Respiratory Care Clinics of North America

2006-12-01

Forthcoming Issues

2006-12-01

Foreword

Richard D. Branson, Neil R. MacIntyre — 2006-12-01

The relationship of pulmonary disease and nutrition is complex and often unappreciated. Both critically ill patients requiring mechanical ventilation and patients with chronic respiratory disease are at risk for malnutrition. This is the one facet of the nutrition–pulmonary disease relationship that seems to be undisputed. Less clear is the importance of nutritional support, including the type of nutritional supplementation and the number of calories to be delivered. Good arguments for both hypocaloric and isocaloric feeding can be made for the critically ill patient, and re-feeding seems to make sense for the malnourished patient with chronic respiratory disease. The patient with cystic fibrosis is a special case with further complexity.

Preface

Ainsley M. Malone — 2006-12-01

The relationship between respiration and nutrition is one of the most basic, from a physiologic standpoint. Oxygen is required for metabolism of nutrients, yielding energy necessary for the organism to perform its work. This relationship and the factors that affect it are most evident in the arena of critical care. The idea to create an issue of the Respiratory Care Clinics of North America on nutrition issues in respiratory care was identified from this important connection. The article “Malnutrition in Chronic Obstructive Pulmonary Disease” provides the framework for recognizing the issues in caring for this population in a critical care setting; “Nutrition Support of the Acutely Ill Ventilated Patient” reviews current practices for managing these patients, while “Nutrition Modulation in the Patient with Acute Respiratory Distress Syndrome” delves into the role nutrition may offer in patients with this complicated disease. Two important topics related to nutrition support management involving the respiratory system include (1) the use of hypocaloric feeding to reduce overfeeding and its subsequent effect on the work of breathing and (2) minimizing the incidence of pulmonary aspiration during enteral nutrition support. These two subjects are detailed in the articles “Hypocaloric Nutrition in the Critically Ill Patient” and “Minimizing Pulmonary Aspiration in Enteral Nutrition Support.” Moving to the arena of the patient who requires chronic respiratory care, “Nutrition Support for the Long-Term Ventilator-Dependent Patient” reviews current issues in caring for this patient population. And finally, an area in which respiratory care and nutrition support practitioners collaborate, indirect calorimetry, is explored by the articles, “Indirect Calorimetry—Applications in Practice” and “Indirect Calorimetry—Relevance to Patient Outcome.”

Malnutrition in Chronic Obstructive Pulmonary Disease

Denise Baird Schwartz — 2006-12-01

Malnutrition is frequently reported in patients with chronic obstructive pulmonary disease (COPD) . Numerous contributing factors have been identified in the development of malnutrition in COPD . Weight loss is a major clinical occurrence with depletion in lean body mass. Poor nutrition status in COPD patients is related to adverse effects that contribute to complications and increase morbidity and mortality. Low body weight in patients with COPD results in decreased lung function and reduced exercise capacity. Complex changes in metabolism occur as a result of inflammation, hypoxia, hypercapnia, nutrition deficits, and pharmacological therapy .

Nutrition Support in the Acutely Ventilated Patient

Mark H. Oltermann — 2006-12-01

Patients who require an artificial airway and a mechanical ventilator are at significant risk for morbidity and mortality in the acute hospital setting. “Acutely ventilated” is arbitrarily defined in this article as the first 2 weeks of ventilator support, a period during which decisions are made about the timing, of nutrition initiation, feeding during inflammatory stress, and attempts to ameliorate subsequent hypermetabolism. Nutritional strategies for long-term ventilated patients will be discussed elsewhere in this volume. Nutritional manipulation, which is the provision of enteral feeding via an artificial tube or a parenteral nutrient mixture through a vein, is a medical intervention and should be viewed just like any other medical decision. Is there a favorable risk/benefit ratio? Inherent risks with nutrition support can be up to 5% or 10%, depending on the skill of the institution and its use of defined protocols. Patients unlikely to benefit from nutrition intervention include those extubated within the first 3 days and able to eat normally at that time. Examples of these lower-risk intubated patients include patients recovering from simple overdoses, patients recovering from routine elective surgical procedures (eg, bypass grafting), some acute asthma patients, and patients with quickly reversible heart failure. Short-term nutrition support is not likely to have a long-term impact on such patients. However, this does not imply that nutrition support should only be initiated 72 hours or more after admit. On the contrary, early enteral nutrition defined as feedings within 24 hours of intensive care unit [ICU] admit, has the potential to interact with the inflammatory cascade. The key is to be able to predict on day one of illness which patients are likely to still be intubated on day three. Aggressive nutrition support protocols may end up providing no benefit to a small percentage of patients. Yet it is the standardized protocols themselves that will also lower the risk of early nutritional manipulation. The “acceptable” percentage of low-risk patients subjected to nutritional manipulation is unstudied, but probably should be <10%.

