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Cerebral blood flow velocity in infants with polycythemia and hyperviscosity: effects of partial exchange transfusion
Insights
Neonates with polycythemia and hyperviscosity experience reduced cerebral blood flow velocity. Partial exchange transfusion with Plasmanate effectively normalizes cerebral blood flow and vascular resistance in these infants.
Area of Science:
- Neonatal Medicine
- Pediatric Cardiology
- Vascular Physiology
Background:
- Neonates with polycythemia and hyperviscosity often exhibit altered cerebral hemodynamics.
- Elevated hematocrit and blood viscosity can impair cerebral blood flow.
- Understanding these hemodynamic changes is crucial for neonatal care.
Purpose of the Study:
- To investigate the impact of polycythemia and hyperviscosity on cerebral blood flow velocity and vascular resistance in neonates.
- To evaluate the efficacy of partial exchange transfusion with Plasmanate in correcting these hemodynamic abnormalities.
Main Methods:
- Studied 11 neonates with polycythemia and hyperviscosity before and after partial exchange transfusion.
- Measured anterior cerebral artery blood flow velocity using a Doppler velocimeter.
- Calculated cerebral blood flow and vascular resistance from velocity tracings and Pulsatility Index.
Main Results:
- Polycythemia and hyperviscosity were associated with decreased cerebral blood flow velocity.
- Neonates showed increased cerebral vascular resistance due to high blood viscosity.
- Partial exchange transfusion significantly increased blood flow velocity and reduced vascular resistance.
- Post-transfusion values normalized and were comparable to control infants.
Conclusions:
- Infants with polycythemia and hyperviscosity have significantly impaired cerebral blood flow velocity and elevated vascular resistance.
- Partial exchange transfusion with Plasmanate is an effective treatment to normalize cerebral hemodynamics in these neonates.
- Restoring normal blood viscosity is key to improving cerebral perfusion in polycythemic neonates.
Abstract:
To determine if there are significant changes in cerebral blood flow velocity and vascular resistance in neonates with polycythemia and hyperviscosity, 11 such infants were studied before and after partial exchange transfusion with Plasmanate. Seven matched control infants were also studied. Blood flow velocity of the anterior cerebral artery was measured with a bidirectional continuous waveform Doppler velocimeter. Blood flow and vascular resistance were calculated from the velocity tracings, using the area under the velocity curve and the Pulsatility Index. Reduction in hematocrit and viscosity produced significant increases in blood flow velocity and a reduction in vascular resistance. The postexchange values were similar to those of the control group. These results indicate that infants with polycythemia and hyperviscosity have decreased cerebral blood flow velocity and increased vascular resistance which normalize after partial Plasmanate exchange transfusion.