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Preanesthesia medical evaluation of the obese patient

Roman Schumann, MD
Section Editor
Stephanie B Jones, MD
Deputy Editor
Marianna Crowley, MD


As the prevalence of obesity increases worldwide, an increasing number of obese surgical patients will require anesthesia. Planning for anesthesia must take into account both physiologic changes caused by obesity, and the presence of comorbid conditions associated with obesity; consequently, the preanesthetic evaluation should determine and evaluate the relevant issues for the individual patient.

Obesity is typically defined by body mass index (BMI), the ratio of weight (in kilograms) to the square of height (in meters) (calculator 1). In adults, the World Health Organization (WHO) and the National Institutes of Health (NIH) have adopted a classification of obesity defined by BMI:

Overweight – BMI ≥25 to 29.9 kg/m2.

Obesity – BMI ≥30 kg/m2.

Obesity class 1 – BMI of 30 to 34.9 kg/m2.

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Literature review current through: Nov 2017. | This topic last updated: Nov 16, 2016.
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