Meaning of free intraperitoneal fluid in small-bowel obstruction: preliminary results using high-frequency microsonography in a rat model

OBJECTIVES: The aim of this study was to detect the onset, evolution, and meaning of extraluminal free fluid in a rat model of small-bowel obstruction using high-frequency microsonography. METHODS: Small-bowel obstruction was surgically created in 8 rats divided into 2 groups of 4 rats each. All rats were examined by high-frequency microsonography to monitor the evolution of small-bowel obstruction and the abdominal sonographic findings. In group 2 rats, the obstruction was resolved 2 hours after surgery. RESULTS: In all rats, free peritoneal fluid was detected just near the obstructed loop after 1 hour and in the hepatorenal recess after 2 hours. These features progressively increased in the following hours in group 1 rats. In group 2, the amount of free fluid decreased shortly after removing the obstruction. CONCLUSIONS: Free fluid is an early finding in small-bowel obstruction, and the increase or decrease of its amount is correlated with the worsening or resolution of the obstruction.