Evolution of Critical Care Cardiology: Transformation of the Cardiovascular Intensive Care Unit and the Emerging Need for New Medical Staffing and Training Models

Abstract

HomeCirculationVol. 126, No. 11Evolution of Critical Care Cardiology: Transformation of the Cardiovascular Intensive Care Unit and the Emerging Need for New Medical Staffing and Training Models Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBEvolution of Critical Care Cardiology: Transformation of the Cardiovascular Intensive Care Unit and the Emerging Need for New Medical Staffing and Training ModelsA Scientific Statement From the American Heart Association David A. Morrow, MD, MPH, FAHA, James C. Fang, MD, FAHA, Dan J. Fintel, MD, Christopher B. Granger, MD, FAHA, Jason N. Katz, MD, MHS, Frederick G. Kushner, MD, FAHA, Jeffrey T. Kuvin, MD, Jose Lopez-Sendon, MD, Dorothea McAreavey, MD, Brahmajee Nallamothu, MD, MPH, FAHA, Robert Lee PageII, PharmD, MSPH, FAHA, Joseph E. Parrillo, MD, Pamela N. Peterson, MD, MSPH, FAHA and Chris Winkelman, RN, PhD David A. MorrowDavid A. Morrow Search for more papers by this author , James C. FangJames C. Fang Search for more papers by this author , Dan J. FintelDan J. Fintel Search for more papers by this author , Christopher B. GrangerChristopher B. Granger Search for more papers by this author , Jason N. KatzJason N. Katz Search for more papers by this author , Frederick G. KushnerFrederick G. Kushner Search for more papers by this author , Jeffrey T. KuvinJeffrey T. Kuvin Search for more papers by this author , Jose Lopez-SendonJose Lopez-Sendon Search for more papers by this author , Dorothea McAreaveyDorothea McAreavey Search for more papers by this author , Brahmajee NallamothuBrahmajee Nallamothu Search for more papers by this author , Robert Lee PageIIRobert Lee PageII Search for more papers by this author , Joseph E. ParrilloJoseph E. Parrillo Search for more papers by this author , Pamela N. PetersonPamela N. Peterson Search for more papers by this author and Chris WinkelmanChris Winkelman Search for more papers by this author and on behalf of the American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation, Council on Clinical Cardiology, Council on Cardiovascular Nursing, and Council on Quality of Care and Outcomes Research Originally published14 Aug 2012https://doi.org/10.1161/CIR.0b013e31826890b0Circulation. 2012;126:1408–1428Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2012: Previous Version 1 IntroductionCritical care, defined as the diagnosis and management of life-threatening conditions that require close or constant attention by a group of specially trained health professionals, is inherent to the practice of cardiovascular medicine. The demand for cardiovascular critical care is increasing with the aging of the population and is reflected by trends in the use of critical care in general.1 Between 2000 and 2005, although the total number of hospital beds in the United States declined by 4.2%, the number of critical care beds increased by 6.5% and the annual costs attributed to critical care increased by 44%, representing 13.4% of hospital costs.2 Projections for the next 15 years suggest that the need for critical care will increase markedly in the United States and globally.1,3–5 For example, in Canada, a 57% increase in the need for critical care beds is anticipated during that period.5Concurrent with increases in demand, the medical demographics of general and cardiac critical care have evolved toward a patient population with an increasing number of comorbid medical conditions who require more prolonged and more technologically sophisticated invasive support. As a result, the delivery of critical care is advancing substantially in its complexity. Moreover, accumulating evidence has indicated that outcomes are better when critical care is provided by specially trained providers in a dedicated intensive care unit (ICU).6–9 In the context of this evolution, provision of optimal care in the contemporary cardiac ICU (CICU) presents a different set of challenges and requires an expanded set of skills compared with 10 years ago. Cardiovascular medicine has lagged behind other medical disciplines that have met the “critical care crisis”4 with ICU-focused innovations in organization, training, and quality improvement. Therefore, the American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation, the Council on Clinical Cardiology, the Council on Cardiovascular Nursing, and the Council on Quality of Care and Outcomes Research have sponsored this writing group to formulate a roadmap to meet the changing needs of the population with cardiovascular disease requiring critical care.Evolution of the CICUEarly History of Critical Care CardiologyIn the early 1960s, after the successful implementation of open- and then closed-chest defibrillation10–12 and the introduction of the first continuous electrocardiographic monitoring, the first