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

The application of echocardiography in the critically ill has been well-recognized for several years, principally in patients following cardiac surgery [1‐6]. The use of this technique is presently expanding to include diagnosis and monitoring on the general intensive care unit (ICU) [7‐14]. Further, as echocardiography is an evolving technology with broadening applications throughout medical and surgical practice, and equipment is becoming cheaper, more portable and more widely available [15‐19], it is inevitable and appropriate that medical practitioners other than cardiologists and echocardiographers should seek to develop skills in the performance of ICU echocardiography.

Currently there are no specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice. Despite this, many are recommending that echocardiography should be incorporated into ICU training programs due to its ability to positively impact on patient management [20‐35]. However, due to the complexity of issues involved, few have developed specialized national training schemes for ICU echocardiography [28, 36, 37] and echocardiography accreditation (through EAE, BSE or the ASE) does not reflect the requirements of the ICU practitioner, as they contain heavy emphasis on valvular disease, little haemodynamic monitoring, and an absence of pathology in the critically ill. The World Interactive Network Focused on Critical UltraSound (WINFOCUS, http://​www.​winfocus.​org) is a scientific society committed to the development of high-quality ultrasound in the emergency and ICU setting, including echocardiography. This document has been prepared from recommendations published by the Royal College of Radiologists [38], and British Society of echocardiography [39], European Association of Echocardiography [40] and American Society of Echocardiography [4], together with input from established practitioners of ICU echocardiography to provide guidance to individual physicians (and also to inform program directors, the relevant echocardiographic and intensive care societies, hospital administrators and health care policy makers) of the requirements involved in the development of skills in echocardiography in the ICU setting. Although the authors recognise that ICU clinicians may use ultrasound to image other organ systems, for the purposes of clarity these recommendations are limited to training and accreditation in echocardiography. Recommendations for training of non-radiologists in the imaging of other organ systems exist [38, 41], and WINFOCUS projects already include systematic development of a comprehensive ultrasound curriculum for the intensivist and critical care physician [23, 42].

Point-of care echocardiography has become an indispensable tool in the management of the critically ill patient, providing rapid assessment of cardiac function and physiology that complements data available from standard invasive hemodynamic monitoring [8‐12, 28]. This expanding use of echocardiography may also have been driven by recent publications that have raised concerns regarding pulmonary artery catheterisation [43‐48]. Further, the technological advances leading to progressive miniaturization of systems, and advances in echocardiographic techniques (including harmonic imaging, digital acquisition and contrast-enhanced endocardial definition) together with the development of more portable echocardiographic systems has led to their increased use in the ICU. Here, echocardiography is uniquely useful in providing both a monitoring and diagnostic tool for rapid bedside assessment of cardiovascular pathophysiology in the critically ill [12, 30, 49]. In contrast to standard diagnostic studies, frequently answers to specific questions are required (e.g. loading and volume responsiveness, cardiac output, ventricular function) rather than a fully comprehensive study. Despite enthusiasm for its use by specialists, there is little data to prove the benefit of echocardiography on the ICU. A number of studies have, however, indicated its potential usefulness in changing the diagnosis and management of the critically ill [29‐35], together with assessment of ventricular function [10, 50‐53] fluid responsiveness [54] and the hemodynamics of shock states [8, 9, 12, 55, 56].

In addition to standard echocardiography skills, an ICU echocardiographer must be able to interpret findings from both trans-thoracic and trans-esophageal studies, to expeditiously answer specific questions in the context of the rapidly changing pathophysiological status of the critically ill patient, and be accessible for continued echocardiographic monitoring. This, in addition to having the necessary experience to recognize the need for a more detailed study and referral to a more experienced practitioner. Thus, a training and accreditation process targeted at ICU echocardiography must encompass a practice that differs from regular echocardiography, and presents a real challenge. Furthermore, it is essential that ICU echocardiography is incorporated into a co-ordinated echocardiography service, and requires continued communication with cardiologists, echocardiographers and departments of echocardiography.

Competence in echocardiography and other ultrasound techniques is generally separated into three distinct levels[23, 38, 57‐59] (Figure 1). Although emergency echocardiography is currently being considered as a potential core skill for the acute physician, this covers a limited differential diagnosis, and does not equate to Level I training [30, 60, 61]. Whilst for emergency physicians this level of competence (peri-resuscitation focused echocardiography) may be regarded as adequate, the practicing ICU physician trained in echocardiography will require competencies beyond this. In order to achieve this, a degree of flexibility, reflecting the practice and time-constraints of the ICU physician, will be required, when compared to achieving an equivalent standard for cardiologists.

Despite echocardiography having historically been exclusively the domain of the cardiologist, with the development of TEE and its use in the cardiac surgical setting, its use has extended to anaesthetists. Indeed, in the UK > 90% of TEE studies are now undertaken by anaesthetists. This extension of echocardiography beyond the specialty of cardiology is likely to continue. Focused echocardiography as an adjunct in the peri-arrest period is likely to become a core competency for acute medicine trainees [61], and with the increasing recognition of the potential role of echocardiography on the ICU, international training recommendations now include basic echocardiography [62]. Whether this should extend to intensivists becoming fully trained and accredited in echocardiography remains, for some, contentious.

Although specialist training in cardiology will generally include TTE to level 2 equivalence (or accreditation), cardiology training programmes often excludes formal exposure to general ICU. Further, the specific conditions most relevant to the ICU (i.e. sepsis, filling status, ventricular function related to the level of inotropic support, heart-lung interactions in mechanically ventilated patients) are not generally addressed, and the use of echocardiography as a monitoring tool is not taught. In addition, the diagnosis of pathology in the ICU is on occasion better resolved with TEE rather than TTE. Finally, ready availability of appropriately trained consultant cardiologist-echocardiographers for the repeated examinations required in the ICU is not always possible.

