Pulmonary Considerations and Management of the Morbidly Obese Patient

Abstract

Morbid obesity, defined as a body mass index (BMI) greater than 40 kg/m 2 has implications for patient morbidity and mortality, hospital length of stay, resource allocation, and cost. Over time, physiologic changes related to morbid obesity occur in all body systems, and are particularly evident in the pulmonary system. Loss of functional residual capacity (FRC), restrictive and obstructive airway patterns, and alterations in gas exchange predispose the morbidly obese patient to conditions such as obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). These conditions contribute to a marked decrease in pulmonary reserve, and when systemic insults such as traumatic injury or illness occur, respiratory failure may develop. Pulmonary anatomy and physiology, including lung capacities, compliance, resistance, and morphological changes that occur over time in the morbidly obese patient, will be discussed. Airway management and mechanical ventilation strategies used in the treatment of acute respiratory failure in the patient with morbid obesity will be reviewed based on current literature and evidence-based guidelines. The role of the nurse as part of the multidisciplinary team in assessing and implementing effective treatment strategies for the morbidly obese patient through the continuum of pulmonary dysfunction will be introduced.