title: Dimension and overlap of femoral and neck blood vessels in neonates.
abstract: BACKGROUND
  Neonates frequently require access to their central blood vessels. However, limited data exist relating to the size and the anatomical relation of the femoral and neck vessels for neonates of different postmenstrual ages.
  
  
  OBJECTIVE
  1) The size of central blood vessels increases with postmenstrual age of the neonate. 2). External rotation with abduction at the hip will decrease the degree of overlap between the femoral artery and vein. 3) The degree of overlap decreases with increasing postmenstrual age.
  
  
  METHODS
  Prospective descriptive cohort study.
  
  
  RESULTS
  Femoral and neck vessel sizes were assessed using ultrasound for three postmenstrual age groups: group A (26 ± 1 wks), group B (32 ± 1 wks), and group C (38 ± 1 wks). The degrees of overlap (major, >50% overlap; minor, ≤50% overlap; no overlap) between the femoral vessels were assessed at the level of the inguinal ligament and 1 cm below the inguinal ligament in a straight hip and in external rotation with abduction of the hip positions. A total of 52 nonconsecutive subjects (group A, seven; group B, 21; group C, 24) were studied. The mean blood vessel dimensions increased with increasing postmenstrual age. Correlation of blood vessel size to growth measurements was better in group A + group B compared to group C. Overlap between the femoral vein and the femoral artery across the neonatal age groups at the level of the inguinal ligament ranged from 57% to 79% and from 43% to 98% at 1 cm below the inguinal ligament. The degree of overlap did not decrease with positioning of the lower extremity in external rotation with abduction of the hip. In the neck blood vessels, the majority of observations showed either minor or major overlap of neck blood vessels in all three groups (group A, 79%; group B, 86%; group C, 90%).
  
  
  CONCLUSIONS
  Central blood vessel size increases with increasing postmenstrual age. Correlation of blood vessel size to anthropometric measurements was better in the premature neonates compared to term neonates. A high degree of overlap exists within the femoral and cervical blood vessels. In the femoral vessels, the degree of overlap did not decrease with external rotation with abduction of the hip at any postmenstrual age.
authors.affiliation: Division of Pediatric Critical Care Medicine, College of Medicine, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock, AR, USA.
authors.forename: Muayyad
authors.initials: M
authors.lastname: Tailounie
authors.forename: Lou A
authors.initials: LA
authors.lastname: Mcadams
authors.forename: Kristie C
authors.initials: KC
authors.lastname: Frost
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Gossett
authors.forename: Jerill
authors.initials: J
authors.lastname: Green
authors.forename: Adnan T
authors.initials: AT
authors.lastname: Bhutta
authors.forename: Umesh
authors.initials: U
authors.lastname: Dyamenahalli
authors.forename: Michael L
authors.initials: ML
authors.lastname: Schmitz
authors.forename: Parthak
authors.initials: P
authors.lastname: Prodhan
mesh_terms: D001827:Body Height; D001835:Body Weight; D002339:Carotid Arteries / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015331:Cohort Studies; D005260:Female; D005263:Femoral Artery / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005268:Femoral Vein / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005865:Gestational Age; D006615:Hip; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007601:Jugular Veins / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008297:Male; D056888:Patient Positioning; D011446:Prospective Studies; D012399:Rotation; D014463:Ultrasonography