Obesity hypoventilation syndrome is obesity-pulmonary hypoventilation syndrome, also known as obesity cardiopulmonary insufficiency syndrome (Pickwickian syndrome), obesity with cardiopulmonary failure, idiopathic alveolar hypoventilation syndrome, cardiopulmonary-obesity syndrome, obesity-dyspnea-somnia syndrome, narcolepsy with diabetic hyperinsulinemia syndrome, etc. This symptom is common in extremely obese children and is a clinical syndrome of severe obesity. It is related to excessive obesity leading to low ventilation function. It is a type of alveolar hypoventilation syndrome, a special type of cor pulmonale, and a common and serious complication in obese patients. This symptom refers to a series of symptoms caused by poor alveolar ventilation in extremely obese patients without primary heart or lung diseases. If the weight can be reduced, the clinical symptoms can be significantly improved.