The physiologic changes that occur with aging

The elderly critically ill patient requires more intense consideration and observation, because his or her system has become less capable of adapting to external stresses. Table 2 summarizes the major changes in the various systems and considerations for care in the critical care unit. The use of various diagnostic tests to establish organ function is required in the elderly population before medication or treatment regimes are instituted. Tests typically performed on a routine basis include tests of renal function, gastrointestinal motility, and respiratory and cardiac function. Judicious use of these studies is required, including evaluation of the patient's ability to cooperate and comprehend instructions. Clinicians also must consider the impact of past and recent life-style patterns on the aging process. Health care professionals need to develop ways to promote what Rowe and Kahn have termed, "successful aging," and improve their understanding of factors, psychosocial or physiologic, that facilitate resistance to disease and maintenance of autonomy in the elderly population.