title: Residual blood volume in the umbilical cord of extremely premature infants.
abstract: BACKGROUND
  The aim of this study was to investigate residual blood volume in the umbilical cord of extremely premature infants.
  
  
  METHODS
  Twenty extremely premature infants were held at or below the placenta while the umbilical cord was clamped and cut at approximately 2-3 cm from the umbilicus within 30 s after birth. The umbilical cord was then clamped near the placenta to obtain a length of approximately 30 cm and cut. The residual blood volume in the segment of cord was drained and measured in milliliters.
  
  
  RESULTS
  Mean birthweight was 846 ± 172 g (range, 587-1180 g). The average length of the clamped segment of umbilical cord was 29.8 ± 1.5 cm (range, 27-32 cm). Total residual blood volume and residual blood volume per cm were 15.5 ± 6.7 mL (range, 6-25 mL) and 0.5 ± 0.2 mL/cm (range, 0.2-0.8 mL/cm), respectively. The residual cord blood volume per kilogram of infant weight per 30 cm was 17.7 ± 5.5 mL/kg/30 cm (range, 8.9-29.0 mL/kg/30 cm).
  
  
  CONCLUSIONS
  Infants could receive approximately 18 mL/kg of whole blood by one-time milking of 30 cm umbilical cord. With an average hematocrit of 40%, this volume is equivalent to approximately 13 mL of packed red blood cells (hematocrit 55%).
authors.affiliation: Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Hosono
authors.forename: Kotaro
authors.initials: K
authors.lastname: Hine
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Nagano
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Kayo
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Tomoo
authors.initials: T
authors.lastname: Okada
authors.forename: Hideo
authors.initials: H
authors.lastname: Mugishima
authors.forename: Shigeru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Shori
authors.initials: S
authors.lastname: Takahashi
mesh_terms: D001810:Blood Volume / Q000502:physiology*; D005312:Fetal Blood / Q000502:physiology*; D005865:Gestational Age; D006400:Hematocrit; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D014470:Umbilical Cord / Q000098:blood supply*
keywords: delayed cord clamping; delivery room resuscitation; neonate; placental transfusion; umbilical cord milking