RT Book, Section
A1 Gomella, Tricia Lacy
A1 Eyal, Fabien G.
A1 Bany-Mohammed, Fayez
SR Print(0)
ID 1168357002
T1 Polycythemia: On Call
T2 Gomella's Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 8e
YR 2020
FD 2020
PB McGraw-Hill Education
PP New York, NY
SN 9781259644818
LK accesspediatrics.mhmedical.com/content.aspx?aid=1168357002
RD 2024/04/24
AB The  hematocrit  (Hct)  is  68%  in  a  newborn.  Polycythemia  is  an  increase  in  total  erythrocyte  mass  empirically  defined  as  a  venous  Hct  >2  standard  deviations  above  the  normal  value  for  postnatal  and  gestational  age.  An  infant  who  has  a  peripheral  venous  Hct  >65%  or  a  hemoglobin  >22  g/dL  is  considered  polycythemic.  Polycythemia  occurs  in  1%  to  5%  of  healthy  newborns  (1%–2%  at  sea  level  and  5%  at  high  altitude)  and  is  rare  in  premature  infants  14.6  centipoise  (shear  rate  of  11.5  seconds)  and  is  also  defined  as  2  standard  deviations  greater  than  the  norm.  Viscosity  rises  linearly  until  the  Hct  reaches  60%  but  increases  exponentially  when  it  reaches  70%.