A Nutritional Strategy to Improve Oxygenation and Decrease Morbidity in Patients Who Have Acute Respiratory Distress Syndrome

Stephen J. DeMichele, Steven M. Wood, Ann K. Wennberg — 2006-12-01

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) occur in both medical and surgical patients. Previously, it was believed that the incidence of ALI and ARDS ranged from 1.5 to 8.3 per 100,00 person years but Rubenfeld and colleagues point out that the incidence of both ALI and ARDS has been significantly underestimated in the United States and may be as much as 2.5 to 40 times higher (56–82 cases per 100,000 person years) . ARDS is manifested by a noncardiogenic pulmonary edema and refractory hypoxemia with widespread inflammation in the lung parenchyma that leads to decreased lung function . Contributing factors that may give rise to ARDS include aspiration, pulmonary contusion, toxic inhalation, pneumonia, shock, multiple fractures, transfusions, burn injury, disseminating intravascular coagulation, pancreatitis, and sepsis .

Nutrition Support for the Long-Term Ventilator-Dependent Patient

Gail Cresci, Jorge I. Cué — 2006-12-01

Acute injury, such as illness or trauma, is associated with neuroendocrine and cytokine responses that activate a cascade of events resulting in what has been termed the systemic inflammatory response. These responses include increases in heart rate, minute ventilation, and metabolism to meet tissue demands for increased oxygen requirements. Following acute injury, a rapid shift occurs from an anabolic state of storing protein, lipid, and glycogen to a catabolic state with mobilization of these nutrients for energy use . The severity of the injury correlates directly with the degree of substrate mobilization. Tissue catabolism is mediated through the release of cytokines, such as tumor necrosis factor; interleukins-1, -2, and -6; and the counterregulatory hormones, such as epinephrine, norepinephrine, glucagon, and cortisol . These hormones are labeled counterregulatory because they oppose the anabolic effects of insulin and other anabolic hormones. Circulating levels of insulin are elevated in most metabolically stressed patients, but the responsiveness of tissues to insulin, especially skeletal muscle, is severely blunted. This relative insulin resistance is believed to be due to the effects of the counterregulatory hormones. The hormonal milieu normalizes only after the injury or metabolic stress has resolved.

Feeding the Critically Ill Obese Patient: The Role of Hypocaloric Nutrition Support

Jerad P. Miller, Patricia Smith Choban — 2006-12-01

Obesity continues to become more common throughout the United States. The most recent National Health and Nutrition Examination Survey indicates that two thirds of adults in the United States are overweight or obese with 32%, or 60 million adults, being defined as obese (body mass index [BMI] >30 kg/m2) . This represents a 16% increase from the previous study period (1988–1994).

Strategies to Prevent Aspiration-related Pneumonia in Tube-fed Patients

Norma A. Metheny — 2006-12-01

Tracheobronchial aspiration of oropharyngeal secretions and refluxed gastric contents is a dreaded complication of tube feedings that can result in significant morbidity and potentially high mortality . It is difficult to determine how often aspiration occurs because clinical studies have lacked a standard definition of this condition . Findings from studies that relied on detecting glucose or dye-stained formula in tracheal secretions are not reliable . Two recent studies that used highly sensitive laboratory assays for aspiration found that most critically ill, mechanically ventilated patients experience micro-aspiration at least once during their early days of tube feedings .

Indirect Calorimetry: Applications in Practice

Jennifer A. Wooley — 2006-12-01

Malnutrition is prevalent in critically ill patients and can be present before admission to the ICU or develop during the course of the patient's critical illness . The role of specialized nutrition support in combating malnutrition in the hospitalized patient is well recognized. Nutritional status is vital to overall immune function and the ability to mount a stress response . The metabolic stress of acute illness superimposed on malnutrition is associated with negative patient outcomes and increased health care costs . Patients who have a negative cumulative energy balance have a higher rate of ventilator dependence, remain in the ICU longer, and experience higher mortality rates than those who have a positive energy balance .

Indirect Calorimetry: Relevance to Patient Outcome

Stephen A. McClave — 2006-12-01

In the era of evidence-based medicine, diagnostic tests and treatment interventions are evaluated for their impact on patient outcome. While this principle is important in directing clinical practice, not all aspects of patient care can be shown to directly change outcome. Optimum medical care for any given patient may require a variety of components that indirectly improve outcome and reduce the likelihood for complications. Such is the case for indirect calorimetry as an adjunctive tool in the management of the patient on specialized nutrition support.

Index

2006-12-01

Instructions for Completing the Examination for Credit

2006-12-01

Respiratory Care Clinics of North America

Contents

Forthcoming Issues

Foreword

Preface

Malnutrition in Chronic Obstructive Pulmonary Disease

Nutrition Support in the Acutely Ventilated Patient

A Nutritional Strategy to Improve Oxygenation and Decrease Morbidity in Patients Who Have Acute Respiratory Distress Syndrome

Nutrition Support for the Long-Term Ventilator-Dependent Patient

Feeding the Critically Ill Obese Patient: The Role of Hypocaloric Nutrition Support

Strategies to Prevent Aspiration-related Pneumonia in Tube-fed Patients

Indirect Calorimetry: Applications in Practice

Indirect Calorimetry: Relevance to Patient Outcome

Index

Instructions for Completing the Examination for Credit