Fluorophotometric evaluation of capillary permeability in gram-negative shock

We developed a new method by which capillary permeability changes secondary to gram-negative sepsis can be easily monitored. In a preliminary trial, ten dogs were injected intravenously with live Escherichia coli. Progressive extravasation of fluorescein from the retinal capillary bed was demonstrated by retinal angiography, thus indicating "capillary leak." In a subsequent trial, fluorophotometry facilitated direct quantitation of this leak. Three control and three septic dogs underwent continuous hemodynamic and physiologic monitoring. Hourly retinal fluorophotometric measurements were recorded. The control group demonstrated no capillary leak nor any change in hemodynamic and physiologic status. In the septic group, there was a dramatic increase in extravascular fluorescein concentration two to four hours after E coli infusion, correlating well with hemodynamic and physiologic parameters typical of gram-negative shock.