TS Eliot, Four Quartets (Little Gidding)

The four authors of this article share a combined century of experience in critical care echocardiography (CCE). Having seen its birth, adolescence and subsequent maturity, it is with considerable interest that we anticipate further evolution of its everyday clinical application, and can only guess at how the next generation’s energy and interests will be directed. Trained to intervene when a patient’s physiology becomes unstable, intensivists search for effective strategies to tackle acute problems while simultaneously considering complex underlying chronic ailments. Echocardiography is a valuable tool for the diagnosis and monitoring of a patient’s response, or perhaps lack of response, to our interventions. The evolution of critical care echocardiography from being an outcast to that of a mainstream “darling” over the past 30 years led us to give a personal perspective on this journey.

 

The initial offering of heart ultrasound in the hospital setting was that of interrupted M-mode lines extracted from unwieldy mechanical transthoracic transducers producing low fidelity images. In the early 1970s, Dutch engineer Nicolaas Bom invented two-dimensional (2D) echocardiography, with moving 2D slices of the heart appearing on primitive screens. ¹ Sections of the intensive care world displayed keen interest in echocardiography from the early 1980s. In Paris, Francois Jardin and colleagues ² were among the first to use 2D echocardiography to investigate ventricular function in critical illness. Parallel to developments in France, Belgium and the Soviet Union, where single intensivists were probing echocardiography applications in the critically ill, in Australia, three pioneers, Karl Donovan from Perth, Western Australia, and Don Stewart and Anthony McLean from Nepean, New South Wales were actively exploring the role for bedside CCE. ³
 

Dynamic 2D imaging provided a non-invasive window into cardiac function, an exciting tool for cardiologists, yet at that time not within reach of critical care physicians. Wide adoption of pulmonary artery catheters allowing haemodynamic evaluation pulled intensivists into the world of invasive cardiac monitoring. However, further refinement of ultrasound technology, including spectral and colour Doppler, allowed evaluation of intracardiac blood flow and quantification of pressure gradients, placing non-invasive haemodynamic monitoring firmly in the spotlight. Large, heavy and expensive equipment coupled with the need for well trained personnel inhibited its spread into intensive care units (ICUs). To great frustration of the pioneers, what looked like an obvious need for a deteriorating patient was often impossible to provide.
 

A major investigative enhancement, transoesophageal echocardiography (TOE), arrived in the late 1980s. The original bulky mechanical array tips were soon replaced by smaller, less invasive and more sophisticated phased array transducers. Cardiac anaesthetists quickly appreciated the value of TOE in the perioperative setting, and during the 1990s excellent textbooks and other educational material on the subject began to appear. ⁴ Andrew Hilton (Figure 1) was an early pioneer trained in TOE at Duke University Medical Center. He was initially located at Westmead Hospital, later bringing his unique expertise to The Alfred and, consequently, to the rest of the Australian intensive care community, leading critical care echocardiography service, research and education at the major tertiary university ICU in Australia for over a decade. In parallel, few other sites around the country were independently developing CCE. The first Australian TOE course for anaesthetists and intensivists was conducted in Devonport, Tasmania, in 2002, led by Stan Yastrebov and the Tasmanian Institute of Critical Care. The course hosted Professor Terry Rafferty from Yale University, and was largely supported by pioneering speakers from Westmead Hospital and the Royal Melbourne Hospital cardiac anaesthesia departments and Roman Kluger from St Vincent’s Hospital (Melbourne). The Postgraduate Diploma in Perioperative and Critical Care Echocardiography was established at the University of Melbourne by Colin Royse and Alistair Royse. It was supported by a small steering committee group in 2003, comprised of Paul Soeding from the Royal Melbourne Hospital, Roman Kluger from St Vincent’s Hospital (Melbourne), David Sidebotham from Auckland City Hospital (New Zealand), Stan Yastrebov from Mersey Hospital in Tasmania, Michael Veltman and John Faris from WA, and the eminent Westmead Hospital cardiac anaesthesia group. For the first time in Australia, this successful Diploma course offered structured echocardiographic education for a whole generation of Australian anaesthesia and intensive care practitioners, remaining highly relevant and operational to date. It was an exciting time for critical care TOE enthusiasts, with sentinel research being performed on fluid responsiveness, left atrial pressure measurements, cardiopulmonary interactions, and mitral valve function. An increasing focus on detailed haemodynamic evaluation began to differentiate critical care from cardiology echocardiography, the latter with a focus on pathological and anatomical diagnoses. Time imperatives also separated the two groups, with intensivists needing to perform, interpret and act urgently in a highly dynamic environment. Advances in ultrasound technology resulted in much improved transthoracic echocardiography (TTE) images, pushing the tendency for TOE to dominate the critical care scene aside. This trend was evident not only in Australia but also globally. In particular, the recognised leader in critical care echocardiography, France, developed strongly in both modalities, yet over time more TTEs were being performed than TOEs. It is recognised now that both techniques are important for the practice. The upside of having TOE skills becomes obvious in some ventilated patients, those on extracorporeal support, and perioperatively, and is balanced by the challenges of providing good training and skill maintenance. Another important factor in the expansion of echocardiography use as an everyday tool in the ICU is that despite the considerable advances in hardware (smaller, mobile, less expensive scanners) and software (harmonic imaging, tissue Doppler imaging, three-dimensional, speckle tracking, strain, contrast, vortex), the relative size and cost of machines has reduced over the years. Of note, some recent innovations, such as harmonic imaging and speckle-tracking-based strain imaging gained increasing relevance to the critical care setting, while others, such as myocardial perfusion imaging, remain underutilised at this stage. One example of Australia’s prominence on an international CCE stage is on the topic of right ventricular strain, with recent research by Sam Orde, accompanied by obtaining a PhD, ⁵ becoming a reference point for studies in other countries.
 

