Published online May 14, 2018. doi: 10.3748/wjg.v24.i18.2009
Peer-review started: March 10, 2018
First decision: April 11, 2018
Revised: April 20, 2018
Accepted: April 23, 2018
Article in press: April 23, 2018
Published online: May 14, 2018
To investigate viability assessment of segmental small bowel ischemia/reperfusion in a porcine model.
In 15 pigs, five or six 30-cm segments of jejunum were simultaneously made ischemic by clamping the mesenteric arteries and veins for 1 to 16 h. Reperfusion was initiated after different intervals of ischemia (1-8 h) and subsequently monitored for 5-15 h. The intestinal segments were regularly photographed and assessed visually and by palpation. Intraluminal lactate and glycerol concentrations were measured by microdialysis, and samples were collected for light microscopy and transmission electron microscopy. The histological changes were described and graded.
Using light microscopy, the jejunum was considered as viable until 6 h of ischemia, while with transmission electron microscopy the ischemic muscularis propria was considered viable until 5 h of ischemia. However, following ≥ 1 h of reperfusion, only segments that had been ischemic for ≤ 3 h appeared viable, suggesting a possible upper limit for viability in the porcine mesenteric occlusion model. Although intraluminal microdialysis allowed us to closely monitor the onset and duration of ischemia and the onset of reperfusion, we were unable to find sufficient level of association between tissue viability and metabolic markers to conclude that microdialysis is clinically relevant for viability assessment. Evaluation of color and motility appears to be poor indicators of intestinal viability.
Three hours of total ischemia of the small bowel followed by reperfusion appears to be the upper limit for viability in this porcine mesenteric ischemia model.
Core tip: Research on experimental methods to improve the surgeon’s assessment of viability of ischemic bowel with higher accuracy than currently possible, requires an accurate reference model. We investigated viability assessment in a porcine model of warm ischemia on jejunum with mesenteric occlusion, followed by reperfusion. Our aim was to determine the time point of irreversible damage, to provide a reference model. We created parallel segmental models on the jejunum in 15 pigs and compared the results from visual inspection with histology and microdialysis. Three hours of ischemia followed by reperfusion appeared to be the upper limit for viability in this model.