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document
Effects of preoperative intentional hemodilution on the extravasation rate of albumin and fluid . OBJECTIVE To evaluate the effects of preoperative intentional hemodilution with 4 % albumin solution on the extravasation rate of intravascular albumin and fluid in surgical patients . DESIGN A prospective , randomized , clinical study . SETTING University teaching hospital . PATIENTS Two groups ( control group [ group 1 ] and hemodiluted group [ group 2 ] ) of 13 healthy patients were studied during a long-term ( > 4 hrs ) surgical procedure . INTERVENTIONS Autologous technetium-99m ( 99mTc ) -labeled red blood cells and indium-oxine ( ( 111 ) In ) -labeled human serum albumin were injected intravenously during anesthesia at T = 0 min in the two groups for the determination of total blood volume and albumin diffusion space , respectively . In addition , body tetrapolar electrical impedance was used to assess extracellular fluid volume . In the hemodiluted group ( group 2 ) , 15 mL/kg of blood was withdrawn over 30 mins ( T = 20 mins to T = 50 mins ) and simultaneously replaced by an equal volume of 4 % albumin solution ( 0.6 g/kg ) . MEASUREMENTS AND MAIN RESULTS The albumin diffusion space , the colloid oncotic pressure , the plasma albumin concentration and the electrical impedance were measured before ( T = 10 mins ) and after ( T = 60 , 120 , and 240 mins ) hemodilution . Urine was collected from T = 10 mins to T = 240 mins . The total blood volume was calculated at T = 10 mins . No differences in the initial values were found between the two groups . In group 2 , hemodilution ( hematocrit 30 +/- 3 % ) resulted in a steeper increase in the albumin diffusion space ( p < .05 ) and a progressive decrease in the body electrical impedance ( p < .05 ) . The extravasation rate of albumin was 0.052 +/- 0.007 mL/kg/min in group 2 vs. 0.038 +/- 0.020 mL/kg/min in group 1 ( p < .05 ) . The value of calculated plasma volume at T = 0 min did not shown any difference between the two groups . This value was then lower than expected in group 2 , corresponding to a loss of plasma volume of > 3 mL/kg . Urine output was significantly lower in group 2 than in group 1 ( 0.7 +/- 0.4 vs. 1.4 +/- 1.0 mL/min , respectively ; p < .05 ) . A comparable decrease in colloid oncotic pressure and in plasma albumin concentration was observed in both groups . CONCLUSIONS These results suggest that preoperative hemodilution using 4 % albumin on a 1:1 volume basis for blood substitution during a prolonged surgical procedure with reduced blood losses enhances the extravasation rate of albumin and fluid to the interstitial tissues , impeding the maintenance of isovolemia . These findings support the use of a volume of infused colloid solution higher than that of withdrawn blood during preoperative hemodilution .
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Intervention_Physical
intentional hemodilution
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Intervention_Pharmacological
albumin
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Intervention_Pharmacological
Autologous technetium-99m ( 99mTc ) -labeled red blood cells
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Intervention_Pharmacological
indium-oxine ( ( 111 ) In ) -labeled human serum albumin were injected intravenously
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Outcome_Physical
extravasation rate of albumin and fluid
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Outcome_Physical
albumin diffusion space , the colloid oncotic pressure
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Outcome_Physical
plasma albumin concentration
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Outcome_Physical
electrical impedance
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Outcome_Physical
total blood volume
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Outcome_Physical
albumin diffusion space
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Outcome_Physical
body electrical impedance
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Outcome_Physical
extravasation rate of albumin
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Outcome_Physical
value of calculated plasma volume
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Outcome_Physical
loss of plasma volume
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Outcome_Physical
Urine output
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Outcome_Physical
colloid oncotic pressure and in plasma albumin concentration
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Participant_Condition
surgical
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Participant_Sample-size
13