Nursing Center - Journal Issue

Abstract

Phototherapy is the use of visible light for the treatment of hyperbilirubinemia in the newborn. This relatively common therapy lowers the serum bilirubin level by transforming bilirubin into water-soluble isomers that can be eliminated without conjugation in the liver. The dose of phototherapy is a key factor in how quickly it works; dose in turn is determined by the wavelength of the light, the intensity of the light (irradiance), the distance between the light and the baby, and the body surface area exposed to the light. Commercially available phototherapy systems include those that deliver light via fluorescent bulbs, halogen quartz lamps, light-emitting diodes, and fiberoptic mattresses. Proper nursing care enhances the effectiveness of phototherapy and minimizes complications. Caregiver responsibilities include ensuring effective irradiance delivery, maximizing skin exposure, providing eye protection and eye care, careful attention to thermoregulation, maintaining adequate hydration, promoting elimination, and supporting parent-infant interaction.

Phototherapy is the use of visible light for the treatment of hyperbilirubinemia, or jaundice, in the newborn.1 It is perhaps the most common nonroutine therapy applied in the newborn population. How phototherapy came to be is a fascinating story, with a nurse at its center.2

Sister Ward, the nurse in charge of the Premature Unit at Rochford General Hospital in Essex, England, firmly believed in the restorative powers of fresh air and sunshine (Figure 1). On sunny days, she would wheel the infants outdoors into the hospital courtyard, returning them to the nursery just before the doctors-who were not as keen on this practice-arrived for ward rounds. One day in 1956, Sister Ward showed the physicians an undressed infant whose skin was pale except for a triangular area that appeared much yellower than the rest of its body. Dr R. H. Dobbs asked her if she had painted the baby's skin with iodine. She denied having done so, telling him that what she held in her arms was a jaundiced infant whose color had faded except in an area that had been covered by the corner of a sheet.2

Figure 1 - Click to enlarge in new window

FIGURE 1. Miss Jean Ward, in 1956, with one of the earliest infants given phototherapy at Rochford General Hospital. Courtesy of BMJ Publishing Group.

Subsequently, physicians and scientists at Rochford Hospital discovered that the levels of bilirubin pigment in tubes of blood left sitting in the sun also dropped dramatically. Putting these observations together, the idea of phototherapy for neonatal jaundice was born. The very first phototherapy unit incorporating an artificial light source instead of natural sunlight was devised and tested by Cremer et al 3 at Rochford Hospital, and the results were reported in The Lancet, in 1958 (Figure 2).

Figure 2 - Click to enlarge in new window

FIGURE 2. The first artificial light apparatus devised for cradle illumination of infants at Rochford General Hospital. The hemicylindrical stainless steel reflector, suspended on a height-adjustable moveable gantry, contains eight 24-in light blue 40-W fluorescent tubes spaced 2 in apart. A cot can be wheeled underneath the reflector, and the lights can be switched on separately to vary the amount of power delivered.

Phototherapy was not used in the United States until the landmark study of Lucey et al 4 was published in Pediatrics a full decade later. This randomized controlled trial demonstrating the effectiveness of phototherapy led to its acceptance as a simple, inexpensive, and relatively safe way to prevent hyperbilirubinemia in premature infants.

Normal Bilirubin Metabolism

Humans continuously form bilirubin, and newborn infants produce relatively more bilirubin than any other age group. The typical bilirubin load of the newborn is quite high, 2 to 3 times that of an adult. Bilirubin is a product of the normal destruction of circulating erythrocytes (which have a shortened lifespan in the newborn infant) and increased turnover of cytochromes.5 Some infants have excessive bilirubin production, and a correspondingly elevated load of unconjugated bilirubin (Table 1).

