Longnecker's Anesthesiology > Part 2. Preparing for Anesthesia > Section B. Preoperative Evaluation of the Anesthesia Patient > Chapter 22. Evaluation of the Obese Patient Babatunde O. Ogunnaike, MD, and Charles W. Whitten, MD

Key Points

"1. Expiratory reserve volume is the most sensitive indicator of the effect of obesity on pulmonary function testing.

2. Obesity is an independent risk factor for ischemic heart disease and eventual heart failure. Cardiovascular disease is strongly associated with central (android) distribution of fat. Angina may actually be a direct symptom of obesity because a significant number of obese patients with angina do not have demonstrable coronary artery disease.

3. Plasminogen activator inhibitor-1 (PAI-1), which is secreted by the endothelium, vascular smooth muscle cells, hepatocytes, and adipocytes is associated with visceral obesity and inhibits the fibrinolytic system. PAI-1 decreases fibrinolysis and increases the risk of coronary artery disease.

4. Gastric emptying is delayed in obese patients because of increased abdominal mass that causes antral distension, gastrin release, and a decrease in pH with parietal cell hypersecretion. However, emptying has been documented to be faster with high-energy-content intake such as fat emulsions, but residual volume is increased because of their larger gastric volume (up to 75% larger).

5. Rhabdomyolysis has been documented in morbidly obese patients undergoing prolonged procedures. Elevations in serum creatinine and creatine phosphokinase levels unexplained by other reasons and complaints of buttock, hip, or shoulder pain in the postoperative..."