultrasound device in an outpatient cardiology clinic

OBJECTIVE

To determine the diagnostic potential of a hand carried cardiac ultrasound (HCU) device (OptiGo, Philips Medical Systems) in a cardiology outpatient clinic and to compare the HCU diagnosis with the clinical diagnosis and diagnosis with a full featured standard echocardiography (SE) system.

METHODS

300 consecutive patients took part in the study. The HCU examination was performed by an experienced echocardiographer before patients visited the cardiologist. The echocardiographer noted whether the HCU device was able to confirm or reject the referral diagnosis, which abnormality was detected, and whether SE investigation was necessary. Physical examination by a cardiologist followed and thereafter, whenever required, a complete study with an SE was carried out. The HCU data were compared with the clinical diagnosis of the cardiologist and the SE diagnosis in a blinded manner.

RESULTS

The cardiologist referred 203 of 300 patients for an SE study and 13 patients for transoesophageal echocardiography. In 84 patients no further examination was considered necessary. HCU echocardiography was able to confirm or reject the suspected clinical diagnosis in 159 of 203 (78%) patients. In 44 of 203 (22%) patients SE Doppler was needed. Agreement between the HCU device and the SE system for the detection of major abnormalities was excellent (98%). The HCU device missed 4% of the major findings. Among the 84 patients not referred for an SE, the HCU device detected unsuspected major abnormalities missed with the physical examination in 14 (17%).

CONCLUSION

Integration of an HCU device with the physical examination augments the yield of information.

Bringing MRI to the cardiologist: can we learn from echocardiography?

Cardiac MRI (CMR) is a low-risk, comprehensive diagnostic tool that has many similarities with echocardiography. It is noninvasive, lacks ionizing radiation, and the contrast material used to enhance various images does not have any renal toxicity. Although extremely valuable in the diagnosis of neurologic and musculoskeletal diseases for more than two decades, CMR has only recently become relevant for diagnosing the rapidly beating and constantly mobile heart. Through advances in cardiac gating and high-speed acquisition software, CMR is positioning itself as a critical utensil at the cardiovascular disease banquet. However, like echocardiography, currently celebrating its 50th birthday, CMR is likely to suffer occasional growing pains, along with its share of accomplishments. Therefore, those practicing CMR should learn from the past errors and achievements of echocardiography in an effort to deliver the most rewarding diagnostic instrument imaginable, without having to wait 50 years.

A time of accelerated change in academic cardiovascular medicine

With the vast epidemic of vascular disease predicted to be the leading cause of death and disability by a growing margin over the next 30 years, academic medical centers with cardiology training programs have a special responsibility. Given the dramatic advances of biotechnology in producing highly effective but expensive strategies of prevention and treatment, cardiovascular specialists should assist their academic centers in envisioning the future to prepare trainees for a different environment. Cardiologists of the future must be able to adapt to a societal need for patient-oriented, team-based clinical care and rapidly evolving technology, while maintaining the fundamental skills and knowledge required for individual patient interaction. Academic programs should benchmark their activities to ensure responsible resource allocation so that cardiologists of the future will be trained in an environment stimulating excellence and creativity.

Ultrasound stethoscopy

Miniaturization and digital techniques have resulted in the development of high-resolution, battery-powered personal ultrasound devices with excellent grey-scale and color blood flow imaging capabilities. These devices are appropriately called "ultrasound stethoscopes" and are practical to use. They extend our physical perception during a clinical examination by "seeing the invisible pathology" and allow the user to address specific clinical problems anywhere at the point-of-care. Murmurs and abnormal precordial movements can be directly related to cardiac structural, functional, and flow abnormalities. A cardiac abnormality (pericardial effusion, dilated heart, valvular disease, mass lesion) is rapidly confirmed during the clinical examination and often a specific diagnosis is made. The device can effectively assist in the initial evaluation and rapid diagnosis of potentially life-threatening conditions or in situations where quick decision-making is essential. Overall, they strengthen our clinical diagnostic accuracy and also add quantitative information. The ultrasound stethoscope allows rapid screening for left ventricular dysfunction and occult aortic abdominal aneurysm and left ventricular hypertrophy in patients with hypertension. Training may become an important issue and should focus on criteria of normalcy and identifying specific and major cardiac disorders. There is no doubt, however, that these devices will revolutionize the physical cardiac examination and diagnosis.