Table 1 - Click to enlarge in new window

TABLE 1. Mechanisms of Hyperbilirubinemia

Unconjugated bilirubin is lipid-soluble and must be transported to the liver in the plasma, bound reversibly to albumin.6 In the liver, bilirubin is transported across hepatic cell membranes, where it binds to ligandin for conjugation. A liver enzyme, uridine diphosphoglucuronate glucuronosyltransferase, conjugates bilirubin, converting it to water-soluble bilirubin pigments that can be excreted into the bile and exit the body via the intestines, or, to a lesser degree, filtered through the kidneys (Figure 3). Bilirubin pigments in the gut that are not eliminated can be reabsorbed into the circulation as unconjugated bilirubin, essentially recycling the bilirubin load, a process called enterohepatic recirculation. Thus, babies with reduced conjugation or elimination of bilirubin are also at risk for hyperbilirubinemia (Table 1). A more detailed explanation of newborn bilirubin metabolism can be found in an article in the April 2002 issue of this journal.7

Figure 3 - Click to enlarge in new window

FIGURE 3. Neonatal bilirubin metabolism. From Stokowski.

How Phototherapy Works

Phototherapy converts bilirubin that is present in the superficial capillaries and interstitial spaces of the skin and subcutaneous tissues to water-soluble isomers that are excretable without further metabolism by the liver (Figure 4). Neonatal jaundice expert Maisels suggests that phototherapy is much like a percutaneous drug.6,8 When phototherapy illuminates the skin, an infusion of discrete photons of energy are absorbed by bilirubin much like a drug molecule binds to a receptor. Bilirubin molecules in light-exposed skin undergo relatively quick photochemical reactions-configurational isomerization, structural isomerization, and photooxidation-to form nontoxic, excretable isomers. These bilirubin isomers have different shapes than the native isomer, are more polar, and can be excreted from the liver into the bile without undergoing conjugation or requiring special transport for their excretion.9 Urinary and gastrointestinal elimination remain important to the process of reducing the bilirubin load.

Figure 4 - Click to enlarge in new window

FIGURE 4. The mechanism of phototherapy. When bilirubin molecules absorb light, 2 main photochemical reactions occur: Native 4Z, 15Z-bilirubin converts to 4Z, 15E bilirubin (also known as photobilirubin) and to lumirubin. Unlike 4Z, 15Z bilirubin, photobilirubin can be excreted via the liver without conjugation, but its clearance is very slow and its conversion is reversible. In the bowel (away from the light), photobilirubin is converted back to native bilirubin. Lumirubin is not reversible. So, although much less lumirubin than photobilirubin is formed, lumirubin is cleared from the serum much more rapidly, and it is likely that lumirubin formation is primarily responsible for the decline in serum bilirubin that results from phototherapy. Small amounts of native bilirubin are also oxidized to monopyrroles and dipyrroles that can be excreted in the urine. This is a slow process and only a minor contributor to the elimination of bilirubin during phototherapy. Diagram courtesy of Mary Puchalski.

When Is Phototherapy Prescribed?

The aim of phototherapy is to curtail rising serum bilirubin and prevent its toxic accumulation in the brain, where it can cause the serious, permanent neurological complication known as kernicterus. Where the technology is readily available, phototherapy has nearly abolished the need for exchange transfusion to treat hyperbilirubinemia. Phototherapy is typically used either prophylactically or therapeutically.

* In preterm infants or those with a known hemolytic process, it is often used prophylactically, to prevent a significant rise in serum bilirubin.

* In late-preterm and full-term infants, it is administered at therapeutic doses to reduce excessive bilirubin levels and avoid development of bilirubin encephalopathy.

The photoisomerization of bilirubin begins almost instantaneously when the skin is exposed to light.8 Unlike unconjugated bilirubin, the photoproducts of these processes are not neurotoxic.8 Therefore, the most important intervention for the severely hyperbilirubinemic infant is to initiate phototherapy without delay.

