Experimental model to estimate intestinal viability using charge-coupled device microscopy

Abstract

Background: Intraoperative assessment of intestinal viability following release of strangulation remains difficult. The aim of this study was to establish clinical standards for the evaluation of intestinal viability by charge-coupled device (CCD) microscopy. Methods: A rat ileus model with strangulation for between 15 and 120 rain was used. The images obtained by CCD microscopy were used to calculate maximum velocity (Vmax) ratio (ratio of Vmax of blood cell transition in the experimental segment to that in the reference segment) and S ratio (the ratio of S - the effective area of the vascular bed against the total area of the vascular bed - in the experimental segment to that in the reference segment). Rats were divided into group 1, comprising animals that survived for 7 days or more, and group 2, which consisted of animals that died within 4 days. Results: Vmax ratio and S ratio in group 1 were both significandy higher than those in group 2 (P < 0.001). No death occurred at a Vmax ratio of 0.76 or higher and an S ratio of 0.61 or more, while there were no survivors with a Vmax ratio of 0.54 or less and an S ratio of 0.51 or less. Conclusion: Vmax ratio and S ratio could be used as indices for evaluation of intestinal viability.