coronary care units (CCUs) were formed with the premise that rapid identification and termination of peri-infarction arrhythmias could dramatically alter the natural history of acute myocardial infarction (MI).13,14 The earliest CCUs opened almost simultaneously in 1962 in the United States and Europe, providing electrical cardioversion and resuscitation care for patients with MI in a single unit continuously staffed by specially trained personnel. When Desmond Julian, at the time a senior medical registrar of the Royal Infirmary of Edinburgh (Scotland), presented his novel conception of the CCU to the British Thoracic Society in 1961,13 he enumerated 4 basic mandates that have withstood the test of time: (1) Continuous electrocardiographic monitoring linked to alarms, (2) rapidly initiated cardiopulmonary resuscitation and defibrillation, (3) personnel trained to manage specialized equipment within a single unit, and (4) skilled nurses empowered to independently initiate resuscitation. As is the case today, nurses “properly indoctrinated in electrocardiographic pattern recognition, and qualified to intervene skillfully with a pre-rehearsed and well-disciplined repertoire of activities in the event of cardiac arrest” were at the forefront of delivery of care in the early CCU.15 These same principles were described concurrently by Morris Wilburne in an abstract describing a CCU with an “organized program and step-by-step plan of resuscitation” submitted to the American Heart Association annual meeting in 1961.16 In the late 1960s, the next phase of development of the CCU was ushered in by Bernard Lown and colleagues at the Peter Bent Brigham Hospital in Boston, MA, who described a shift from resuscitation at the time of an arrest to monitoring for early signs of clinical change and prevention of a cardiac arrest.15 A precedent for admitting a broader group of patients with suspected acute MI to a dedicated CCU was established, and a rapid proliferation of CCUs throughout industrialized countries ensued.The advent of CCUs was temporally associated with and often credited for a substantial decrease in the in-hospital mortality rate after MI from 30%–40% in the 1950s to 15%–20% in the 1970s.14,17–19 For example, Killip and Kimball, in their landmark article on acute MI management, described a nearly 20% decline in the post-MI mortality rate after implementation of their CCU.17 By 1980, the major cause of death related to MI had shifted from arrhythmias to ventricular failure. New bedside monitoring techniques such as pulmonary artery catheterization and echocardiography allowed evaluation of cardiac performance peri-MI, which led to the characterization of hemodynamic subsets with prognostic and pathophysiological implications for patient management.20 Albeit based on observational data, the available evidence substantiated the vision of Julian and others that meaningful improvements in outcomes could be achieved by management of patients within the specialized environment of the CCU.21–23Evolving Demographics and Emergence of the Contemporary CICUDespite this evidence of a favorable impact of CCUs over their first 2 to 3 decades and the continued decline in case fatality with MI, at least 1 descriptive study has shown negligible subsequent improvements in the overall mortality rate since the 1980s in a major academic CCU.24 The findings from this24 and other studies identified a dramatically changing demographic profile of the patient population in the contemporary CCU. The proportions of the elderly, women, and minorities admitted to the CCU have all increased steadily over the past several decades. Likewise, chronic illnesses, including diabetes mellitus, hypertension, renal dysfunction, and obstructive lung disease, now commonly coexist with cardiovascular illness in today's CCU, which leads to greater case-mix and escalating illness severity.25 Moreover, competitive demand for ICU beds has resulted in triage of lower-risk patients to non-ICU settings. On a broader scale, the aging of the US population, acute and chronic sequelae of nonfatal MI, and a rising frequency of complications of invasive devices have amplified the frequency and morbidity of multiorgan dysfunction during critical illness.26 At the same time, emerging technologies and improved therapeutics have altered the natural history of critical illness in some groups of patients previously considered unsalvageable, thereby increasing the length of stay, risk of iatrogenic complications, and resource consumption.As a result of each of these trends, the medical and procedural issues that determine outcome in the contemporary CCU are often ones that require substantial expertise in general critical care medicine.26 For example, CCUs now appear strikingly similar to general medical and surgical ICUs with respect to patient characteristics, resource utilization, and mortality rates.27 Moreover, overall medical