Challenging and Emerging Conditions in Emergency Medicine

Arvind Venkat

• Publisher: Wiley-Blackwell
• Year: 2011
• ISBN:
  9781119971580
• Edition: 1
• Topic: Medicine
• Subtopic: Emergency Medicine & Critical Care

With growing numbers of chronically ill patients surviving longer and receiving novel medical and surgical treatments, emergency departments are increasingly the venue for associated acute presentations. How can emergency physicians respond to these challenging and emerging conditions?

This book focuses on the unusual and complex disease presentations not covered in detail in the standard textbooks, helping you manage patients with conditions such as congenital heart disease, cystic fibrosis, morbid obesity, intellectual disability and intestinal failure.

Not only does this book provide guidance on evaluation and diagnosis, but it also addresses the practical issues of acute management and continuing referral. The individual chapters are written by high profile emergency physicians, in conjunction with appropriate specialists, and include authoritative evidence to back up the clinical information.

Chapter 1

Introduction

Arvind Venkat

Allegheny General Hospital, Pittsburgh, PA, USA; Drexel University College of Medicine, Philadelphia, PA, USA

The emergency department (ED) serves as the gateway for medical care for the preponderance of acutely ill patients. Whether due to medical, surgical, pediatric, obstetric, neurologic, or psychiatric conditions, patients presenting with acute ailments expect that the ED and emergency physicians in particular will be able to diagnose and initiate management of critical conditions. In the United States, as of 2007, there were 117 million annual visits to the ED with 39.4 visits/100 persons [1]. Worldwide, there has been increasing recognition of the need for quality emergency care and the resultant recognition of emergency medicine as a medical specialty in nations as diverse as India, Turkey, and Malaysia. With this explosive growth in emergency care, it is increasingly common for patients to view the ED as the location for entrance into the health care system when confronted with unexpected and severe medical complaints.

This recognition of the ED is well warranted, but it does create a dilemma for emergency physicians who in their practice must be aware of the vast complexities of ailments that can cause patients to present for emergency care. While emergency physicians are clearly well trained to deal with the most common diseases that require emergency interventions, such as cardiovascular disease and trauma, providers in the ED must now become facile with managing patients whose disease entities are either only now being recognized and treated or whose therapies have only recently been developed. During a typical clinical shift, an emergency physician may have to manage acute issues in patients whose co-morbid illnesses may include transplantation, congenital heart disease, end-stage renal disease or cancer. Without awareness of the new treatments and procedures in these areas as well as the implications of increased longevity in patients who previously may have never required emergency care in the past, it is easily foreseeable that emergency physicians may not correctly diagnose and initiate treatment in conditions that require acute intervention with resultant detriment to the patient.

At the same time, the literature and educational process in emergency medicine has understandably largely focused upon patients who present most commonly for ED care. Research in emergency medicine largely, though not exclusively, focuses on the most prevalent conditions, such as acute coronary syndromes, pulmonary embolism, stroke, trauma, and sepsis, while textbooks in emergency medicine are largely comprehensive surveys of the entire gamut of diseases that can cause presentation to the ED. Similarly, the core curriculum in emergency medicine for residency training in the United States attempts to cover the entire range of conditions to the ED, but in the process does not allow for more in-depth consideration by trainees of patient populations that are either on the horizon or whose therapies are quickly evolving to result in increased longevity and changed pathophysiology.

This book attempts to address this educational need for emergency physicians to understand patient populations whose ailments either are being treated in new ways or to rectify a lack of common recognition both in diagnosis and the implications of increasing longevity. In selecting topics for inclusion, three themes emerge that underline the challenge facing emergency physicians.

Increased longevity

As seen in the chapters on adults with congenital heart disease, the geriatric trauma patient, adults with cystic fibrosis, the intellectually disabled patient, adults with sickle cell disease, and children with intestinal failure, evolving medical care and understanding of the pathophysiology of disease has resulted in a vast improvement in the life expectancy of patients who previously have not survived to adulthood or whose survival to late adulthood has resulted in their exposure to illnesses that will now require ED care. For emergency physicians, this increased longevity will result in the need to reconsider the pathologic processes that can result in illness as well as new complications of late-stage disease. For example, survival to adulthood of patients with congenital heart disease means that emergency physicians will have to recognize the late complications of surgical procedures that were used to correct these defects in infancy as well as the late cardiovascular and pulmonary issues that may not arise until adulthood. The aging of the general population means that emergency physicians will have to understand the more complex pathophysiology of trauma when interacting with other age-related illnesses. Children with intestinal failure may now survive for longer periods of time and present with complications that were only seen in the past in specialized centers shortly after birth. For all the patient populations discussed in these chapters, the underlying theme is that the emergency physicians have to conceive of these patients as surviving well beyond what was previously recognized in day-to-day medical practice and consider how that may cause these individuals to present with novel complications not seen in the past.

