Obesity

Obesity

Studies show that in developed countries, body weight and body mass
index (BMI) tend to increase until the age of 60, at which point they either
remain stable or decrease slowly, from 0 to 0.6 kg/yr [18]. In the elderly,
there is a decrease in daily total energy expenditure secondary to less physical
activity and decreased metabolic rate. Population studies in a 70-yearold
cohort indicate that 18% are obese (BMIR30), and 40% are overweight


(BMI 25–29.9) [18a]. The majority in the obese group were women, whereas
the majority in the overweight group were men. Overweight has not consistently
been found to increase mortality. Visceral adiposity, and not BMI measurements,
may be a better prediction of mortality. But compared with their
normal weight cohorts, those who have a BMI of 25 or greater had substantially
higher rates of diabetes, heart disease, hypertension, and osteoarthritis.
The American Heart Association has upgraded obesity from a contributing
risk factor to a major modifiable risk factor for CHD [19].
Anesthetic implications for the obese elderly may be divided into three
areas: (1) issues such as intravenous access, airway management, and reduced
functional residual capacity that are similar to those for any obese
age group; (2) diseases associated with obesity and their end-organ damage,
especially type 2 diabetes and CHD; and (3) accurate blood pressure measurement.
The threshold for placement of an intra-arterial catheter for accurate
blood pressure measurement should be very low.