Phototherapy for newborn jaundice.
What is phototherapy?
Phototherapy is the use of light to treat newborn jaundice. Newborn jaundice is due to the presence of higher than normal level of bilirubin in blood.
Historically, in England some nurses reported that a new, well lit nursery had significantly lesser cases of newborn jaundice when compared to the hospital's older, darker nursery. Also, some observant nurses from other parts of world reported that babies placed in cribs closer to the window had less jaundice than other babies in the ward. Such observations led to the discovery of the therapeutic effect of light in newborn jaundice.
How does phototherapy cure jaundice?
When baby is placed under a source of blue light (of wavelength 425 to 550 nm), light reacts with bilirubin in the blood flowing through the baby's skin. Bilirubin which is water insoluble is converted to substances like lumirubin which are water soluble and hence easily excreted through poo and urine. Formation of lumirubin is the most important way of excreting the excessive bilirubin. There are other less important ways by which phototherapy aids in excreting bilirubin which includes photo-oxidation and configurational isomerization.
How is phototherapy given?
Phototherapy is given in two ways:
- Phototherapy unit: with fluorescent lights (daylight white, blue, green, blue-green), tungsten halogen or quartz halide spotlights, High intensity blue gallium nitride LEDs.
- Bilirubin blanket (Bili-blanket) : Light from a high intensity lamp is delivered to a fibre optic blanket.
Tungsten halogen spot light has less spectral power. They are often used as a part of radiant warmer. High intensity Gallium Nitride diodes emit less UV and Infra red radiation and hence the amount light in blue green spectrum can be customised. They can also be brought very close to infants, unlike halogen spot lamps.Gallium nitride LEDs are considered more effective.
Bilirubin blankets are woven fibre optic pads. Halogen light beams from a source (light box) are transmitted though a cord of fibre optic filaments to a flexible pad which is placed beneath or wrapped around the baby. The blanket does not produce heat and delivers light in the 425 to 475 nm range. Generally, as the fibre optic pads cover a small surface of the baby's skin, bili blankets are considered less efficient than conventional phototherapy. They are often used in conjunction with a phototherapy unit. Bili blankets are portable, does not need use of eye pad (because light does not shine directly in to baby's eyes) ,offers chances for bonding and feeding without interrupting phototherapy and is hence preferred by parents. Bilirubin blankets are used for home phototherapy, when the level are in optional range, to prevent further increase in bilirubin level.
Contrary to the popular misconception, Ultra violet rays are not used in phototherapy. What little UV light that the light sources emit, are of longer wavelength than those causing redness, and even such small amount of emitted UV rays are absorbed by the glass wall of the tubes.
When is phototherapy given?
Babies are treated with phototherapy when it is believed that their bilirubin levels could enter toxic range. Indication for commencing phototherapy depends on each hospital's nursery guidelines.(For example, according to AAP guidelines,healthy term babies at 72 hours of life are started on phototherapy when their bilirubin level reaches 18mg/dl). Sick babies and premature babies are put on a more conservative approach.
How fast does phototherapy act?
The rate at which bilirubin is reduced depends on many factors-
- Blue green spectrum is more effective: Hence special LED or special blue tubes which has a maximum output in the blue green spectrum are used for intensive phototherapy.
- Closer the infant is to the blue fluorescent tube, faster the clearance will be. It is desirable to place the infant within 10 to 15 cms of the source. However, halogen tubes may cause burns when placed too close and so manufacturer's guidance should strictly be followed in case of halogen tubes.
- Area of the baby's body exposed: The baby is placed with only diaper and eye pads. The exposure can be intensified using double phototherapy (blue lights above and below the glass bassinet), or by lining the incubator or warmer bed with aluminium foil.
- If there is ongoing production of bilirubin (as in some blood diseases like hemolytic anaemia) it is necessary to start phototherapy at lower levels.
- The bilirubin level at diagnosis: For higher bilirubin levels, intensive phototherapy is given.
On an average, in term babies admitted for intensive phototherapy, there is a decline of 30 to 40% in the first 24 hours, the maximum decline being in the first 4 to 6 hours (as much as 0.5 to 1mg/dl per hour decline in the first 4 to 6 hours). With standard therapy there is a 6 to 20% decline in the first 24 hours.
Intermittent versus continuous phototherapy?
Studies have shown conflicting results about whether intermittent phototherapy is as effective as continuous phototherapy. As the most rapid breakdown of bilrubin takes place in the first few hours of commencing phototherapy, in most cases brief periods of interruption for holding and feeding the babies are allowed. But babies with severe jaundice need continuous, intensive phototherapy.
What is intensive phototherapy?
Intensive phototherapy is providing an irradiance in the 430 to 490 nm band (usually 30 µW/cm2per nm) to as much area of the baby's body as possible. This is given by using multiple phototherapy units or by combining phototherapy with fibre optic pads, in an uninterrupted manner. Double phototherapy is twice as effective in preterms and at least 50% more effective in term babies.
When is phototherapy stopped?