Novel treatment modalities

As seen in the chapters on the bariatric surgery patient, HIV-positive adults on highly active antiretroviral therapy, emergency complications of chemotherapeutic regimens, the post-cardiac arrest patient, renal dialysis patients and renal transplant patients, evolving medical and surgical care for patients who previously either had different or ineffective treatment modalities has resulted in emergency complications that require recognition by ED providers. Such treatments have often provided wonderful benefits to these patient populations in terms of quality of life and longevity, but have made the ED the venue in which acute diagnosis of treatment failures or complications will take place. For example, the astronomic growth of bariatric surgical procedures requires emergency physicians to recognize the resultant anatomic and physiological changes that take place post-operatively and the side effects and treatment issues that can arise. The increased longevity of HIV-positive adults on highly active antiretroviral therapy has resulted in completely new disease processes that more commonly affect this patient population. With the development of hypothermia treatment post-cardiac arrest, emergency physicians are being called upon to manage patients previously thought to be neurologically devastated in a novel and potentially life-changing way. For all these patient populations, the underlying theme is that new and evolving therapies have created a novel set of disease processes and treatments with which emergency physicians must become familiar.

Complications of social pathologies and lack of medical resources

As seen in the chapters on conditions causing chronic pain, family violence, and the obese patient, the ED also serves as the “canary in the mine” for pathologies that often extend beyond the medical realm [2]. To some extent, this may be seen as the dark side of the increased recognition of the ED as the gateway to the health care system. As such, emergency physicians now must contend with the consequences of failures in our medical system and complexities that result from the breakdown in family relationships or societal forces well beyond their control. For example, the growth in the number of patients with conditions that cause chronic pain coupled with a lack of medical training in pain management and a shortage of pain management physicians has left the ED as the venue of last resort for patients who require analgesia, perhaps best managed ideally in the outpatient setting. Increased recognition of child abuse and intimate partner violence has imposed a burden on emergency physicians to treat the medical and social dangers imposed by these conditions. The epidemic of obesity has profound implications for the diagnostic assessment and therapeutic management of patients in the ED. Together, these emerging patient populations represent a profound challenge for emergency care in the twenty-first century.

Chapters in this book are structured so that the reader will have an understanding of the epidemiology, procedural interventions, and disease presentation and management in these patient populations in the ED. Each chapter concludes with a section entitled “The next five years” which is meant to provide the reader with a prediction of where these fields will likely evolve in the near future and the implications of those changes for emergency practice. The contributing authors to this book and I hope that the reader will find that this serves as a starting point for consideration in training programs and clinical EDs as to how best to address the numerous challenging and emerging conditions that will cause patients to present for emergency care.

References

1. Niska R, Bhuiya F, Xu J. National Hospital Ambulatory Medical Survey: 2007 emergency department summary. National Health Statistics Reports 2010 Aug 6; 26: 1–32.

2. Venkat A. Health insurance: canary in the mine. Cincinnati Enquirer 2004 Jul 1: C10.

Chapter 2

The post-cardiac arrest patient

Ankur A. Doshi1,2 and Clifton W. Callaway2

1UPMC Presbyterian and Mercy Hospitals, Pittsburgh, PA, USA

2University of Pittsburgh School of Medicine, Pittsburgh, PA, USA

Introduction

Heart disease is the leading cause of death in the industrialized world [1]. Consequently, the presentation of end-stage heart disease—cardiac arrest—is well known to emergency physicians. Similarly, emergency providers, both in the prehospital setting and in the emergency department (ED), are well versed in the treatment algorithms for patients during cardiac arrest. Over the past 35 years, organizations such as the American Heart Association (AHA) and International Liaison Committee on Resuscitation (ILCOR) have developed recommendations for care of patients in cardiac arrest [2,3]. These references, including Advanced Cardiovascular Life Support (ACLS), provide standardized care of patients in cardiac arrest. Even though the baseline characteristics of patients in cardiac arrest are fairly uniform, the rates of survival for these patients still vary geographically [4]. Moreover, from the 1970s through the early 2000s, despite a variety of newly researched and implemented interventions, there was no change in long-term survival of cardiac arrest patients [5--10].