The Importance of Dose

A robust relationship exists between the dose of phototherapy and the rate of decline in serum bilirubin level.8 Dose of phototherapy is determined by several key factors:

* Spectral qualities of the light source used (wavelength range and peak);

* Intensity of the light (irradiance);

* Distance between the light and the infant's skin;

* Body surface area exposed by the irradiated field or "footprint."

Spectral Qualities

The most effective light sources for degrading bilirubin emit light in a relatively narrow wavelength range (400 to 520 nanometers, or nm), with a peak of 460 +/- 10 nm.1 At these wavelengths, light penetrates the skin well and is maximally absorbed by bilirubin.8 Blue, green, and turquoise light (the blue-green spectrum) are considered the most effective, and some evidences suggest that given equal irradiance levels, the turquoise spectral range is more efficient in reducing bilirubin than blue because of greater skin penetration.9

Irradiance

Irradiance is the light intensity, or number of photons delivered per square centimeter of exposed body surface. The delivered irradiance determines the effectiveness of phototherapy; the higher the irradiance, the faster the decline in serum bilirubin level.10 Spectral irradiance, quantified as [mu]W/cm2/nm, varies with the design of the light source. It can be measured with a spectral radiometer sensitive to the effective wavelength of light. Intensive phototherapy requires a spectral irradiance of 30 [mu]W/cm2/nm, delivered over as much of the body surface as possible.

Combined phototherapy is often the treatment of choice for very preterm infants with hyperbilirubinemia, because it has been shown to achieve lower serum bilirubin levels with a shorter duration of treatment, and to significantly reduce exchange transfusions.15 One method frequently employed to provide combination phototherapy is to use an overhead unit above the infant (fluorescent bank light, gallium nitride light-emitting diode [LED], or halogen lamp) and a fiberoptic mattress underneath the infant. A commercially available system combines banks of fluorescent tubes on each side, with a transparent mattress containing fan-cooled fluorescent bulbs (Bili-Bassinet, Natus Medical Incorporated, San Carlos, California) (Figure 6).

Figure 6 - Click to enlarge in new window

FIGURE 6. The Bili-Bassinet (Natus Medical Incorporated) is a phototherapy delivery system that provides combination phototherapy. Courtesy of Olympic Medical.

Light-Emitting Diodes

The gallium nitride LED is one of the most recent innovations in phototherapy (Figure 7). These devices provide high irradiance in the blue to blue-green spectrum without excessive heat generation.6 Light-emitting-diode units are efficient, long-lasting, and cost-effective.1 The latest models incorporate amber LEDs to counteract the "blue hue" effect that can irritate caregivers.1

Figure 7 - Click to enlarge in new window

FIGURE 7. Phototherapy system that comprises a light-emitting diode and the option to switch between single or double phototherapy at the touch of a button (NeoBlue, Natus Medical Inc, San Carlos, California). Courtesy of Natus Medical Inc.

Halogen Spot Lights

Halogen lamp sources deliver phototherapy using 1 or more quartz halogen bulbs (Figure 8). It is possible to achieve sufficient irradiance with halogen light sources; however, devices designed with a single lamp produce a circle of light with high irradiance only in the center. Halogen systems are compact and caregiver-friendly; however, quartz halogen bulbs carry the disadvantage of generating significant amounts of heat. Manufacturer's recommendations for safe maximal distance should be followed.11 A newer device that incorporates a metal halide bulb (Giraffe SPOT PT Lite, GE Healthcare, Waukesha, Wisconsin) is an improvement over earlier halogen spotlights. The light source is located in a light box, away from the infant, resulting in a cooler light surrounding the infant. This high-intensity light is transmitted through a light pipe in a flexible gooseneck that can be adjusted for maximum light footprint.

Figure 8 - Click to enlarge in new window

FIGURE 8. Halogen spot light phototherapy system. Courtesy of GE Healthcare. Reprinted with permission.