complexity dominates the outcomes of patients in the modern CCU.28 In an analysis of trends over 2 decades of academic CCU care, Katz and colleagues24 observed a marked increase in the prevalence of sepsis and acute renal failure complicating acute and chronic cardiovascular conditions in the CCU. Not surprisingly, this pattern was also associated with an increase in the use of bronchoscopy and renal replacement therapy, along with an increase in the proportion of patients requiring prolonged mechanical ventilation and a relative decrease in the use of cardiovascular procedures (Figure 1).24,25,29 Each of these findings underscores the evolution from the earliest CCUs, focused on the management of acute MI, into the modern CICU, equipped to meet the complex critical care needs of the patient with cardiovascular disease (Figure 2).Download figureDownload PowerPointFigure 1. Temporal trends in discharge diagnoses and critical care procedures within the Duke University Coronary Care Unit from 1989 to 2006. Data from Katz et al.24 STEMI indicates ST-segment–elevation myocardial infarction; NSTEMI, non–ST-segment–elevation myocardial infarction; PCI, percutaneous coronary intervention; and PA, pulmonary artery.Download figureDownload PowerPointFigure 2. Evolution of the cardiac intensive care unit. Advances in technology, medical care, critical care unit organization, and changes in the patient population have contributed to evolution of the contemporary cardiac intensive care unit from a coronary care unit focused on rapid resuscitation to a unit providing comprehensive critical care for patients with cardiovascular diseases. MI indicates myocardial infarction; STEMI, ST-segment–elevation myocardial infarction; ACS, acute coronary syndrome; HTN, hypertension; and CV, cardiovascular.Advanced Technologies and Special Populations in the CICUThe development of new technologies has heavily influenced the practice of critical care in cardiovascular medicine (Figure 2). As a result, physicians in the modern CICU must be experienced in managing the use and complications of advanced medical technologies, including noninvasive and invasive hemodynamic monitoring tools, complex modes of mechanical ventilation, renal replacement therapies, imaging guidance for bedside vascular procedures, methods for induction of therapeutic hypothermia, and mechanical circulatory support. In addition, the growing populations of patients with severe pulmonary hypertension and advanced structural heart disease merit particular consideration in the formulation of a blueprint to meet the expanding needs of the CICU population.Advanced Heart Failure and Mechanical Circulatory SupportAlthough the rate of admissions to the CICU for ST-segment–elevation MI has been decreasing over time, the number of heart failure admissions has been escalating.24,30 Patients with acute heart failure syndromes and end-stage heart failure can now be stabilized emergently with the use of mechanical circulatory support devices and extracorporeal life support. As such, management of severe heart failure by use of advanced pharmacological agents (eg, intravenous inotropes, vasopressors, and vasodilators) and technologies (intra-aortic balloon counterpulsation, percutaneous and surgically implanted ventricular assist devices, extracorporeal membrane oxygenation, and renal replacement therapies) has become a major focus of the CICU and requires a well-coordinated multidisciplinary approach that involves heart failure specialists and CICU staff. Percutaneous support measures are being used with increasing frequency for the management of acute cardiogenic shock and to support high-risk percutaneous interventions and electrophysiology procedures.31,32 Such patients are highly susceptible to progressive critical illness, often develop multiorgan dysfunction, and consume substantial clinical resources. Some large centers have developed specialized “heart failure ICUs” to care for this growing population. Optimal management of this population of patients and the technology itself requires that the providing clinicians are experienced in the appropriate selection of candidates for implantation, the correct use of such devices, and the early recognition or anticipation of complications related to such devices.Therapeutic Hypothermia in Cardiac ArrestThe care of patients with out-of-hospital cardiac arrest has improved significantly since the inception of the early CICU. Since landmark trials demonstrated the benefits of therapeutic hypothermia,33,34 rapid implementation of cooling has been recommended for all eligible patients who remain comatose after successful restoration of spontaneous circulation after ventricular fibrillation or pulseless ventricular tachycardia. Whether cooled invasively or through external methods, the use of induced hypothermia mandates a carefully orchestrated plan with substantial resource requirements. Patients