Effect of venous strangulation obstruction on length of equine jejunum and relevance to small-intestinal resection.

OBJECTIVE

To determine if venous strangulation obstruction (VSO) of the distal half of the equine small intestine would increase length of that segment.

STUDY DESIGN

Halothane-anesthetized horses were assigned randomly to 3 groups of 5 horses: Group 1 (controls)--the entire small intestine was measured and rubber-shod clamps were applied to mark each end of the most distal 50% of the small intestine; Group 2--same procedure, except that VSO was induced in the distal 50% of the small intestine for 180 minutes; and Group 3--same initial procedure, except that VSO was induced for 90 minutes and followed by reperfusion for 90 minutes.

ANIMALS OR SAMPLE POPULATION

Fifteen horses.

METHODS

The proximal and distal halves of the small intestine were measured before and at 180 minutes after clamps and ligatures were applied. At the end of the study, biopsies were taken to assess mucosal epithelial damage by light microscopy, and horses were euthanatized while under general anesthesia.

RESULTS

Intestine subjected to VSO and VSO and reperfusion had marked hemorrhagic changes and thickening in the intestinal wall. Both groups had incurred a grade 2.8 of 5 mucosal injury by 180 minutes. Total length of small intestine and length of the distal 50% did not change in the control group, but intestine subjected to VSO only and VSO and reperfusion had increased in length by 29% (P <.05) and 36% (P <.05), respectively.

CONCLUSIONS

Small intestine of horses subjected to VSO can increase in length, and this change could cause an overestimate of the amount of intestine involved in an extensive strangulating lesion.

CLINICAL RELEVANCE

An overestimate of the amount of intestine involved in an extensive strangulating lesion could lead to an overly pessimistic assessment of a horse's risk for postresection malabsorption and maldigestion. Therefore, estimates of the proportion of small intestine that is strangulated should be corrected for this potential error and the risk of malabsorption determined accordingly.