There are no specific end point for stopping phototherapy. Judgement depends on individual cases, depending on -weight of baby, if the baby is term or preterm and age of the baby. Generally in healthy term babies, phototherapy is discontinued when the bilirubin level falls to 13 to 15 mg/dl. Babies are followed up for rebound jaundice , where a repeat blood test may be necessary.
What is rebound jaundice?
Rebound jaundice is a surge in bilirubin levels soon after phototherapy is stopped. Rebound jaundice is significant in preemies, babies with positive direct coomb's test (indicating hemolysis) and in babies who have received less than 72 hours of phototherapy. In such cases, a repeat blood test 24 hours after discharge may be necessary.
When is phototherapy dangerous?
Phototherapy is usually a safe procedure.
In a rare genetic condition called, 'congenital porphyria', phototherapy is contraindicated as it causes severe blistering. In jaundice due to liver disease, phototherapy can lead to pigmentation of skin and urine called 'bronze baby syndrome' and in such cases alternative treatment like exchange transfusion is considered. Blistering can also occur in obstructive jaundice.
What are the complications of phototherapy?
Phototherapy has been in use for more than three decades and millions of babies have benefited from phototherapy. Serious side effects are rare and phototherapy is generally considered a simple, safe and cheap procedure. Minor side effects are
- Frequent loose stools- green or watery poo is common. This along with increased insensible water loss can lead to dehydration. Frequent bowel movements help in excreting bilirubin and will stop when phototherapy is discontinued. Babies are required to be fed frequently. Dehydration may have to be corrected by supplementing with formula or fluid administration. Over-heating can also occur but is uncommon with LEDs that produce less heat and with fibre-optic blankets.
- Baby's eyes are protected by soft eye patches. Although some animal models have shown to develop retinal degeneration on exposure to constant light, similar findings are not documented in humans. Nevertheless baby's eyes are covered with eye pads always.
- Babies being kept in isolation and under bright light with eyes covered- there are concerns about this temporary interruption of visual-sensory stimulation (cuddling, being talked to etc) and doubtful alteration in circadian rhythm. Isolation and parental stress can interfere with early baby-parent bonding. These effects can be overcome by allowing the parents to cuddle and bond with baby during brief feeding sessions and alleviating parental anxiety by keeping them informed and reassured. Bilirubin blankets are popular with parents as they are portable and do not interfere with mother-baby bonding and hence are prescribed when clinical situation permits.
What can I do to help my baby who is on phototherapy?
- conventional phototherapy
It is generally not necessary to interrupt breastfeeding. If baby has to be supplemented with formula or if breastfeeding has to be interrupted, seek consultation for pumping and maintaining breastfeeding. Make your feeding choices (breast or formula feeding) known to your doctors.
Use the feeding sessions to cuddle and bond with the baby with eye patches taken off (unless baby is on continuous, intensive photo therapy)
Do not apply any cream, lotion or vaseline on baby's skin.
Make sure that as much of baby's skin as possible is exposed to light. Babies are usually naked but for their eye patches and a small diaper. Change diapers whenever soiled.
Always cover the baby's eyes with pads when on phototherapy. Remember to put on the eye patches before switching on the lights,when you place the baby back in the incubator after feeding.Make sure that they are not too tight. Report if you see any redness or discharge in baby's eyes.
Explain to your visitors that your baby has to spend most of his/ her time under the phototherapy lights. They can talk and look at the baby when she is lying under the lights.
Baby's position may have to be changed to maximise exposure. Temperature is recorded frequently to keep the baby warm and avoid overheating.
If you have any questions or doubts, talk with your baby's nurse and doctor. Keep yourself informed and reassured. Stay calm, babies often seem to sense mother's anxiety.
Baby's skin appears bleached as bilirubin is broken down. It becomes impossible to assess jaundice by skin color after exposing to phototherapy
- Fibre optic pads (Bili blankets):
Swaddle the baby in the blanket, covering both baby and the fibre-optic pad. Do not wrap the blanket too tight. Baby can also be dressed in a sleeper.
It is important to ensure that the lighted area on the pad is against your baby's skin at all times during treatment. The disposable cover should be the only material between baby's skin and the light emanating surface. Change the disposable cover when soiled. Baby's clothing can be worn over the pad.
When feeding or holding your baby, ensure that the tube is not pulled off and disconnected from the phototherapy unit or light box.
The pad can remain on the baby round the clock ,during feeding and when baby is sleeping. Switch off when you take the baby off for bathing.
Place the light source on a flat stable surface. Do not keep anything on top of the light source or the cable.
Eye patches need not be used as the light does not shine in to baby's eyes.
Call your doctor/nurse if you have any doubts about the use of bili blankets.
Can sunlight be used to treat baby's jaundice?
Although sunlight provides sufficientirradiance in the 425- to 475-nm band to provide phototherapy,AAP does not recommend using sunlight because of the practical difficulties involved in safely exposing a nakednewborn to the sun either inside or outside (and avoiding sunburn)