[Effect of mechanical ventilation with different tidal volume on small intestine in dogs suffering from acute lung injury].

Objective: To compare the effect of different tidal volume (VT) on intestinal tissue in oleic acid-induced acute lung injury (ALI) dogs undergoing mechanical ventilation (MV).

Methods: ALI was induced with oleic acid in dogs. While all of them were undergoing MV, they were randomized into two groups: low VT group (n=6), with VT 6 ml/kg, positive end-expiratory pressure (PEEP) 10 cm H2O (1 cm H2O= 0.098 kPa), and large VT group (n=6), with VT 20 ml/kg, PEEP 10 cm H2O. MV with different VT was maintained for 6 hours. After 6 hours, dogs were sacrificed by exsanguination. Pathological changes in small bowel tissues were observed with hematoxylin and eosin (HE) staining, and cellular apoptosis detected with terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) in situ apoptosis determination.

Results: After 6-hour MV, the degree of flatulence was severe in the large VT group, but no flatulence was observed in the low VT group. Bowel injury score was lower in the low VT group than in large VT group [(3.17+/-0.75) scores vs. (2.00+/-0.89) scores]. There was significant difference between two groups (P<0.01). Apoptosis-positive cells were rare in the small bowel tissues in both groups.

Conclusion: MV with large VT can induce bowel dysfunction, in contrast low VT MV does not produce small bowel dysfunction.