Long lines and central lines
In some babies who require surgery, normal feeding by mouth cannot be started for some days or weeks because the baby’s intestine is not yet working. During this time we can provide all the nutrition the baby requires by fluid that can be given into a vein. This fluid is called Total Parenteral Nutrition (TPN).
Although this can be given for short periods via a standard drip (a 2-3cm plastic needle inserted into a vein usually in the baby’s arm or leg)
the fluid may be irritant and as a result the vein is usually damaged within 1 – 2 days and the drip needs to be re-sited
resiting drips is distressing for the baby
the skin can be damaged by the irritant TPN fluid
For this reason we will often advise inserting a long line or central line in baby’s who we know are going to be slow to start milk feeds.
What is a long line?
A long line is a fine plastic tube 10 – 15 cm long that is threaded into one of the baby’s small veins in the arm or leg until it reaches a point where the veins are much larger, usually just outside the heart.
The TPN can be given through this line and because it emerges into a larger vein the risk of damage to the vein is much reduced. A long line can stay in place for several weeks, if necessary, which reduces the number of times your baby needs to have a drip inserted.
The terms 'long line' and 'central line' are often used interchangeably. We often may refer to percutaneous long lines (a very fine tube is threaded up a small vein in the arm or leg until it is in a large vein near the heart), or surgical central lines (a larger tube inserted directly into one of the larger veins in the baby’s neck during a small operation).
How is a long line inserted?
Percutaneous lines are inserted without an anaesthetic as the technique is very similar to inserting a standard drip. It can be technically difficult and may take up to an hour to do.
Surgical central lines are inserted under anaesthetic. A cut about 1cm long is made in the baby’s neck and one of the big veins located. A tiny hole is made in the vein and the central line inserted. The line is tunnelled under the skin to emerge on the baby’s chest.
Attached to the line is a cuff of material that becomes attached to the baby’s tissues just under the skin within about 7 – 10 days. This cuff and helps hold the line in place, reducing the risk of it being pulled out accidentally.
How do you decide which type of line to use?
Usually a percutaneous line is tried first. If it is not possible to insert a percutaneous line, a surgical line is inserted.
What are the possible complications of long and central lines?
Most babies do not have any complications but problems can occur and rarely these can be serious, these include:
Infection - The baby becomes unwell, has a temperature and may be quieter than usual. If infection is suspected, blood tests will be done and antibiotic treatment started. If the baby does not improve it may be necessary to remove the line.
Accidental removal -This is more likely to happen to percutaneous lines, which are only held in place by dressings and adhesive tapes. In surgical lines, once the cuff has become stuck in place (at 10 days) accidental removal is uncommon.
Blockage - Lines may become blocked with a blood clot. Sometimes the line can be unblocked but usually it will need to be removed and a new line inserted.
Vein damage - Damage to veins can occur from TPN. This may result in thrombosis (clotting) within the vein. If large veins become blocked in this way it may become increasingly difficult to find new veins into which to insert long lines. Veins that can bypass the blockage and are not normally visible may enlarge and become prominent on the baby’s skin.
Damage to the heart - This is fortunately a very rare complication. The line may damage the wall of the heart and TPN fluid may leak around the heart. This can prevent the heart from working normally. To try to avoid this complication all lines are checked by x-ray after insertion prior to use for TPN.
What happens when the long line is no longer needed?
When there are signs that your baby’s intestine is starting to work we will introduce milk feeds slowly. Once we are sure that TPN is no longer needed the long line will be removed.
Percutaneous lines can easily be pulled out without discomfort to your baby.
Surgical central lines need the cuff to be freed from the tissues under the skin. This is usually done under local anaesthetic although occasionally a general anaesthetic is required.
University Hospital Southampton NHS Foundation Trust produce guidelines as an aid to good clinical practice. They represent recognised methods and techniques of clinical practice, based on published evidence. The ultimate judgement regarding a particular clinical procedure or treatment must be made by the clinician in the light of the clinical data presented by the patient and the diagnostic or treatment options available. The guidelines issued are not intended to be prescriptive directions defining a single course of management and departure from the local guidelines should be fully documented in the patient's case notes at the time the relevant decision is taken.