Umbilical artery catheter blood sampling volume and velocity: impact on cerebral blood volume and oxygenation in very-low-birthweight infants.
OBJECTIVE
Blood sampling from umbilical artery catheters decreases cerebral blood volume and cerebral oxygenation. The aim of this study was to assess the impact of sampling volume and velocity.


METHODS
Forty-eight infants, median birthweight 965 g (480-1500 g), median gestational age 27 wk (23-34 wk), were studied during routine blood sampling from umbilical artery catheters. The sampling procedure was performed following a strict protocol for draw-up volume (1.6 ml), sampling volume (1.7 ml or 0.2 ml), re-injection volume (1.6 ml) and flushing volume (0.6 ml), time of aspiration (40 s or 80 s), re-injection (30 s) and flushing (6 s). In each infant, sampling volume and aspiration time were subject to sequential variation in a randomized fashion (1.7 ml/40 s, 1.7 ml/80 s, 0.2 ml/30 s). Using near-infrared spectroscopy, changes in concentrations of cerebral oxygenated and deoxygenated haemoglobin were measured, and changes in cerebral blood volume and cerebral oxygenation were calculated.


RESULTS
During all three sampling procedures, oxygenated haemoglobin decreased significantly from baseline, whereas deoxygenated haemoglobin did not change. Correspondingly, a decrease in cerebral blood volume and cerebral oxygenation occurred. This decrease was not affected significantly by extending the sampling time from 40 s to 80 s, whereas it was blunted by reducing the amount of blood withdrawn.


CONCLUSIONS
Blood sampling from umbilical artery catheters induces a decrease in cerebral blood volume and cerebral oxygenation. The magnitude of the decrease depends on the blood volume withdrawn but not on sampling velocity.
Roll
Claudia
C
Department of Paediatrics, University Hospital, Essen, Germany. Cludia.Roll@kinderklinik-datteln.de
Hüning
Britta
B
Käunicke
Matthias
M
Krug
Jens
J
Horsch
Sandra
S
D001794:Blood Pressure; D001800:Blood Specimen Collection / Q000009:adverse effects / Q000379:methods*; D002406:Catheterization, Peripheral; D002560:Cerebrovascular Circulation; D005260:Female; D006339:Heart Rate; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D008297:Male; D010092:Oximetry; D010108:Oxyhemoglobins / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D014469:Umbilical Arteries
D006454:Hemoglobins; D010108:Oxyhemoglobins