Fluorescent Tubes

Often referred to as "bank lights," fluorescent tube phototherapy devices have been around the longest (Figure 9). It is vital to realize, however, that not all fluorescent tubes are the same. Dramatic differences exist in the irradiance produced by different types of fluorescent tubes, even within the same 425- to 475-nm wavelength.11 Bulbs used in this type of phototherapy unit include daylight, cool-white, blue, "special blue" (the most effective), or a combination of these. One system contains 6 blue tubes and 2 white tubes with an optional on/off switch. Caregivers are often bothered by the blue-hue effect produced by all blue tubes, and the blue light can impair assessment of infant skin color. The white light tubes in this unit can be switched on to minimize the blue-hue effect without hindering the effectiveness of the phototherapy treatment.

Figure 9 - Click to enlarge in new window

FIGURE 9. Phototherapy systems that incorporate fluorescent tubes. Conventional bank lights (A) can be positioned over an infant in a bassinet or incubator. Courtesy of Olympic Medical. An overhead system that combines blue and white tubes is both effective and caregiver friendly (B). Courtesy of Draeger Medical. With the BiliBed (C), the infant lays on a soft mattress of fluorescent tubes, receiving high-intensity phototherapy from below. Courtesy of Medela, Inc.

Fluorescent tube units are often positioned too far away from the infant to be effective. They should be positioned as close to the infant as possible.8 Maisels recommends that these units be placed 10 cm above nude full-term infants in bassinets for effective phototherapy. This method achieves an irradiance of 50 [mu]W/cm2 while maintaining normal body temperature8 and has been successfully implemented in jaundiced infants 37 or more weeks' gestation.16

Fiberoptic Blankets

Fiberoptic devices contain a tungsten-halogen bulb that delivers light via a cable into a plastic pad containing fiberoptic fibers (Figure 10). The pad remains cool and can be placed directly under an infant to increase the skin surface area that is exposed. The pad can also be wrapped around the infant's midsection to provide phototherapy while the infant is being held. Because the spectral power of the pad alone is low, it is commonly used in conjunction with overhead lights to provide double phototherapy.

Figure 10 - Click to enlarge in new window

FIGURE 10. Fiberoptic blanket phototherapy system. Courtesy of GE Healthcare.

Nursing Care of the Infant Receiving Phototherapy

Phototherapy is much more than just switching on a light. The efficiency with which phototherapy achieves a decline in serum bilirubin level is in large part determined by nursing care. Appropriate nursing care also minimizes the potential side effects and complications of phototherapy.

Ensure Effective Irradiance

Position phototherapy lamps or mattresses to provide the most complete skin exposure possible. Light sources should be as close to the infant as possible, with the exception of halogen-lamp phototherapy units. Overhead units that incorporate rubberized feet to rest on the incubator surface should be lowered until they are in contact with the top of the incubator.

Periodic checks of spectral irradiance produced by different phototherapy units should be conducted to ensure adequate irradiance delivery.11 Irradiance is measured with a radiometer, an instrument that gauges light in the effective wavelength for phototherapy (Figure 11). Measurements do vary among different radiometers; use the instrument recommended by the manufacturer of the corresponding phototherapy system.

Figure 11 - Click to enlarge in new window

FIGURE 11. Using a radiometer to measure irradiance level during phototherapy.

Measured irradiance can vary widely depending on where the measurement is taken.11 Irradiance in the center of the illuminated area can be double that of the periphery.11 It is preferable to take several measurements in the illuminated area at infant skin level and average them for a determination of overall effective irradiance.8

It is fairly common to see terms such as "single," "double," and "triple" used in orders prescribing phototherapy. Such terms refer only to how many pieces of equipment should be used to deliver phototherapy, and not to a specific target dose, or irradiance level. In other words, "single phototherapy" is 1 phototherapy unit, "double" is 2 units, and so forth. Naturally, it is hoped that 2 phototherapy units will deliver more efficient phototherapy than a single unit, probably through improved skin coverage. However, no standard definitions of "single," "double," and "triple" phototherapy describe phototherapy dosages in terms of target irradiance levels.

