Effects of intralipid infusion on blood viscosity and other haemorheological parameters in neonates and children.

AIM: To study acute haemorheological effects of intralipid in preterm and full-term neonates and children. Circulatory complications of intralipid infusion, such as increases in pulmonary and peripheral flow resistance, have been associated with impaired blood rheology.

METHODS

During total parenteral nutrition, 10 preterm infants, 10 full-term neonates and 10 children received an initial dose of intralipid as continuous infusion (0.6 g/kg) over 4 h. Additionally, blood of 10 healthy preterm infants, 10 full-term neonates and 10 adults was incubated with intralipid. Whole blood and plasma viscosity (capillary viscometer), red blood cell (RBC) deformability (rheoscope) and RBC aggregation (Myrenne aggregometer) were measured before and after intralipid infusion and before and after in vitro incubation of blood with intralipid.

RESULTS

During intralipid infusion, plasma triglyceride levels increased from 0.13 +/- 0.27 to 2.16 +/- 0.68 g/l in the preterm infants, from 0.14 +/- 0.21 to 1.64 +/- 0.54 g/l in the full-term neonates and from 0.65 +/- 0.31 to 2.26 +/- 0.60 g/l in the children. Whole blood viscosity decreased by about 10% after intralipid in all three groups due to similar decreases in haematocrit. RBC aggregation decreased by about 20% after intralipid infusion. Plasma proteins, plasma viscosity and RBC deformation were not affected by intralipid. In vitro incubation of blood with intralipid resulted in a marked reduction of RBC aggregation that was related to the intralipid concentration. At intralipid concentrations of 4 and 8 mg/ml, no RBC aggregation was noted in preterm and full-term neonates. In adults, RBC aggregation decreased by 50%.

CONCLUSIONS

Previously described deleterious effects of intralipid on circulation can not be explained by changes in haemorheological properties.