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The effect of vascular constriction on umbilical venous pulsation
Author(s) -
Skulstad S. M.,
Kiserud T.,
Rasmussen S.
Publication year - 2004
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.971
Subject(s) - medicine , umbilical vein , umbilical cord , fetus , constriction , vein , gestational age , hemodynamics , cardiology , anesthesia , obstetrics , pregnancy , anatomy , chemistry , genetics , biology , in vitro , biochemistry
Objectives Umbilical venous pulsation is an important sign of hemodynamic compromise, but is also found under normal physiological conditions. Mathematical modeling suggests that vascular compliance is a determinant for pulsation, and we tested this by studying velocity pulsation at three sites on the umbilical vein. Methods In a cross‐sectional study of 279 low‐risk pregnancies (20–40 weeks' gestational age) blood flow velocity in the umbilical vein was determined before, within and after the umbilical ring in the fetal abdominal wall, and the incidence and magnitude of pulsation (the difference between the maximum and minimum velocity during a pulse, and pulsatility index) were noted. Based on the fact that the vessel cross‐sectional area is an important determinant of compliance, we measured the diameter and time‐averaged maximum velocity to reflect variation in diameter and compliance at the three sites. Results The incidence of umbilical venous pulsation was higher at the umbilical ring in the abdominal wall (242/279, 87%, 95% CI 82–90) than in the cord (43/198, 22%, 95%CI 16–27) or intra‐abdominally (84/277, 30%, 95% CI 25–36) ( P < 0.001). When pulsation was observed intra‐abdominally, the pulsatility was not different from that at the umbilical ring ( P = 0.16). However, the lowest pulsatility was found in the cord vein ( P < 0.0001), where the largest vein diameter was found. Conclusion The high incidence of venous pulsation at the umbilical ring where diameter and compliance are low supports the suggestion that local compliance is an important factor influencing pulsation in fetal veins. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.