A comparative histopathologic evaluation of the effects of three different solutions used for whole bowel irrigation: an experimental study.

PURPOSE: Although whole bowel irrigation (WBI) is a widely used method of bowel preparation in daily surgical practice, almost nothing is known about the histopathologic alterations caused by WBI and whether these differences have any detrimental effect on the outcome of gastrointestinal surgical procedures. Therefore, an experimental study has been conducted to evaluate and compare the effects of WBI with various solutions on the histology of gastrointestinal tract.

METHODS: During the experimental procedures animals were divided into 4 groups consisting of 8 animals each as follows: group A, WBI performed by using isotonic saline solution; group B, WBI performed by using an isoosmolar solution containing polyethylene glycol (PEG); group C, WBI performed by using Lactated Ringer's solution; group D, Animals that were not irrigated but sham operations that were performed served as controls. Four hours after WBI the animals underwent laparotomy and a segment of transverse colon with intact vascular peduncle was prepared. After waiting for 30 minutes, specimens from duodenum, small intestine, large bowel, colonic segment, and liver were obtained from each animal. Histopathologically, all of the specimens were evaluated and graded by 3 parameters including congestion, edema, and inflammation.

RESULTS: Although varying degrees of congestion, edema, and inflammation were encountered from all of the specimens of group A, B, and C, only slight congestion was noted in all specimens of group D. The difference between group D and other groups was statistically very significant (P < .001). When the sections from duodenums of groups were evaluated, the degree of congestion, edema, and inflammation were found to be moderate in group B, mild-moderate in group A, and mild in group C. Histopathologic examinations of specimens of the small, large bowel, and isolated colonic segment showed severe congestion, edema, and inflammation in group A, moderate-mild in group B, and mild in group C. The difference between A and B, A and C, and A and D was statistically significant (P < .01). Although severe congestion was encountered in liver specimens of group A, only mild congestion was encountered in groups B and C (P= .0001). The matched durations of irrigations and total volume of irrigation solutions were found to be not related with the difference in histopathologic findings.

CONCLUSIONS: WBI has induced varying degrees of histopathologic alterations from mild to severe in the rat gastrointestinal tract. Lactated Ringer's solution and PEG solution have induced the least alterations. Therefore, WBI with Lactated Ringer's solution and PEG solution seem to be safe alternatives of mechanical bowel preparation before elective large bowel surgery. Because saline solution has caused detrimental alterations in distal gastrointestinal tract histology, WBI with saline solution seems to be unadvisable.