Critical Illness in the Elderly: Review of Pathophysiology of Aging and Outcome of Intensive Care

Abstract

The goal of this article is to review the literature on age and its influence on the pathophysiology of critical illness, outcome after critical illness, and end of life decision making in critically ill elderly patients. Sources for this review included the MEDLINE database and bibliographies of original articles, reviews, and book chapters. The population is aging and the need for medical care and its costs increase with increasing age. A majority of the elderly lead independent lives, although some need help with various functional activities related to daily living. It is difficult to separate the effects of aging from the effects of the comorbidities that develop with increasing age. The physiologic reserve decreases in the elderly and they may not be able to tolerate a critical injury or illness as well as a younger individual. As the elderlyare usually on multiple medications, they are prone to have more drug interactions and side effects, and need close monitoring of the drugs and adjustment of the dosage. Mortality after a critical illness in the elderly is higher compared to younger patients, and it is more related to the acuity of physiologic disturbance than age alone. The effect of age alone on long-term outcome is not well studied, but individuals with poor functional status and/or increased comorbidities have a poor short-term outcome. Functional status usually deteriorates after critical illness, but the long-term survivors usually recover functional abilities, and they are satisfied with their quality of life. Decision making at the end of life is difficult because of the paucity of data on long-term mortality and quality of life, lack of information about patient wishes, and the uncertainty of the prognosis. Because many elderly patients survive critical illness and may return to their previous lifestyle, age alone should not weigh heavily in end of life decisions. As with other age groups, end of life decisions in the elderly should be made after considering long-term outcomes, patient goals, and the benefits and burdens of life-sustaining technology.