By contrast, the practicing intensivist has a wide knowledge of the pathophysiology of the critically ill, and is readily available, but may not have the necessary echocardiographic skills. When such intensivists have been appropriately trained to perform TTE, TEE and physiological echocardiography, they will be ideally positioned to perform ICU echocardiography. Development of an appropriate program will require extensive cooperation and support form a hospital's cardiology service. This support extends beyond initial training to include support for quality assurance, maintenance of competency among the ICU practitioners and most importantly backup in the case of a difficult diagnosis or one beyond the daily scope of practice of the ICU echocardiographer. An example of such a diagnosis could be evaluation of a mitral valve for suitability for repair.

These recommendations 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 [39]. These recommendations are summarized in Appendices 1 through 3. The intended benefits of these recommendations are to support the development of local protocols and quality control programs for echocardiography on the ICU, promote quality by defining a minimum dataset of descriptive terms and measurements, and a systematic approach to constructing a report, to facilitate the accurate comparison of serial echocardiograms performed in ICU patients. These recommendations are in line with recommendations from the European Association of Echocardiography [63, 64] and the British Society of Echocardiography [65].

Accrediting authorities in echocardiography are not generally proscriptive in how the trainee achieves the standard required for accreditation, but rather in setting the standard [BSE, EAE, ASE]. Education of cardiologists in echocardiography is generally achieved as part of a standard training scheme with supervised, hands-on experience combined with attendance at existing national and international courses. Similarly, cardiothoracic anaesthetists wishing to become accredited in TEE will generally spend time in a cardiothoracic centre undertaking a specific fellowship, together with attendance at appropriate courses – some directed specifically towards examination preparation [59]. The main challenge for trainees and existing consultant intensivists is how to achieve training and accreditation in ICU echocardiography when specific fellowships and/or diplomas are not available. Time limitations and lack of access to training in the ICU generally causes an issue for intensivists – together with lack of expertise in this rapidly expanding field. Hence, this document seeks to suggest ways in which this training may be achieved, whilst maintaing the standards of accreditation required by the echocardiography societies.

ICU echocardiography should be set up as part of the hospital's comprehensive service. Thus, standards of an accredited centre will apply with respect to staff, organisation and equipment [64], to guarantee standards of performing and reporting examinations, even when focused studies are being performed. Thus, even when performing a TOE on a sedated, intubated and ventilated patient, the operator should not be responsible for anaesthesia, the airway or the haemodynamics of the patient [40, 63]. This is particularly relevant in the haemodynamically unstable patient, and/or where more advanced studies (i.e. pacing optimisation/stress echocardiography) are performed.

To a large extent, intensive care has developed in parallel, but separate from cardiology, with little use of the range of physiological measurements and assessments that echocardiography has to offer. This is unsurprising, given the different training pathways that have been followed by intensivists and cardiologists. Indeed, echocardiography has been regarded as the province of the cardiologist since its inception nearly 50 years ago. With increased sub-specialization in the cardiological field, and the development of acute cardiac care as a specific sub-specialty, it is likely that some cardiologists of the future will extend their role into the cardiac ICU setting.

The intensivist is, however, uniquely positioned to understand and balance the multi-system pathophysiological variables that underpin critical illness – both in the cardiac and general ICU setting. It is entirely appropriate therefore that intensivists should be able to develop echocardiographic skills, but consequently it is crucial that they should be able to obtain the necessary echocardiographic training such that they are able to practice this physiological investigation to a high level within their intensive care units. Not all intensivists will wish to (or need to) obtain this higher level training in echocardiography, however, every intensivist undergoing training should be competent in peri-resuscitation echocardiography. Where intensivists do wish to develop their echocardiographic skills, their goal should be a recognised accreditation through an established national or international body. This is achievable through collaboration between the existing accrediting authorities and the relevant national and international intensive care socieities – in a manner analogous to that in which TEE accreditation for anaesthetists was developed. The process by which training is obtained remains a challenge, however, the combination of practical training under supervision with interactive on-line learning will facilitate this process where there is no opportunity for an ICU echocardiography fellowship. As with TEE training for cardiac anaesthetists, it is important that this accreditation should be regarded as an entry level requirement for those who wish to develop echocardiographic skills relevant to the ICU setting. ICU echocardiography should not be practiced in isolation, but in conjunction with consultant (echo)cardiologists as part of a comprehensive echocardiography service. In this way, one would hope to see the performance of high quality, relevant echocardiography, together with well-devised and executed research in this rapidly expanding field.

This basic theoretical training is a prerequisite to any practical training in echocardiography.

Although training in ICU echocardiography is divided into levels of competence, as already described [Additional file 3] clear demarcation between the levels is not absolute, and the practicalities of obtaining training in echocardiography provide specific challenges to both the trainee and their supervisor. Where echocardiography fellowships of appropriate focus and duration are not available, WINFOCUS suggests a supervised modular approach to obtaining echocardiographic skills, comprising emergency, introductory, and intermediate stages. On completion of all modules, it would be anticipated that the practitioner would have performed the number of studies and achieved the competency to undertake a recognised accreditation examination [Additional file 3] through a national/international accrediting body. An outline of the modular structure is described [Additional file 4], followed by a description of training requirements at each level. The modules are described in detail in Appendix 5.