Geriatrics

Numerous studies have documented the importance of advanced age to perioperative risk (see Chapter 62 ). In many of the original studies on factors associated with perioperative mortality, the highest rates of death after surgery occurred among the youngest and the oldest patients. Age was implicated as one of the factors in the risk indices developed by Goldman, Detsky, and Pedersen. Age is predominantly analyzed as a dichotomous variable, with many studies focusing on age greater than 70 years.

One of the issues regarding the mortality rate in the geriatric population is the definition of this group. Multiple definitions have been used for advanced age, including patients older than 65, 70, 80, or 90 years. Denney and Denson^[153] evaluated risk of surgery in patients older than 90 years. They suggested that the prevailing philosophy in 1972—that surgery might not be appropriate in this cohort considering the high perioperative risk—was without objective supporting data. They reported 272 patients undergoing 301 operations at the University of Southern California Medical Center and found, contrary to their expectation, that the risk was more than justified in at least 70% of the nonagenarians. They reported that serious bowel obstruction was the only underlying comorbidity associated with a prohibitive perioperative mortality rate (63%).

Djokovic and Hedley-Whyte^[154] studied outcome after surgery in 500 patients older than 80 years at the Harvard Medical System. They found that mortality was predicted by ASA physical status classification, with greater comorbidity associated with increasing risk. Myocardial infarction was the leading cause of postoperative death. Patients without significant comorbidities (ASA class I) had a mortality rate of less than 1%. The data suggest that surgery is safe in this cohort and that risk is not a function of age but of coexisting disease.

Del Guercio and Cohn^[155] investigated the value of preoperative invasive monitoring in obtaining hemodynamic and cardiopulmonary variables for predicting operative risk in the elderly. A total of 148 consecutive patients older than 65 years were studied preoperatively in an ICU. Only 13.5% had normal physiologic measurements. Advanced and uncorrectable functional deficits were found in 63% of patients, and all of those who underwent the planned operation died. This further supports the contention that coexisting disease, not age, is the risk.

The elderly patient presents a difficult issue for the anesthesiologist. Atherosclerosis increases with advancing age, and the heart muscle itself ages. Further preoperative evaluation in the elderly usually focuses on the identification of comorbidity. Based on the accumulating evidence, it is these factors that influence perioperative risk.