Hand-Carried Ultrasound Improves the Bedside Cardiovascular Examination

OBJECTIVES

We assessed the clinical utility of hand-carried cardiac ultrasound (HCU) devices to assist physicians in the diagnosis of cardiovascular disease.

MATERIALS AND METHODS

We reviewed 42 articles published from 1978 to 2004.

RESULTS

The capability and simplicity of the HCU device assist physicians in the diagnosis of cardiovascular disease at the initial patients contact. HCU is particularly useful in the setting of emergency or critical care, community screening, or in remote areas with limited access to health care.

CONCLUSION

The inherent limitations of the physical examination as well as the reduced focus and training in physical diagnosis of current and recent medical school graduates has set the stage for the HCU device to modify traditional medical practices by complementing the physical examination with real-time cardiovascular imaging.

Hand-carried cardiac ultrasound as a tool to screen for important cardiovascular disease in an underserved minority health care clinic

The disparity in cardiovascular outcomes among racial and social strata may be, in part, because of delayed detection of cardiovascular disease in minority patients. The low cost and portability of hand-carried cardiac ultrasound devices may make screening of underserved patients for cardiac disease feasible. A general internist evaluated 153 patients at a clinic serving an underserved population with a hand-carried cardiac ultrasound device. A total of 27 cases of significant valvular heart disease or ventricular dysfunction were detected in 19 patients (12.4%). Detection of a major cardiac abnormality could not be predicted by cardiac risk factors, age, or chief symptom, whereas patients presenting for new or acute clinic visits were more likely to have an abnormality. The low cost and portability of hand-carried cardiac ultrasound devices may make them important tools for the early detection of cardiovascular disease in minority and underserved populations and, thereby, help to reduce disparities in cardiovascular outcomes.

Usefulness of a hand-carried cardiac ultrasound device to detect clinically significant valvular regurgitation in hospitalized patients

The accuracy of a hand-carried cardiac ultrasound (HCCU) device for the diagnosis of valvular regurgitations using color-flow Doppler was assessed. One hundred twenty hospitalized patients with at least mild valvular regurgitation by standard echocardiography were evaluated by 2 cardiologists using HCCU. The HCCU operator identified 99% of clinically significant valvular regurgitations and assessed the severity correctly in 83% of cases. For mild regurgitation, the HCCU sensitivity and specificity were 82% and 93%, respectively, resulting in correct assessments of severity in 71% of cases. HCCU used by trained cardiologists has high sensitivity for the detection and accurate assessment of the severity of clinically relevant valvular regurgitation.

Development of an ultra-portable echo device connected to USB port

In practical cardiology, a stethoscope based auscultation has been used to reveal the patient's clinical status. Recently, several hand-held echo devices are going on market and they are expected to play a role as "visible" auscultation instead of stethoscope. We have developed a portable and inexpensive echo device which can be used for screening of cardiac function. Two single element transducers were attached 180 degrees apart to a rotor with 14-mm diameter. The mechanical scanner, integrated circuits for transmitting and receiving ultrasonic signals and an A/D converter were encapsulated in a 150 x 40 mm probe weighing 200 g. The scan was started and the image was displayed on a Windows based personal computer (PC) as soon as the probe was connected to USB 2.0 port of the PC. The central frequency was available between 2.5 and 7.5 MHz, the image depth was 15 cm and the frame rate was 30/s. The estimated price of this ultra-portable ultrasound is about 3000 US dollars with software. For 69 cardiac patients with informed consent, image quality was compared with those obtained with basic range diagnostic echo machines. Left ventricular ejection fraction (EF) derived from normal M-mode image of standard machines (EFm) were compared with visual EF of the ultra-portable ultrasound device (EFv). The image quality was comparable to the basic range diagnostic echo machines although short axis view of aortic root was not clearly visualized because the probe was too large for intercostal approach. EFv agreed well with EFm. The ultra-portable ultrasound may provide useful information on screening and health care.