treated with hypothermic techniques commonly require specialized monitoring, prolonged mechanical ventilation, and extended ICU care. From a critical care perspective, those with cardiac arrest are frequently unstable, at risk for end-organ injury, and particularly vulnerable to infectious complications, including severe pneumonia. Prognostication regarding neurological recovery after therapeutic hypothermia has evolved such that longer time may be required to determine a low chance of recovery. Although often challenging, such prognostication is central to medical decision making after rewarming.35 Multidisciplinary clinical collaboration and experienced clinical management are important to improve outcomes for such patients. As therapeutic hypothermia becomes applied more broadly, the evolution of the CICU must anticipate the growing needs of the heterogeneous group of patients with restoration of spontaneous circulation after cardiac arrest.36End-of-Life Care in the CICUAs a consequence of greater disease severity and expanded supportive technologies within the CICU, end-stage disease states have become commonplace. Coordination of end-of-life care, including discussions with patients and families, decision making about deactivation of devices such as internal defibrillators, ethics consultation, pain management, and symptom relief, is now a central part of compassionate care in the CICU.37 Family members consistently emphasize the importance of effective communication in the intensive care environment and most often rank communication above clinical skills when assessing physician quality of care.38,39 Better communication reduces psychological trauma symptoms, depression, and anxiety; shortens ICU length of stay; and improves the experience during terminal care.40,41 Therefore, a focus on family communication during the delivery of critical care is an essential element of best practice in the CICU.41 The CICU staff must also be familiar with options for palliative interventions and services to provide effective transitions in care.Important Trends in Critical Care: Lessons Learned From General Medical and Surgical ICUsSignificant technical, medical, and organizational advances have changed the face of general critical care medicine. The evidence underlying these advances has originated almost entirely from applied research conducted in general medical and surgical ICUs; however, this progress bears lessons vital to the continued maturation of the contemporary CICU and therefore will be discussed in detail in this section before turning back to the CICU in “Roadmap for the Future in Critical Care Cardiology.” In particular, 3 major evidence-based trends in critical care medicine can be identified: (1) A focus on interventions to optimize patient safety, driven by the recognition that ICU-related complications are a major determinant of outcomes; (2) a shift toward staffing models and structures of ICU coverage that place emphasis on involvement of dedicated intensivists, with advanced training and/or experience in critical care; and (3) recognition of the importance of integrated multidisciplinary care with coordinated activities of physicians, nurses, respiratory therapists, pharmacists, nutritionists, social workers, and consultants.Notably, despite the increase in admissions of elderly patients with complicated medical conditions to general ICUs, there has not been an increase in ICU mortality rates, which provides indirect evidence for steady improvement in the quality of ICU care.1,42 Moreover, these improvements in clinical performance, tied to patient safety and quality of care, have been recognized as important not only by ICU personnel and hospitals but also to accrediting and public agencies.43 The evidence supporting each of these trends will be reviewed within this section, with a particular focus on staffing models that have been developed and investigated in the general critical care environment.Patient Safety and Preventive PracticesInfections and other complications of the multitude of invasive methods for monitoring and treatment used routinely in the ICU have attracted substantial attention as potentially preventable causes of morbidity and mortality in patients receiving critical care. Sepsis remains a significant cause of death in the ICU44 and is related to an aging population, indwelling devices such as vascular and urinary catheters, prolonged intubation with mechanical ventilation, and more prevalent immunosuppressive therapy.44–46 Prudent use of invasive devices is essential to reduce sepsis and its attendant morbidity and mortality.47–49 When invasive devices are necessary, experienced operators should use rigorous protocols for sterile catheter placement and maintenance. Such protocols can substantially reduce catheter- and central line–related bloodstream infections (CLABSI or CLABI).50 Other interventions that may reduce ICU-related