Severe Pneumonia PDF

Preface

Pneumonia is the number one cause of death from infectious diseases in the United States and can arise both in the hospital as well as in the community. When patients enter the intensive care unit with pneumonia, they have the most severe form of the illness, and the factors that lead to development of severe pneumonia, the optimal management of this disease, and the efforts that can be made to control and improve outcomes in this disease are of great importance to the practicing physician. The aim of this book is to outline the problems associated with the pathogenesis of severe pneumonia and to use these basic principles to guide effective management.

At the current time when patients develop pneumonia, it is sometimes uncertain when they cross the line into severe illness and will benefit from admission to the intensive care unit. This book explores the prospective clinical definition of severe pneumonia, including patients with communityacquired pneumonia, nosocomial pneumonia, and ventilator-associated pneumonia. The bacteriology of severe pneumonia is not, in many instances, very different from that of less severe forms of pneumonia and, therefore, the host inflammatory response to infection is a key determinant of whether or not patients develop severe illness. The cytokine response to infection is discussed along with the reasons why patients with pneumonia progress to severe illness. When patients develop pneumonia during mechanical ventilation, there are a number of pathogenic factors including their underlying chronic illness as well as the mechanical ventilator itself. The role of the ventilator in pneumonia pathogenesis is becoming clear, particularly since noninvasive mechanical ventilation can prevent pneumonia. Therefore, we explore the role of mechanical ventilation in the pathogenesis of this illness.

In an effort to better understand how to optimally manage patients with severe community-acquired pneumonia, it is necessary to look at prognostic scoring systems that identify risk factors for death as well as specific patient features associated with a higher risk of severe illness. These factors are explored and the practical utility of scoring systems for patient managements is discussed. Ultimately, however, to improve the outcome in severe community-acquired pneumonia, it is necessary to anticipate the likely bacteriology and to craft an empiric therapy regimen that covers all likely etiologic pathogens. Both the bacteriology and regimens for empiric therapy are evaluated and examined.

When pneumonia arises during mechanical ventilation, patients are at great risk for mortality, and, in fact, ventilator-associated pneumonia is the leading cause of death from nosocomial infection in the intensive care unit. In this book we examine the risk factors and frequency of ventilator-associated pneumonia as well as the mortality implications of this disease and the factors associated with attributable mortality from ventilator-associated pneumonia. Although it is possible to define the clinical consequences of pneumonia, there remains great controversy about how to diagnose pneumonia and whether it could be diagnosed by clinical means alone or if specific invasive methods with microbiologic cultures should be used. The answers to these questions remain elusive and both sides of this controversy are presented.

To deal effectively with patients who have ventilator-associated pneumonia, it is necessary to choose appropriate antibiotic therapy. Effective choice is limited to some extent by the increasing frequency of antibiotic resistance in the intensive care unit. Therefore, we examine the mechanisms of antibiotic resistance in the intensive care unit and ask how knowledge of antibiotic resistance can be used to achieve optimal and adequate antibiotic therapy. This involves not only knowledge of microbiology and choices of therapy, but also an understanding of the role of microbiologic surveillance. Also, when choosing antibiotic therapy, it is not always enough to choose the right antibiotic, but it is also necessary to choose the appropriate dose and dosing regimen. The science of pharmacokinetics and pharmacodynamics is evolving and the principles associated with this discipline can be used to help with antibiotic choices in the intensive care unit. Specifically, an understanding of pharmacokinetics and pharmacodynamics can help explain the controversies surrounding the use of mono versus combination therapy for the management of ventilator-associated pneumonia.

The future in managing and preventing severe pneumonia is bright and a number of preventive strategies are being developed. These preventive strategies are examined along with new ideas for diagnosis and management that are still in the developmental stage.

I hope that through this book the reader will gain a better appreciation of the pathogenesis, bacteriology, and important clinical features associated with severe pneumonia. Only through an understanding of these complex features will more effective management and prevention become possible, which is our true hope for the future.