Feasibility of point-of-care echocardiography by internal medicine house staff

OBJECTIVE

To determine whether internal medicine house staff with limited training in echocardiography can use point-of-care echocardiography to make simple, clinically important diagnoses.

BACKGROUND

Availability of small, portable ultrasound devices could make point-of-care echocardiography widely available. The training required to perform point-of-care echocardiography has not been established.

METHODS

Medical house staff participated in a 3-hour point-of-care echocardiography training program. Patients scheduled for standard echocardiography as part of clinical care underwent point-of-care echocardiography within 24 hours to assess four common clinically important diagnoses. Each standard echocardiogram was interpreted twice. Agreement (kappa) was calculated between point-of-care and standard echocardiography by using standard echocardiography as the gold standard and between the two interpretations of standard echocardiography.

RESULTS

Agreement (kappa) between point-of-care echocardiography and standard echocardiography was 75% (0.51) for left ventricular dysfunction (ejection fraction <55%), 79% (0.31) for moderate or severe mitral regurgitation, 92% (0.32) for aortic valve thickening or immobility, and 98% (0.51) for moderate or large pericardial effusion. Agreement between the two interpretations of standard echocardiography was 83% (0.63) for left ventricular dysfunction, 92% (0.68) for moderate or severe mitral regurgitation, 95% (0.62) for aortic valve thickening or immobility, and 97% (0.53) for moderate or large pericardial effusion.

CONCLUSIONS

Medical house staff with limited training in echocardiography can use point-of-care echocardiography to assess left ventricular function and pericardial effusion with moderate accuracy that is lower than that of standard echocardiography. Assessment of valvular disease and other diagnoses likely requires more training and/or experience in echocardiography.

Influence of hand-carried ultrasound on bedside patient treatment decisions for consultative cardiology

To test the hypothesis that hand-carried ultrasound (HCU) may influence patient treatment on consultative cardiology rounds, 235 patients who were hospitalized (aged 65 +/- 10 years) were studied. First, routine treatment decisions regarding diagnostic workup and therapy were made from patient history, physical examination, 12-lead electrocardiogram, and chart data. Second, a goal-directed HCU study was performed in <10 minutes focusing on left ventricular global and regional function, wall thickness, and presence of pericardial effusion, followed by a reassessment of treatment decisions. HCU data influenced treatment decisions in 149 patients (63%); 50% had a change in medical therapy and 22% had a change in their diagnostic workup (most with changes in both). In all, 12 patients (5%) had an immediate change in the decision for cardiac catheterization or pericardiocentesis. Overall agreement for the above findings with subsequent full-size system echocardiography ranged from 92% to 100% (kappa 0.91-0.96). Goal-directed HCU has the potential to influence bedside patient treatment decisions and expedite health care.

Screening for left ventricular dysfunction using a hand-carried cardiac ultrasound device

BACKGROUND

The hand-carried cardiac ultrasound (HCU) device is a recently introduced imaging device, which may be potentially useful in the primary care setting.

AIM

To test the screening potential of a HCU for the detection of left ventricular (LV) dysfunction by evaluating LV ejection fraction (LVEF) and inferior vena cava (IVC) collapse. Standard echocardiographic system (SE) and plasma brain natriuretic peptide (BNP) measurements were used as a reference.

METHODS

Eighty-eight consecutive patients (56 male, aged 59+/-12 years) with suspected LV dysfunction were enrolled in the study. The HCU-LVEF was visually estimated and the SE-LVEF was derived by the Simpson's biplane method. A LVEF <40% represented LV dysfunction. An IVC collapse of <50% and BNP levels > or =15 pmol/l were considered abnormal. The correlation of HCU-LVEF, HCU-IVC and BNP to the SE-LVEF and SE-IVC was analysed independently using 2x2 tables.

RESULTS

Six patients were excluded because of poor echo images. 19/82 patients had LV dysfunction. The HCU and BNP could identify 17 and 18 out of these 19 patients, respectively. The agreement for LVEF and IVC collapse between SE and HCU was 96% for both parameters. The sensitivity of IVC collapse, HCU-LVEF and BNP in identifying patients with LV dysfunction was 26, 89 and 94%, respectively.

CONCLUSION

A HCU device can reliably be used as a screening tool for LV dysfunction.