Anesthesia-induced atelectasis is a well-known entity observed in approximately 68-100% of pediatric patients undergoing general anesthesia. The collapse of dependent lung zones starts with anesthesia induction but can persist for hours or even days after surgery. Such anesthesia-related atelectasis has a number of negative clinical consequences such as the impairment of arterial blood oxygenation and lung mechanics as well as the predisposition for ventilator-associated lung injury. The adjustment of ventilator settings for preventing the occurrence of atelectasis and for reducing pulmonary complications remains controversial.