[Preoperative assessment of obese patients]

Obesity affects every organ system and causes significant chronic medical co-morbidities. In particular, perioperative hypoxemia is quite common due to a decrease in expiratory reserve volume, and the change increases in direct proportion with increasing body mass index (BMI). To avoid the hypoxemia during induction of general anesthesia, evaluation of difficult airway is very important. Obesity is an important risk factor for obstructive sleep apnea syndrome and patients using nasal CPAP or bi-level positive airway pressure (BiPAP) device at home should be treated in post-anesthesia care unit. Signs of pulmonary hypertension, such as exertional dyspnea, fatigue and syncope, should be sought preoperatively and transesophageal echocardiography obtained in symptomatic patients. Thromboembolism is a major cause of postoperative mortality and anticoagulation or other prophylaxis measures should be started in the preoperative period.