Introduction: 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.
Hypothesis: 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.
Design: Prospective descriptive cohort study.
Measurements and Main 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.
From the Divisions of Pediatric Critical Care Medicine (JGr, ATB, PP), Neonatal-Perinatal Medicine (LAM, KCF), and Pediatric Cardiology (JGo, ATB, UD, PP) and Pediatric Cardiothoracic Anesthesiology (MLS), College of Medicine, University of Arkansas for Medical Sciences, Arkansas Children’s Hospital, Little Rock, AR; and Division of Pediatric Critical Care Medicine (MT), Toledo Children’s Hospital, University of Toledo, Toledo, OH.
Institution where work was performed: University of Arkansas for Medical Sciences, Arkansas Children’s Hospital, Little Rock, AR.
The authors have not disclosed any potential conflicts of interest.
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