An analysis of the factors which may predispose towards postoperative vomiting after pyloromyotomy for hypertrophic pyloric stenosis was carried out in 72 infants at this hospital. 26 (36%) infants experienced moderate to severe postoperative vomiting of sufficient intensity to cause the postoperative feeding regimen to be modified or interrupted. Only two parameters were found to be of statistical significance. These were the state of the oesophageal mucous membrane on endoscopical examination and the presence of haematemesis in the preoperative period. No evidence for a gastric mucosal lesion could be found. An advanced oesophageal mucosal lesion was found in 30% of patients, and this was the source of the haemorrhage in all 11 in whom haematemesis was noted preoperatively. The stay in hospital was prolonged (8 days) in those infants with troublesome vomiting postoperatively compared with those with lesser problems (3 days).
