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Bariatric surgery is an option to facilitate weight loss for select patients with obesity. Current guidelines for patient selection include BMI > 40 kg/m2 or ≥ 35 kg/m2 with comorbid disease states (e.g., hypertension and obstructive sleep apnea). Although bariatric procedures have plateaued in the United States, morbid obesity (>40–44.9 kg/m2) rates continue to increase. Important clinical advances in bariatric surgery include the expansion of operative techniques (laparoscopy), improved safety outcomes, and reversal of comorbidities. Many academic centers also offer bariatric procedures in the obese adolescent population (<20 years) as youth obesity rates continue to climb. Unfortunately, these patients have an increased risk of becoming obese adults. Evidence suggests approximately 30% of overweight US adolescents meet the criteria for metabolic syndrome which increases the risk for coronary heart disease and noninsulin-dependent diabetes.
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PREANESTHETIC EVALUATION AND MANAGEMENT
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Because obesity may be associated with a myriad of comorbid disease states, thorough preoperative evaluation prior to anesthesia and surgery is highly recommended. Most bariatric centers have multidisciplinary preoperative clinics which afford an in-person evaluation prior to the time of surgery. Preoperative considerations should be extensive and may include screening for the following pathologies:
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HEENT—Evaluation should check for redundancy of oral mucosa, increased neck circumference (a predictor of difficult intubation), limited cervical spine range of motion, and shortened thyromental distance.
Cardiac—Hypertension and hypercholesterolemia are common and may correlate with ischemic heart disease. Consider cardiology consultation for morbid or extreme obesity with emphasis on baseline cardiac function. Assessment of vascular access options is also helpful.
Pulmonary—Obstructive sleep apnea (OSA) is probable. Closed claimed US data ranks obesity and/or OSA at the time of induction or extubation as culprits for airway management difficulties. Obesity hypoventilation syndrome requires sleep study and/or cardiac echocardiography for a suspicion of pulmonary hypertension. Preoperative counseling for smoking cessation (as long as 8 weeks) should be discussed.
Gastrointestinal—Likelihood of gastrointestinal reflux and aspiration is increased. Consider antiacid preparations prior to induction of anesthesia. Nonalcoholic steatohepatitis (NASH) may influence transaminase levels.
Endocrine—Glucose tolerance must be assessed. Metabolic syndrome—a combination of central obesity, hypertension, hyperinsulinemia, and high triglycerides—may widen the perioperative morbidity profile.
Heme—A history of thrombophilia (deep venous thrombosis and pulmonary embolism) is predictive of adverse outcomes.
Renal—Screen for preexisting vitamin deficiencies (B12, iron, calcium, folate), especially in repeat bariatric surgery patients. Chronic vitamin K (vit K) deficiency may reveal a prolonged prothrombin time. Vitamin K replacement versus fresh frozen plasma transfusion depends upon the timing of surgery.
Integument—Special attention to skin breakdown and pressure sores.
Neurologic—Assessment and scoring for abdominal and joint pain. Psuedo-tumor cerebri is common in females aged 20–45.
Psychologic—Patients are usually required to have a psychological assessment prior to surgery.
Other—Discussion of general anesthesia including the method of endotracheal intubation, possibility of invasive monitoring, and perioperative course (continuation of chronic medications, etc).