Page 1837 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1306 PART 11: Special Problems in Critical Care

40

Overweight
30

Percent 20

Obese

10

Extremely obese
0
1960-1962 1971-1974 1976-1980 1988-1994 1999-2000 2007-2008
2003-2004
Years
Note: Age-adjusted by the direct method to the year 2000 U.S. Census bureau estimates, using the age groups 20-39, 40-59,
and 60-74 years. Pregnant females were excluded. Overweight is defined as a body mass index (BMI) of 25 or greater but
less than 30; obesity is a BMI greater than or equal to 30; extreme obesity is a BMI greater than or equal to 40.
FIGURE 130-1. Trends in overweight, obesity, and extreme obesity among adults aged 20 to 74 years: United States, 1960-2008. (Accessed from http://www.cdc.gov/nchs/data/hestat/
obesity_adult_07_08/obesity_adult_07_08.htm on 3/2/11. In the public domain. Confirmed with NCHSED [CDC].).

and ethnic differences in the prevalence of overweight and obesity, with PHYSIOLOGIC EFFECTS OF EXTREME OBESITY
the highest rates occurring in non-Hispanic black women and Mexican
American women. Of greatest concern is the high prevalence of obesity Obesity is associated with a reduced life expectancy, particularly in the
9
in children and adolescents. 2 extremely obese. Obesity is associated with cardiovascular disease, dia-
The obesity epidemic is the result of an interaction between genetics betes, sleep apnea, lung disease, liver and gallbladder disease, chronic
and what has been called the “obesigenic” environment. Technologic kidney disease, and cancer. This section summarizes some of these
advances have decreased the cost of food production, thereby making physiologic derangements, with an emphasis on those germane to the
food more affordable, and decreased the energy expended by the typical care of the extremely obese critically ill patient (Table 130-1).
such as watching television or using the computer. Television viewing is ■ CARDIOVASCULAR EFFECTS
worker. Leisure time is increasingly dominated by sedentary activities
3
associated with increased food intake and a decrease in metabolic rate Increases in BMI above 25 kg/m are associated with progressive increases
2
even when compared with other sedentary activities such as reading in the risk of death from ischemic heart disease, stroke, and other vascu-
or sewing. The risks of obesity and type II diabetes mellitus have been lar diseases, the latter category including heart failure and hypertensive
4
positively correlated with the amount of television watched, and children disease. Obesity promotes cardiovascular disease through a variety of
5
9
randomized to an intervention discouraging television viewing had sig-
nificant reductions in relative BMI compared with controls. Relatively
6
recent data suggest that long-term societal reductions in sleep quantity
may play a role in the obesity epidemic. A number of studies performed in TABLE 130-1 Critical Care Considerations in the Extremely Obese Patient
young adults indicate that short-term sleep curtailment is associated with Cardiovascular
decreased insulin sensitivity and glucose tolerance, elevated sympathova- Systolic dysfunction may be due to ischemic heart disease, longstanding
gal balance, increased levels of the hunger-promoting hormone ghrelin, hypertension, or obesity-related cardiomyopathy
decreased levels of the satiety hormone leptin, and increased hunger. In Diastolic dysfunction is common and may be difficult to diagnose
7
addition, studies performed in mice suggest that exposure to low levels of Moderate to severe pulmonary hypertension should prompt consideration of OHS, the
light at night—for instance, in the form of indoor lighting and exposure overlap syndrome, and/or left heart failure
to television and personal electronic devices—may promote obesity by Pulmonary
disrupting the timing of food intake. Other possible explanations for the Reduced pulmonary reserve places patient at risk for respiratory failure from
8
obesity epidemic include an increased percentage of meals eaten outside seemingly trivial insults
the home, the serving of larger portions at commercial establishments, Increased risk of atelectasis, particularly when bed-bound and in postoperative setting
and the widespread consumption of diets low in vegetables and fibers Increased risk of venous thromboembolism
and high in refined sugars. Individual susceptibility to these influences is Sleep disordered breathing
poorly understood but likely includes a genetic component. Untreated OSA may complicate the postoperative course
Unfortunately, the obesity epidemic is not confined to highly developed Untreated sleep disordered breathing may lead to cardiopulmonary failure
countries. The World Health Organization estimates that 1 billion people Patients with inadequately treated OSA and/or the OHS may be particularly sensitive
worldwide are overweight or obese. Worse, while there is some evidence to the effects of sedatives and narcotics
that increases in obesity prevalence may be plateauing in the United States,
most indications are that the worldwide epidemic has not yet peaked. Other concerns
Obesity is increasing in prevalence in developing countries coincident Increased risk of developing intraabdominal hypertension
with decreased physical activity and the replacement of traditional fruits Chronic kidney disease
and whole grains in the diet with calorie-dense, processed foods. Altered pharmacokinetics

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