Gastric emptying of a liquid meal in experimental chemical pneumonitis

Gastric emptying of a liquid test meal was studied in an experimental model of chemical pneumonitis. In the first phase, 160 microliters of a hydrocarbon mixture was injected iv into 10 young adult rats, and the same volume of saline solution was injected into 10 controls. Arterial blood gases and lung dry and wet weight were determined. In the second phase, gastric emptying of a 5% (w/v) glucose solution marked with phenol red (6 mg/dl) was studied 5, 10, 20 and 30 min after orogastric infusion of the test meal. Gastric retention was determined by measuring the concentration of the marker in the residual test meal recovered from the stomach after killing the animal. Thirty-two experimental and 32 control animals were paired and eight pairs were used at each time. The wet weight and external volume of the lungs were determined in all animals and 20 experimental animals were analyzed histopathologically. The animals of the experimental group developed intense macro- and microscopic pulmonary alterations. PaO2 values (mean +/- SD) at the first (70.7 +/- 5.9 mmHg) and fifth hour (71.1 +/- 8.5 mmHg) were significantly lower than the respective values obtained for the control group (109.5 +/- 13.5 and 113.9 +/- 11.2 mmHg). Gastric retention at 5, 10, 20 and 30 min was significantly higher in animals with pneumonitis (median: 59.1%, 55.4%, 45.3%, 27.2%) when compared to respective values for the control group (median: 47.5%, 46.6%, 24.1%, 19.3%). These results indicate a delay in the gastric emptying of liquids in serious pulmonary disorders.(ABSTRACT TRUNCATED AT 250 WORDS)