Infantile hypertrophic pyloric stenosis (IHPS) is a condition in which the muscular distal opening of the stomach (i.e., pylorus) is thickened (i.e., hypertrophied) that occurs in young infants. The hypertrophy causes an obstruction with dysfunction of gastric emptying, leading to accumulation of food in the stomach and subsequently to (projectile) vomiting. Persistent emesis can lead to a severe loss of fluids, acids, and electrolytes, resulting in dehydration and metabolic alkalosis. Infants with IHPS are treated by open or laparoscopic pyloromyotomy to dissolve the obstruction. However, it is important to correct dehydration and metabolic abnormalities before administrating anesthesia, as metabolic alkalosis can affect the central regulation of ventilation and respiratory drive, leading to perioperative respiratory events.This thesis comprises a variety of studies regarding IHPS, to improve our knowledge about IHPS and to optimize the perioperative care. We especially focused on the risk of respiratory events in infants undergoing pyloromyotomy and analyzed the association between the occurrence of respiratory events and metabolic alkalosis. Furthermore, we conducted studies regarding the incidence and diagnosis of IHPS and surgical complications of pyloromyotomy. After discussing our results we made several recommendations on diagnosis, correction of metabolic abnormalities, and respiratory monitoring to improve perioperative care for infants with IHPS and reduce the risk of complications