complications include restrictive blood transfusion strategies,51,52 measures to prevent and contain Clostridium difficile infections, and daily awakening of patients from sedating medications to reduce the duration of both mechanical ventilation and length of stay in the ICU.53Additional improvements in patient safety have become possible through technical advances in noninvasive ICU methods. For example, noninvasive mechanical ventilation has reduced intubation- and ventilator-associated pneumonia (VAP) rates for selected patients with pulmonary edema or hypercarbic respiratory failure.54 Critical care providers are now trained in these and other important techniques, such as ultrasound methods that are now widely used in ICUs to assist in line placement and other percutaneous procedures such as thoracentesis.55,56 Noninvasive methods for hemodynamic assessment continue to be refined.57,58 Lastly, the role of intelligent information systems in the ICU has grown, providing new opportunities for decision support, safety flags, and tools for improved communication and quality improvement.Physician Staffing Patterns and Clinical OutcomesEach of the interventions described in the preceding sections, including procedural practices, noninvasive methods, and safety and communication protocols, contribute to a complexity of the ICU environment that requires experience and expertise. Because of this complexity, organizational and staffing models for the ICU have been a focus of research in critical care medicine. The results of this research have motivated an ongoing global shift in the predominant structure and clinical operations in ICUs to place value on providing an experienced, multidisciplinary team, led by an ICU-based physician skilled in critical care medicine (the “dedicated intensivist”).Open Versus Closed ICUsIn the United States, several organizational models for ICUs exist: Open, semi-open (hybrid), and closed. In an open ICU, patients are admitted or transferred and subsequently managed by their individual physicians, without routine assessment by an intensivist. The admitting attending physician, however, may seek consultation from relevant subspecialists. By comparison, in a closed ICU, an ICU-based physician evaluates all admissions and assumes primary responsibility for all aspects of patient care. In a semi-open ICU, in which the structure lies somewhere between the open and closed models, patients are admitted under the care of a primary attending physician, with ICU-based intensivists available for consultation and comanagement at the discretion of the primary attending physician.In multiple observational studies, compared with open ICUs, closed medical and surgical ICUs have reported lower morbidity and mortality without an increase in resource utilization.59–62 In a rigorously performed meta-analysis of 27 observational studies of critically ill adults and children that compared outcomes in open versus closed ICUs, closed ICUs, which by design provide high-intensity staffing (as discussed in “Intensivist Versus Nonintensivist Coverage”), were associated with reduced hospital and ICU mortality and with reduced use of resources and length of stay.9 The potential influence of unidentified selection or publication biases, as well as confounding factors, such as from temporal changes in mortality, must be considered in these observational studies with principally historical controls. Nevertheless, better outcomes reported in closed ICUs may plausibly be related to the presence of an intensivist directing care, to improved overall consistency of care and collaboration between team members inherent to the closed-unit environment, or to both elements contributing to more sophisticated patient management. In one retrospective study of outcomes in open and closed ICUs simultaneously managed by the same group of faculty intensivists, mortality was lower in the closed system, without a significant increase in cost.63 This finding suggests that the superior outcomes observed in closed ICUs are related to aspects of closed ICU care that are not provided solely by the availability of a consulting intensivist. Some experts have suggested that team care should be adopted as an alternative term to a closed ICU to emphasize the benefits of integrated multidisciplinary care of critically ill patients.64Intensivist Versus Nonintensivist CoverageThe results of more than 10 nonrandomized studies indicate that ICUs managed by intensivists achieve superior clinical outcomes, including reduced length of stay and associated costs,65,66 length of mechanical ventilation,60 and mortality.6–9,61,67,68 In the majority of these studies, high-intensity ICU physician staffing has been defined as mandatory intensivist consultation or a closed ICU and compared with low-intensity staffing, defined as no intensivist or elective intensivist consultation. In a meta-analysis of these studies, high-intensity