Detection of capillary protein leakage by glucose and indocyanine green dilutions during the early post-burn period

Overestimation of the plasma volume determined by the indocyanine green (ICG) dilution method (PV-ICG) may occur after burns, since this dye has the potential of extravasation in the presence of the capillary protein leakage. Assuming that the initial distribution volume of glucose (IDVG) consistently indicates the extracellular fluid volume of highly perfused organs including plasma, overestimation of the PV-ICG can be detected by a higher PV-ICG/IDVG ratio. The present study was designed to test whether a higher PV-ICG/IDVG ratio is observed within 24 h post-burn compared to the subsequent days. Ten severely burned adult patients admitted to the ICU were studied through the 2nd post-burn day. The daily IDVG and PV-ICG were calculated using a one compartment model by simultaneous administration of glucose, 5 g, and ICG, 25 mg. Although the IDVG increased on the 1st post-burn day (p< 0.05), the PV-ICG remained unchanged. The PV-ICG/IDVG ratio within 24 h post-burn was significantly higher than that on the 1st post-burn day (p< 0.01). Results indicate that overestimation of the PV-ICG can occur within 24 h post-burn and suggest that simultaneous measurement of the IDVG and the PV-ICG would help predict the generalized capillary protein leakage after burns.