Gastro-oesophageal sphincter pressure, motility and acid clearing. A study of hiatus hernia patients and normal subjects and of the effect of a modified belsey MK IV repair on the results of the manometric and acid-clearing tests.

Basal gastro-oesophageal sphincter pressure was recorded in 68 patients with symptomatic, radiologically verified sliding hiatus hernia, and in 37 healthy subjects. The diameter of the probe was 2.5 mm, and the flow rate 0.5 ml/min. Mean sphincter pressure was lower in patients (6 mm Hg) than in normal subjects (15 mm Hg). In 32 per cent of the patients sphincter pressure was within normal range (8-24 mm Hg), whereas in 68 per cent it was lower than in the normal subjects. There seemed to be no relationship between sphincter pressure and severity of symptoms. Oesophageal acid clearing was investigated in 57 of the patients and in 26 of the normal subjects. Normal subjects clear the bolus of acid in an average of 10 swallows (range 4-16). In patients the incidence of prolonged clearing was greater, but the acid-clearing ability did not seem to be related to the degree of severity of the symptoms. A manometric study was made of 45 patients and an acid-clearing study made of 40 patients, before and 3 months after a modified Belsey MK IV repair for hiatal hernia. Mean postoperative sphincter pressure was higher (10 mm Hg) than the preoperative mean (6 mm Hg), but was still lower than the normal mean. Significant changes in acid-clearing ability could not be demonstrated. The results are inconclusive with regard to the importance of oesophageal motility disturbances for the symptomatology and acid-clearing ability. Thirty-seven out of 45 patients became free of symptoms, and the rest - except 1 (relapse of hernia) - improved.