Evaluating tissue perfusion using labelled water indicator microdialysis in a rat model of haemorrhagic shock.
The indicator microdialysis technique with (3)H(2)O was evaluated as a method for assessing local blood flow in skeletal muscle and liver in a rat model of haemorrhagic shock. Microdialysis probes were inserted into the hind limb muscle and liver of 12 rats and perfused with a solution containing (3)H(2)O. Haemorrhagic shock was induced in eight rats by repeated blood withdrawals; four rats were used as a control group. The outflow to inflow (O/I) ratio of water activity, lactate and pyruvate contents in the dialysate were repeatedly measured. The ratio of lactate to pyruvate (L/P) was calculated. There was no correlation between blood loss and O/I ratio (r = 0.323 for liver, r = 0.300 for muscle), between the mean arterial pressure and O/I ratio (r = 0.460 for liver, r = -0.301 for muscle) or between the concentration of lactate and O/I ratio (r = -0.237 for liver, r = 0.454 for muscle). A significant correlation was found between blood loss and lactate concentration in muscle (r = 0.619, p < 0.0001). We suppose that microdialysis with (3)H(2)O cannot be used as a sensitive method to estimate regional blood flow changes during haemorrhagic shock in rats. Measuring lactate, pyruvate and L/P ratio in the microdialysate seems to be a superior method to assess tissue hypoperfusion caused by haemorrhagic shock in rats.
Department of Anaesthesiology, Resuscitation and Intensive Care Medicine, Charles University in Prague, University Hospital in Hradec Kralove, Hradec Kralove, Czech Republic.
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D000818:Animals; D001794:Blood Pressure; D004195:Disease Models, Animal; D019344:Lactic Acid / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D018482:Muscle, Skeletal / Q000378:metabolism*; D010477:Perfusion; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012771:Shock, Hemorrhagic / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D013997:Time Factors; D014867:Water / Q000378:metabolism*
D014867:Water; D019344:Lactic Acid; D019289:Pyruvic Acid