Several Australian facilities became fully proficient in advanced modern echocardiographic procedures and served as centres of excellence in CCE. One not-for-profit, charitable organisation deserves particular mention, as it was dedicated to the promulgation of CCE. This was the Nepean Institute of Critical Care Education and Research (NICCER), which was founded in the early 2000s. NICCER has conducted over 100 basic (Rapid Assessment by Cardiac Echo [RACE] courses) and advanced courses and forums in CCE in Australasia and Europe, as well as an annual CCE conference held in Leura, NSW, bringing together leading CCE practitioners from around the world for nearly 20 years. In addition, several textbooks and monographs on basic, advanced and expert level CCE have originated from Australia in recent years, underpinning local education and our high international standing. ^{6, 7, 8}
 

 

While the cost of equipment and a lack of training opportunities were impediments to interested intensivists taking up CCE in earlier years, another major factor was that of medical specialty “turf wars”. The first was when cardiac anaesthetists sought Medicare reimbursement for perioperative TOEs. Initial resistance by the cardiology fraternity was subsequently overcome, with over a hundred individual and institutional submissions to the Australian Health Insurance Commission. A second visible confrontation occurred in the early part of this century when intensivists challenged the remuneration monopoly that cardiologists historically had in charging for studies performed on patients in the ICU. This gradual and frustrating period for intensivists necessitated identifying and then obtaining relevant qualifications from both overseas and national certifying bodies, moving beyond having older equipment (usually hand-me-downs from cardiology) to accessing modern machines, and obtaining local institution credentialing. Recent changes in the Medicare Benefits Schedule for ultrasound services are a reminder that vigilance by the intensive care community in this issue is still essential.
 

Adoption of any new technology or procedure requires pioneers, and in Australia, a small number of departments of intensive care medicine led the way, often in spite of local and countrywide opposition: the Nepean Hospital in NSW, the Royal Perth Hospital in WA, Mersey Hospital in Tasmania, The Alfred in Victoria, and the Princess Alexandra Hospital in Queensland. They also served as beacons for individuals working in ICUs where the demands of clinical work combined with a dearth of training opportunities made local echocardiography training impossible. For many years, the mainstream intensive care fraternity ignored echocardiography, and dedicated training was a low priority within intensive care training bodies.
 

