THE MEASUREMENT OF VOLUME OF GAS IN THE DIGESTIVE TRACT

Abstract

The gas vol. of the digestive tract is measured in fair approximation by determining its change in vol. during compression by maximal expiratory effort along with its consequent change in pressure, or by determining the changes in vol. with maximal expiratory effort before and after addition of a known vol. of gas. The avg. content of [male] subjects is about 1 1. There are no consistent variations with time of day. Defecation gives no significant reduction. Collection of flatus by rectal tube for 6 consecutive days in 1 subject with army K ration as the principal diet shows daily egestions from as low as 12 up to 340 ml. Another subject collecting all day except during sleep gave values ranging from 200 ml. on normal diet up to 2600 ml. on diets with soy bean for protein. The N2 contents were about 100 ml. and 600 ml., respectively. The exchanges between the gastrointestinal tract and the blood of swallowed air and formed gases are discussed. The conclusion is reached that the vol. of egested flatus is largely dependent on the motility of the gut. When this is high, large amts. of gas are passed with the N2 highly diluted with formed gases but of a relatively large total content which possibly approximates the amt. swallowed. When motility is low, small vols. of gas of high N2 conc. but of low total N2 content are egested. These results indicate that even though swallowed N2 is absorbed slowly, it may be absorbed almost completely.