ICU physician staffing was associated with a 39% lower ICU mortality rate (relative risk, 0.61; 95% confidence interval, 0.50–0.75) and 29% lower hospital mortality (relative risk, 0.71; 95% confidence interval, 0.62–0.82), as well as reduced ICU and hospital length of stay (Figure 3).8Download figureDownload PowerPointFigure 3. Meta-analysis of 13 studies of high-intensity vs low-intensity intensive care unit (ICU) staffing with an outcome measure of ICU mortality. The setting indicates the type of ICU (medical or surgical [Med/Surg]). N denotes the sample size; OR, odds ratio for mortality with high-intensity vs low-intensity staffing; L95, lower 95% confidence interval; and U95, upper 95% confidence interval. Data are from Pronovost et al9 with permission of the publisher; individual citations for each study are provided in that reference. Copyright © 2002, American Medical Association. All rights reserved.Limitations to this evidence should be recognized. The majority of studies of ICU staffing models were conducted >10 years ago, were relatively small in size, and had nonrandomized designs. In addition, in one analysis of a large administrative data base of ICU patients, hospital mortality was actually higher for patients managed by intensivists.69 However, in that study, the majority of the ICUs included were open units with elective intensivist consultation.70 For these reasons, multicenter, well-controlled (such as cluster-randomized) outcome studies would be valuable to rigorously test the hypothesis that intensivist-based ICU care confers both a survival benefit and economic savings.71 Other studies would also be useful to tease out the multiple factors that influence ICU outcomes and costs, including severity of illness, divergent therapeutic approaches, increasing physician workload,72 and patient insurance status.73Despite the limitations to these data, the overall consistency of the available evidence and the rational basis for improved outcomes with enhanced experience, which is a central tenet of medical and procedural training, are compelling. Intensivists may improve outcomes through common practices, provision of urgent therapy, familiarity with acute conditions usually seen only in the critical care setting, facilitation of multidisciplinary care, increased use of evidence-based measures for prevention of complications, and provision of an ICU leadership role.7,71,74,75 Intensivists are more likely to implement newer care technologies76 and routinely introduce basic improvements, such as a reduction in use of central lines50 or use of simple and effective checklists.77 Lengthy ICU stays have been associated with lack of access to an intensivist.78 Taken together, there is a strong rationale for systems that are built on a pivotal role for dedicated intensivists.Twenty-Four-Hour In-House Intensivist CoverageIn the United States, intensivists have traditionally provided ICU coverage during daytime business hours, with an estimated availability of intensivist care during night hours of ≈10% of ICUs.79 Many critically ill patients are admitted to ICUs during off hours, and if proper and rapid therapy is delivered, mortality may be similar to daytime admissions.80–82 However, some studies suggest that patients admitted to the ICU during off hours have higher mortality even after adjustment for severity of illness.83–87 This evidence has led to consideration of continuous (“24/7”) intensivist care. At least 4 observational studies report that introduction of 24-hour in-hospital intensivist coverage of the ICU was associated with lower mortality,88–90 fewer complications, and reduced hospital length of stay.91,92Although nocturnal intensivist coverage has been associated with shorter hospital length of stay and lower overall cost for the sickest patients, this may not necessarily be the case for less severely ill patients.93 Some experts have argued that 24/7 (24 hours per day, 7 days per week) intensivist staffing itself does not reduce mortality or length of stay.71 A number of factors could account for the differences in mortality rates seen when times of ICU admission are compared, such as differences in illness severity for patients admitted at night and general system issues such as lower levels of medical, nursing, and administrative staffing during off hours.86,90One study raised the hypothesis that the presence of training programs in many academic centers may adversely impact care94 and that 24/7 attending physician oversight may prove advantageous. Another benefit is that the intensivist can continue to educate residents during evening hours. Such new educational opportunities may become especially valuable as resident duty hours are restricted or further reduced.95 However, 24-hour in-hospital intensivist coverage has been reported to reduce job satisfaction and produce “burnout” in a manner that is correlated with the increased numbe