The Joint Faculty of Intensive Care Medicine (JFICM) demonstrated little interest in echocardiography training and practice, and the first initiative was by the Australian and New Zealand Intensive Care Society (ANZICS), when then President Ian Jenkins created a joint JFICM/ANZICS CCE Committee in 2006. Continued indifference by senior members of the JFICM resulted in a lack of meaningful achievement and the joint Committee was dissolved in 2009. Interestingly, this was completely at odds with the international critical care community, where many of the major training bodies, recognising the potential value of CCE, came together in 2008 under the aegis of the European Society of Intensive Care Medicine to create consensus guidelines. ⁹ Attended by two of the authors of this article and involving many intensive care societies from around the world, this was an important contribution to CCE, by separating competency into the two levels, basic and advanced, and also outlining training criteria for the basic level. A second international workshop followed in 2014, this time with an emphasis on the advanced level of competency. ¹⁰ Since then, there has been a gradual and progressive acceptance for CCE within the College of Intensive Care Medicine of Australia and New Zealand (CICM) Board.
 

A parallel process was the engagement with a recognised binational (Australia and New Zealand) organisation totally devoted to the practice of ultrasound in medicine, the Australasian Society for Ultrasound in Medicine (ASUM). Negotiations were led by the Nepean Intensive Care group and eventually resulted in the establishment of a dedicated Certificate in Clinician Performed Ultrasound (CCPU), and the Diploma of Diagnostic Ultrasound (DDU Critical Care) in 2012. Internal resistance within ASUM to recognise intensive care medicine as being independent from cardiology had to be overcome. Over time, the DDU (Critical Care) has become the benchmark of quality for advanced level echocardiography training in Australia and New Zealand.
 

The growing maturity of the critical care ultrasound community was reflected by the establishment of the Ultrasound Special Interest Group (USIG) within CICM in 2015. This group is now the largest and most active special interest group within the College, involving over 120 Fellows. Over the past 5 years, it has produced multiple guidelines and recommendations on critical care ultrasonography, specified standards, levels and, most importantly, pathways for CCE training. ¹¹ The CICM USIG has led applications of ultrasonography during the coronavirus disease 2019 (COVID-19) pandemic. It has held multiple educational, administrative and scientific meetings, and is an established expert advisory group in CCE for CICM. The executive group is now building strong ties with ANZICS and multiple CCE groups and societies around the world. Through this hard work, USIG has earned the professional recognition of the CICM Board, making a major contribution to the development and implementation of the CICM module on basic CCE and the IC-29 CICM policy, ¹² in addition to having current involvement in a major redesign of the ultrasound training curriculum within the College.
 

On the clinical side, two major issues dominated early critical care ultrasonography: availability of adequate equipment and medico-legal compliance. While the early pioneers had great difficulties to persuade administrators to purchase state-of-the-art scanners, thus reserved to work with second-hand ultrasound equipment poached from discarded cardiology stock, a recent CICM USIG survey found wide availability of relatively high level ultrasound equipment for ICUs. ¹³
 

Debate continues as to the role of miniature scanners in intensive care practice. Although several centres have started to integrate hand-held cardiac ultrasound in medical emergency response teams, their success so far has been mixed. Continued technological advancement may well make this subject worthy of further analysis, particularly in view of the recent research from Vienna that successfully explored remote ultrasound supervision. ¹⁴
 

The medico-legal issues centred around local credentialling and archiving of studies. A lack of formal qualifications, standardised training, and variability of pathways to proficiency served as major barriers for intensivists seeking to gain institutional credentialling. The CICM’s endorsement of three levels of training in CCE ended the uncertainty and cemented the pathway of formal recognition for its Fellows. Structured systems of archiving and reporting of echocardiographic studies in ICU appears to work better in places where cardiologists and intensivists work in harmony towards a common goal. Unfortunately, over a third of intensive care units still lack these systems, which are essential from medical, administrative, research and legal perspectives. ¹³ Routine archiving and reporting should no longer be an optional part of the job but should become the Australian Council on Healthcare Standards (ACHS) requirement for hospitals accreditation. Local health authorities must be made aware that it is an integral part of Australian health care standards to guarantee adequate resources in line with the national standards set by the USIG for CCE. Ongoing support by the CICM Board and a wider Fellowship in future integration of quality CCE under the guidance of USIG are essential for long term success.

The gradual adoption of ultrasound imaging other than echocardiography in critically ill patients has evolved over many years, and techniques such as ultrasound-guided line insertion have become the standard of care. Lung, vascular and rapid abdominal investigations using ultrasonography are also entering the mainstream. Coordination of cardiac and non-cardiac ultrasound makes good economic and organisational sense, such as the choice of scanners and archiving systems.
 

