Organ physiology of aging.

With improvements in medical care over the last several decades, individuals are living longer and, as a result, more surgical procedures will be performed in the geriatric patient. Normal physiologic aging is characterized by a gradual loss of reserve capacity. The effects of the aging process on various organ systems do not usually affect function in the normal state; however, during periods of stress (such as with a surgical procedure or illness), the elderly patient may not be able to meet the increased metabolic demand. This loss of reserve capacity is the single most important factor that decreases the elderly patient's ability to tolerate operations. It is imperative that the surgeon identify the elderly patient who is at increased risk for complications. Specific consideration must be given to proper management of fluid and electrolyte replacement, respiratory management to prevent atelectasis and pneumonia, and monitoring for possible cardiac complications.