EFFECTS OF PHYSIOLOGIC CHANGES
Posted by admin on October 13th, 2008Population norms, but not individual norms, can be established for any physiologic parameter and its laboratory measurement. Yet, variability is the hallmark of aging, and physiologic change is no exception; as a result, extrapolating from norms to individuals is done with less confidence in the elderly. Many normal elderly persons show little or no physiologic decline in organ function, while many others show significant decline. One of the most useful techniques to establish the presence of disease is to compare current laboratory values with results obtained when disease was not present. Of course, this type of comparison is likely to be possible only for routinely performed tests.
Age-associated declines in cardiac, pulmonary, renal, and metabolic function correlate with changes in normal laboratory values (see TABLE 113-2). For example, systolic blood pressure increases, and maximal cardiac output decreases whether measured invasively or noninva-sively. Vital capacity, forced expiratory volume at 1 sec, and maximal breathing capacity decrease progressively with age
