ISOVOLEMIC HEMODILUTION WITH DEXTRAN PREVENTS CONTRAST-MEDIUM INDUCEDIMPAIRMENT OF PANCREATIC MICROCIRCULATION IN NECROTIZING PANCREATITISOF THE RAT

BACKGROUND: Previous studies demonstrated that intravenous contrast me dium (CM), as used in contrast enhanced computed tomography, aggravate s the impairment of pancreatic microcirculation (PM) characteristic of severe pancreatitis slid increases necrosis and mortality in necrotiz ing pancreatitis (NP) in rats. This study evaluates the us of isovolem ic hemodilution, which call enhance the microcirculation in sever panc reatitis, for preventing CM-induced injury. METHODS: NP was induced in 30 dextran-tolerant Wister rats by intraductal glycodeoxycholic acid and intravenous cerulein for 6 hours. PM was quantified by intravital microscopy using fluorescein isothiocyanate labeled erythrocytes. Base d On previous results, areas with low blood flow (<1.6 nL/min/cap) wer e identified and baseline recordings of capillary blood flow taken, A reduction of hematocrit to 75% of baseline was achieved by replacement of 5 mL/kg of blood with 25 mL/kg Ringer's lactate (RL) or by exchang e of 8 mL/kg of blood for the same amount of dextran 70 6%. Thereafter , the nonionic CM iopamidol (Solutrast, Byk Gulden, Konstanz, Germany) was injected during 1 minute and PM measurements repeated after 30 an d 60 minutes. RESULTS: Despite hemodilution with RL, pancreatic capill ary perfusion was significantly decreased to 87% of baseline (0.83 +/- 0.04 nL/min/cap; n = 216) 60 minutes after CM infusion (P <0.05). In contrast, capillary blood flow was significantly increased to 161% (1. 56 +/- 0.05 nL/min/cap; n = 278) in the group, treated with dextran. M oreover, the percentage of capillaries developing complete stasis was significantly lower in the dextran group (2.3 +/- 1.2%) compared to an imals diluted with RL (22.3 +/- 4.8%) (p <0.002). CONCLUSIONS: Isovole mic hemodilution with dextran prevents the additional impairment of pa ncreatic microcirculation induced by CM in NP.