Provide Eye Protection

Opaque eye shields must be used during phototherapy to protect the infant's eyes from retinal damage (Figure 12). To adequately block the transmission of light, carefully apply eye coverings by first closing the infant's eyes and then applying shields securely. Avoid eye patches that are too tight, as they may apply undue pressure to the infant's delicate eye. Turn off the phototherapy unit and remove eye patches periodically to assess eyes for drainage, edema, and evidence of infection, to provide visual stimulation, and to encourage parent-infant interaction as appropriate on the basis of the infant's clinical status.

Figure 12 - Click to enlarge in new window

FIGURE 12. Properly positioned phototherapy eye shields.

Complications of using eye patches include apnea (from displaced eye patches obstructing the nares), eye irritation, corneal abrasion, blocked tears ducts, and conjunctivitis.17 Proper eye care is essential. Gently clean the infant's eyes with sterile cotton or soft gauze moistened with sterile water or saline, starting with the inner canthus of the eye and moving outward in a single, smooth stroke. A separate cleansing pad should be used for each eye. Gloves should be worn when providing eye care. A clean internal layer should be inserted or patches should be changed at regular intervals.

Assess Skin Exposure

The largest surface area of the infant's body, the trunk, should be positioned in the center of the light, where irradiance is highest. In most cases, it is not necessary to remove diapers or boundary materials used for postural support while providing phototherapy. Removing diapers and nesting materials around jaundiced, low-risk preterm infants weighing more than 1500 g at birth does not shorten the length of treatment.18 It is not known, however, whether diapers and/or boundary materials affect the bilirubin decline in smaller, less mature infants or in larger, more mature infants with severe hyperbilirubinemia.

The American Academy of Pediatrics recommends removing diapers for intensive phototherapy, when the serum bilirubin is approaching exchange transfusion level.11 Light-permeable diapers are also commercially available (BiliBottoms, CAS Medical Systems, Inc, Branford, Connecticut).

Proper Positioning

Frequent turning to expose different areas of skin has not been shown to improve the effectiveness of conventional (single) phototherapy.19-21

One study actually reported that the serum bilirubin levels of infants maintained in a supine position without turning declined significantly faster than those of infants who were turned prone/supine every 2 to 3 hours.20

Assess and Adjust Thermoregulation Devices

Some phototherapy units can cause a significant increase in the infant's body temperature.22 When phototherapy is directed over an incubator, immediate and sustained fluctuations can occur in the thermal environment.23 Thermal instability can occur when using either the skin- or air-control mode of the incubator. With inadequate monitoring, vigilance, and adjustments to the thermal environment, the infant can easily develop hypothermia or hyperthermia during phototherapy.

When phototherapy is initiated during air control mode, a rapid rise in body temperature usually necessitates a downward adjustment in the air temperature set point. When phototherapy is discontinued, the air temperature set point may require an upward readjustment to compensate for the loss of heat from the phototherapy lights.

During skin control mode, the air temperature usually drops when phototherapy is initiated because the additional heat warms the infant, and less environmental heat support is required. Using skin control mode is generally preferred during phototherapy because this automatic compensatory mechanism keeps the infant's body temperature within normal limits as long as the lights remain on. However, if the lights are turned off abruptly, the infant's temperature can also drop precipitously. It will then take some time for the air temperature to rise again and rewarm the infant.

Promoting Elimination and Skin Integrity

The photoproducts of bilirubin require elimination from the body in the stool or urine. Some of the photochemical reactions induced by phototherapy are reversible, meaning that the isomers can be converted back to unconjugated bilirubin if they are not eliminated in the stool.6 Enteral feeding is essential to promote stooling in hyperbilirubinemic infants. Lumirubin, an irreversible product of structural isomerization of bilirubin, is excreted in the urine as well as in the bile, so an adequate urine output is also important. An ongoing assessment of the infant's urine output is an important measure not only of hydration but also of elimination of bilirubin. The infant's urine may appear dark in color as bilirubin elimination increases.

