Respiratory function in esophageal hiatus hernia. I. Spirometry, gas distribution, and arterial blood gases.

As a part of a preoperative investigation, spirometry and blood gas tensions were studied in 64 subjects with X-ray-verified hiatus hernia (34 sliding, 22 mixed, and 8 of paraesophageal variety). According to the transverse diameter of the hernia. They were divided into 3 groups, small (2-5.9 cm), medium (6-9.9 cm), and large (10-17 cm) hernias. No correlation between the size of the hernia, reflux incidence, and spirometric findings could be demonstrated. A significant reduction of the arterial oxygen tension was found in small hernias and in vital capacity and maximal voluntary ventilation (MVV) in medium-sized hernias. Significant reduction in MVV was noted in the large hernia group. A common spirometric finding in all groups was a significant increase in residual volume and wash-out volume. The incidence of restrictive or obstructive pulmonary impairment was high in large (39%) and small (32%) hernias and relatively low in medium-sized hernias (8%). Roentgenological fibrosis was not found in any of the patients, while 4 showed emphysematous changes.