Incidence of migration and thrombus formation of umbilical venous catheters in infants

Umbilical catheters are frequently required for the management of critically
ill infants. Umbilical venous catheters (UVCs) are used for intravenous
administration of parenteral nutrition, hypertonic solutions, blood products
and medication.

Formation of thrombi is described as a possible complication in infants with
umbilical venous catheters. The indication for treatment of these thrombi is
controversial and different departments use different criteria. It is also
possible that this thrombus formation, especially in the ductus venosus, is a
physiological process and not pathologic. The ductus venosus is a fetal
structure that after birth closes permanent with thrombosis and final fibrotic
transformation of the vascular shunt into the ligamentum venosum.

Risk of formation of thrombi is increased in case of malposition of UVCs.
Malposition of UVCs may also lead to other complications, such as hepatic
necrosis, pericardial effusion and cardiac arrhythmias. The ideal location for
umbilical-vein catheter-tips is at the junction between the inferior vena cava
and the right atrium (IVC/RA-junction). The position of umbilical catheters is
checked by chest X-ray or ultrasound after umbilical catheterization and
catheters are repositioned if necessary.

We clinically observed that UVCs after placement often migrate in the following
days, despite fixation of the catheter with sutures in the umbilical cord and
tapes to the abdominal wall. Although there is abundant amount of literature
investigating the placement and location of the UVC, little is known about the
migration after placement, how often this occurs, what are the risk factors,
how much it migrates and whether the location of the tip is still acceptable.
Migration may possibly lead to more complications.

Primary objective: to determine the incidence and location of thrombi in the
umbilical venous catheter route during and after umbilical catheterization and
in the same route in infants without umbilical catheters.

Secondary objectives:
A. to investigate the frequency of migration of umbilical venous catheters in
infants.
B. to identify risk factors for migration of umbilical venous catheters.

Prospective observational case-control study

The indication for chest X-ray will be set by the attending physician. Included
infants are not exposed to extra radiation due to the study.
Cases will receive ultrasounds on day 1, 3, 7 and 14 after umbilical
catheterization, the day of removing the catheter and whenever a chest X-ray is
made on another day. Controls will receive ultrasounds on day 1, 7 and 14 after
birth.
Ultrasound examination to identify the catheter and possible thrombus will take
approximately 5 minutes. We do not expect infants to be harmed by this study,
because ultrasonography is known to be safe, non-cumbersome and will be
combined with other manipulations or examinations when possible. All premature
infants on our department receive standard cerebral ultrasounds on day 1, 3 and
7 after birth and we will combine the ultrasounds for the study as much as
possible with these cerebral ultrasounds.
Parents of participating infants may suffer from the incidental finding of
asymptomatic thrombosis. In the counselling we will inform them about the
possibility of these findings and the fact that thrombosis may be part of a
physiological process and does not always need treatment. It is possible that
infants will benefit from participation in the study because the results of the
ultrasound (more and more seen as the golden standard for verifying the
position of umbilical-vein catheters) can be used above the results of the
chest X-ray by the physician to make decisions about malposition of catheters.
This study has to be conducted in this study population because this is the
only population in which umbilical catheters are and can be used.