Watery stools and diarrhea have been observed in infants undergoing phototherapy. These characteristic dark greenish stools are related to the increased excretion of unconjugated bilirubin from the intestines.6 Protective skin care is necessary to prevent perianal skin breakdown from watery stools.

Hydration

Several studies have documented an increase in transepidermal water loss during phototherapy.24,25 Excessive fluid losses via the skin are of particular concern in the smallest, most immature infants during the first week of life. These losses can be exacerbated by phototherapy, although insensible water losses are not as high with fiberoptic or LED phototherapy devices.5 Increasing fluid intake has been shown to shorten the duration of phototherapy in full-term neonates.26 Some infants may experience intestinal fluid losses from a high volume of loose stools during phototherapy. Although it is important to maintain adequate hydration, routine supplementation with intravenous fluids is not recommended.6 For breastfed infants with evidence of dehydration, supplementation with a milk-based formula inhibits the enterohepatic circulation of bilirubin and may improve the efficacy of phototherapy.6

Maintaining fluid balance by increasing incubator humidity might also be counterproductive, especially if high levels of humidity are used. A recent study 27 found that when humidification was set at more than 90%, irradiance delivery from an LED phototherapy unit was reduced by 15% and that from a halogen phototherapy unit by 45%. The mist and water condensation within the incubator are postulated to interfere with irradiance delivery.

Promoting Parent-Infant Interactions

Phototherapy necessarily separates the neonate from its mother and may interfere with the process of establishing lactation. Unless jaundice is severe, phototherapy can be safely be interrupted at feeding time to allow continuation of breastfeeding, parental visits, and skin-to-skin care.6 Remove the eye patches during these visits. If the serum bilirubin level is approaching the exchange transfusion threshold, and/or if the infant has escalating pathologic jaundice, phototherapy should be continuously maintained.6

Monitoring Bilirubin Levels

The most significant decline in bilirubin level occurs in the first 4 to 6 hours after initiating phototherapy. Conventional (single) phototherapy can decrease the serum bilirubin by up to 22% in the first 24 hours of treatment. Double phototherapy can produce a fall of as much as 29% in the first 24 hours,28 and intensive phototherapy can lower the bilirubin level by as much as 5 mg/dL/h (85 [mu]mol/L/h) In infants with rapidly rising bilirubin levels, stabilizing the bilirubin level or slowing its rate of rise should be considered valid measures of the success of therapy.29

Phototherapy lamps must be turned off while drawing blood samples for serum bilirubin testing, because the lights will act on the bilirubin pigments in the blood sample, causing the bilirubin level to decline, thereby providing erroneous data to the care team.3 Transcutaneous bilirubinometry can also be used for the evaluation of bilirubin levels in infants receiving phototherapy by using the unexposed skin of the forehead, under the infant's eye patches, for these measurements.30

After discontinuing phototherapy the bilirubin level often rises slightly, a phenomenon known as "rebound." Rebound hyperbilirubinemia is usually an elevation of no more than 1 to 2 mg/dL 31,32; however, postphototherapy rebound to clinically significant levels can occur.33 Infants at greatest risk of significant postphototherapy rebound in serum bilirubin levels requiring closer follow-up include the following:

* Premature infants;

* Infants with ongoing hemolysis (ie, positive direct Coombs tests);

* Infants treated before 72 hours of age.33

A serum bilirubin measurement obtained 24 hours after discontinuation of phototherapy will detect rebound hyperbilirubinemia.32