While intensive care medicine has positioned itself to take advantage of ongoing ultrasound developments, the task of CCE education remains daunting. Only 5% of all CICM Fellows currently have an advanced level of training in CCE, yet there are 1200 registered CICM trainees who are required to complete basic CCE training and have their competency assessed. It is inevitable the current focus on teaching basic CCE to trainees will be matched by a huge increase in the demand for advanced CCE training, both in TTE and TOE. Dedicated time for trainers is essential; indeed, the proportion of necessary time should be built into every ICU specialist staffing complement and addressed during the regular College’s accreditation visits.
 

Ultrasonography is a repeatable point-of-care diagnostic and monitoring technique with immediate integration of the results in critical care management, thus training ICU practitioners to use it appears most sensible, with outsourcing being impractical. The evolving challenge is to find additional time for the trainees already dealing with a demanding curriculum. Some believe that teaching future intensivists should be limited to a qualitative echocardiography haemodynamic assessment, while others strongly believe that basic quantification skills should be the minimum level of achievement. The latter greatly enhances clinical benefit but requires Doppler ultrasound skills, which take significant extra time and experience to achieve. Either approach demands that dedicated time be put aside for the trainees, something that at present has not been adequately addressed.
 

As mentioned above, the number of advanced critical care echocardiographic practitioners available for education is still suboptimal. Prevention of poor and overconfident ultrasound practice is essential for patients’ safety and for CCE credibility. Therefore, standardised and highly professional assessment is required for all types and levels of training. Would the College itself, the USIG or an outside party have sufficient resources and the expertise? One example of a third party could be ASUM, which already provides avenues for the basic (CCPU) and advanced (DDU) levels of training and assessment. The flip side of such arrangement is the loss of autonomy by intensive care professionals. Perhaps, a hybrid and/or a joint venture could be recommended to offer a most practical solution.
 

There is no doubt that TOE is an essential part of echocardiographic evaluation in many critically ill patients, being complementary to TTE. However, the overall numbers of TOEs performed in any one year in most Australian ICUs is inadequate for all trained practitioners to maintain skills. An individually tailored local solution could include protected clinical time for such intensivists to work with colleagues in cardiac anaesthesia and cardiology departments, performing complex interventional and intraoperative echocardiography.
 

Cooperative ventures with cardiology, anaesthetics and radiology have become more amicable over recent years in many institutions, but sadly remain far from universal. Recent rapid technological advances in minimally invasive valvular and electrophysiological interventions brings these procedures to the ICU bedside. Familiarity and proficiency with new techniques by intensivists experts in CCE can be of great benefit. One of such examples is the recent introduction of intracardiac echocardiography into the armamentarium of expert critical care techniques. ¹⁵ Building interdisciplinary bridges and developing joined interdisciplinary training, education and quality assurance programs allows for energies to be spent on improving both cardiac and critical care echocardiography services and is the most beneficial way forward.
 

Overall, the future for CCE is bright. The wheel of time has turned. Looking over the past 25 years as both participants and observers, we marvel at the transformation of point-of-care ultrasound coming in from a humble outcast status 25–30 years ago to mainstream around the world. The road, although often rough and difficult to traverse, was really never in doubt because the potential of echocardiography in critically ill patients was obvious. The COVID-19 pandemic reinforced cardiopulmonary ultrasound as a centre-stage diagnostic point-of-care modality. We are now being joined by hundreds of similar-minded colleagues, many of whom are looking ahead, pondering what will be the next exciting turn in the history wheel of CCE development.
 

Incredible technological advances are likely to continue in the world of ultrasound, particularly with ongoing miniaturisation of scanners, incorporation of artificial intelligence, and progress in mobile connectivity. It will contribute to new pathophysiological concepts, stimulate new directions in CCE practice and research, and open opportunities for new and better therapies. Would the term “bedside echocardiography” remain synonymous with “basic echocardiography”, or will the state-of-the-art expert TTE, TOE and intracardiac echocardiography techniques brought to the intensive care beds by highly trained CICM Fellows signify the future modern CCE? We do not know the details, but we do know, that it will be a trip worth taking.