Quantification of fluorescein distribution to strangulated rat ileum

Following various periods of strangulation, the fates of intestinal segments were predicted by standard clinical criteria and visual (Wood's lamp) and fluorometric (perfusion fluorometer) assessment of fluorescein distribution. With fluorometry, a means of quantifying fluorescence transmitted via a fiberoptic light guide, the delivery and removal of fluorescein were monitored and analyzed. If either was restricted significantly, tissue death was predicted. Analysis of computerized graphic patterns or simple interpretation of fluorometric readings at two time points predicted tissue fate with 98% accuracy and a 93% negative predictive value. Wood's lamp evaluation had only a 53% accuracy and a 33% negative predictive value, while standard clinical criteria had an 81% accuracy and a 53% negative predictive value. Fluorescein leakage in segments which suffered significant endothelial damage provided staining patterns that incorrectly suggested viability. By monitoring elimination as well as uptake of dye, fluorometry provided much greater discrimination than did Wood's lamp inspection in this setting. In addition, fluorometry was readily repeatable within minutes, as fluorescence remaining from a previous injection could be subtracted from new, postinjection values.