Indications for Intensive Phototherapy

When an infant's serum bilirubin is rising rapidly or approaching exchange transfusion level, intensive phototherapy must be instituted at maximal spectral power. This entails delivering high levels of irradiance (usually 30 [mu]W/cm 2/nm or higher) to as much of the infant's surface area as possible.1 The most efficient phototherapy units available should be used, and they should be positioned for maximum skin coverage. In these situations, additional surface-area exposure can be achieved by removing the infant's diaper and lining the sides of the bassinet, incubator, or radiant warmer with light-reflecting material such aluminum foil or white linens.34 Intensive phototherapy can produce a decline in serum bilirubin of as much as 10 mg/dL within a few hours in severely hyperbilirubinemic infants.35

Intensive phototherapy may have another, even more important benefit in an infant with a bilirubin level high enough to increase the risk for neurological damage.36 Almost as soon as the lights are switched on, the process of isomerization of bilitubin begins, converting bilirubin molecules into more polar photoisomers, that are unable to cross the blood-brain barrier independently to gain access to the neurons.35 Well before a measurable decline in serum bilirubin occurs, the effects of phototherapy are believed to protect the brain from the neurotoxic effects of bilirubin, although no studies have yet proved this hypothesis.

Limitations of Home Phototherapy and Sunlight

The irradiance and surface area exposure produced by home phototherapy units are lower than those produced by typical hospital units 11 making them less efficient at lowering the serum bilirubin level. Whether a valid indication for home phototherapy exists is questionable; current guidelines state that a bilirubin high enough to warrant treatment should be managed in the hospital.11 In the past, parents have sometimes been told to expose their jaundiced infants to sunlight. Notwithstanding phototherapy's beginnings in the sunny courtyard of an English hospital, this practice is not considered a safe or reliable way to treat jaundice.11 There are reports in the literature of infants developing kernicterus after their parents were instructed to treat their infants' jaundice at home by exposing them to sunlight, in some cases for as little as 15 minutes per day.37 Not only was this very likely to be ineffective but also it probably contributed to delays in recognition of the severity of the hyperbilirubinemia as well as delays in proper treatment.

Adverse Effects of Phototherapy

The most noticeable clinical complication of phototherapy is "bronze baby syndrome," a grayish-brown discoloration of the skin that occurs exclusively in infants with cholestatic jaundice.11 Bronze baby syndrome is believed to occur when the brown photoproducts of porphyrins, especially copper porphyrins, accumulate in the skin and their excretion is impaired by cholestasis.5 Phototherapy can damage red-blood-cell membranes, increasing their susceptibility to lipid peroxidation and hemolysis.1 These effects may contribute to the pathogenesis of disorders common in the very low-birth-weight infant, including bronchopulmonary dysplasia, retinopathy of prematurity, and necrotizing enterocolitis.1 Phototherapy has been associated with patency of the ductus arteriosus38 and ileus in very low-birth-weight infants,39 as well as retinopahty of prematurity.40 Recent evidence also suggests that phototherapy impairs immune system function through alterations of cytokine production.41 Phototherapy has been linked to the development of abnormal melanocytic nevi when the children become older. The evidence for this association is not definitive and has been debated, but at this time, this possible effect cannot be ruled out.42 Although it is not always possible to separate the effects of phototherapy from the effects of hyperbilirubinemia itself, recent research has implicated phototherapy as a risk factor for childhood asthma.43 Other rare side effects include purpura and bulbous eruptions, which can occur in infants with elevated direct bilirubin. Phototherapy is contraindicated in infants with congenital erythropoietic porphyria, because blistering and photosensitivity can result.5

Conclusion

For more than 40 years, phototherapy has been the standard of care for the treatment of hyperbilirubinemia in the newborn. In retrospect, phototherapy may have prevented nearly as much morbidity and mortality in neonatal care as the use of oxygen and has certainly done so with fewer complications. Because we have become so comfortable with this simple therapy, however, we must guard against becoming complacent about the disorder that we are treating. Hyperbilirubinemia in term and preterm infants can, in rare instances, lead to serious complications. It is essential that neonatal caregivers utilize phototherapy to its fullest potential when treating the common but not always benign problem of neonatal hyperbilirubinemia.