In the past 10 years, scientists have begun to better describe the pathophysiology of cardiac arrest leading to research that has demonstrated that physiologic derangements occur not only during but also after cardiac arrest [11]. Consequently, clinicians have begun to recognize the need to coordinate care of patients during and after cardiac arrest to maximize patients’ survival [11]. In many cases, early, aggressive treatment directed at the specific pathology after cardiac arrest (post-cardiac arrest care) is essential to allow patients the maximum likelihood of beneficial neurological outcomes [11]. This strategy of beginning post-cardiac arrest care promptly is now advocated by guidelines published by the AHA and ILCOR such as ACLS [2,3]. Yet, less than 20% of US emergency physicians have treated patients with post-cardiac arrest care [12]. This chapter outlines the evidence supporting aggressive post-cardiac arrest care in the ED, protocols for performing efficient post-cardiac arrest resuscitation in the acute setting, and future directions in the evolution of care of the post-cardiac arrest patient.

Epidemiology and pathophysiology

An estimated two-thirds of US citizens are at high lifetime predicted risk for atherosclerotic cardiovascular disease [13]. Consequently, cardiovascular disease was the cause of one in six deaths in the United States in 2006 [1]. The end point of cardiovascular disease is sudden cardiac arrest, which most often occurs in the out-of-hospital setting [14]. The incidence of out-of-hospital cardiac arrest is estimated to range from 55 to 120 events per 100,000 persons per year [14,15]. A recent North American sample demonstrated the median incidence of out-of-hospital cardiac arrest to be 52.1 events per 100,000 persons per year. The mean survival in this cohort was 8.4% [4]. As expected, the demographics of cardiac arrest mirror those of other coronary heart disease. The mean age for patients with sudden cardiac arrest is between 65 and 70 years of age, and death from sudden cardiac arrest is more common in men than women [4,14]. Patients with ventricular fibrillation arrests, those who received bystander CPR (cardiopulmonary resuscitation), and those with rapid return of spontaneous circulation, survive at a greater rate than those who do not meet these criteria [11]. However, there is great variability in survival, with some regions of North America reporting overall survival after out-of-hospital cardiac arrest to be greater than 15% and others reporting survival of less than 2% [4]. This variation persists even after controlling for patient and resuscitation variables, such as witnessed collapse, bystander CPR, ambulance response times, and initial rhythm [4]. Part of this variation may be explained by differing ED and in-hospital care [16].

The causes of death for patients after cardiac arrest can be broadly divided into two categories—“cardiac death” and “neurological death.” Cardiac death is due to intrinsic cardiac failure, either the inability to restart spontaneous cardiac contraction or the inability to maintain systemic perfusion after significant myocardial damage. Neurological death is due to accumulated cellular damage to the central nervous system (CNS). Standard care of the cardiac arrest patient prior to 2002 focused only on the restoration of circulation and did not address the continued pathology of cardiac arrest after return of spontaneous circulation [17]. For the past 30 years, despite newer medications and devices to treat out-of-hospital cardiac arrest, only approximately one-third of patients have return of spontaneous circulation long enough to be admitted to the hospital [14]. Almost by definition, patients who do not survive to hospital admission are considered to have cardiac death [11].

Of the out-of-hospital cardiac arrest patients who survive to hospital admission, another two-thirds will die prior to hospital discharge. Although some patients develop secondary cardiac failure or other complications of severe illness, the primary etiology of in-hospital mortality is severe neurological injury [18,19]. The CNS cellular damage in this group is not simply due to ischemic cell necrosis but also due to reperfusion injury. Reperfusion injury is a second wave of cellular damage that is characterized by dysregulation of CNS protective mechanisms and plays out for hours to days after return of spontaneous circulation. Consequently, the previous treatment of cardiac arrest, as limited to the achievement of return of spontaneous circulation, did not address this secondary neurological injury [11]. Although CNS reperfusion injury had been identified for a number of years, until recently, no therapy had been found to minimize its effect. Randomized trials tested treatment such as calcium-channel blockers, benzodiazapines, and even specific antibodies without demonstrating benefit in humans [20--22]. The first successful clinical trials demonstrating successful treatment of CNS reperfusion injury after out-of-hospital cardiac arrest were pub...

Table of contents

• Cover
• Title Page
• Copyright
• List of Contributors
• Acknowledgments
• Chapter 1: Introduction
• Chapter 2: The post-cardiac arrest patient
• Chapter 3: Adults with congenital heart disease
• Chapter 4: The renal transplant patient
• Chapter 5: The end-stage renal disease patient on dialysis
• Chapter 6: Adults with cystic fibrosis
• Chapter 7: Adults with sickle-cell disease: implications of increasing longevity
• Chapter 8: HIV-positive adults on HAART
• Chapter 9: Adults receiving chemotherapeutic regimens
• Chapter 10: The bariatric surgery patient
• Chapter 11: The obese patient
• Chapter 12: The geriatric trauma patient
• Chapter 13: Children with intestinal failure and complications from visceral transplant
• Chapter 14: Family violence
• Chapter 15: The intellectually disabled patient
• Chapter 16: Adults with conditions causing chronic pain
• Index
• Advertisement