Fundamentals of Phototherapy for Neonatal Jaundice Laura A

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Originally published in the December 2006 issue of Advances in Neonatal Care. This version has been revised and updated August 2011 by the author.

Fundamentals of Phototherapy for Neonatal Jaundice Laura A. Stokowski, MS, RN

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. KEY WORDS: bilirubin, hyperbilirubinemia, jaundice, neonatal intensive care, newborn, phototherapy, premature infant

hototherapy is the use of visible light for the Dr R. H. Dobbs asked her if she had painted the treatment of hyperbilirubinemia, or jaundice, baby’s skin with iodine. She denied having done so, Pin the newborn.1 It is perhaps the most com- telling him that what she held in her arms was a jaun- mon nonroutine therapy applied in the newborn diced infant whose color had faded except in an area population. How phototherapy came to be is a fasci- that had been covered by the corner of a sheet.2 nating story, with a nurse at its center.2 Subsequently, physicians and scientists at Rochford Sister Ward, the nurse in charge of the Premature Hospital discovered that the levels of bilirubin pig- Unit at Rochford General Hospital in Essex, England, ment in tubes of blood left sitting in the sun also firmly believed in the restorative powers of fresh air dropped dramatically. Putting these observations and sunshine (Figure 1). On sunny days, she would together, the idea of phototherapy for neonatal jaun- wheel the infants outdoors into the hospital court- dice was born. The very first phototherapy unit incor- yard, returning them to the nursery just before the porating an artificial light source instead of natural doctors—who were not as keen on this practice— sunlight was devised and tested by Cremer et al3 at arrived for ward rounds. One day in 1956, Sister Rochford Hospital, and the results were reported in Ward showed the physicians an undressed infant The Lancet, in 1958 (Figure 2). whose skin was pale except for a triangular area that Phototherapy was not used in the United States appeared much yellower than the rest of its body. until the landmark study of Lucey et al4 was published in Pediatrics a full decade later. This randomized controlled trial demonstrating the effectiveness Author Affiliations: Inova Fairfax Hospital for Children, Falls of phototherapy led to its acceptance as a simple, Church, Virginia inexpensive, and relatively safe way to prevent hyperbilirubinemia in premature infants. Correspondence: Laura A. Stokowski, MS, RN, 8317 Argent Circle, Fairfax Station, VA 22039 ([email protected]). NORMAL BILIRUBIN METABOLISM Copyright © 2011 by The National Association of Neonatal Nurses Humans continuously form bilirubin, and newborn DOI: 10.1097/ANC.0b013e31822ee62c infants produce relatively more bilirubin than any

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FIGURE 1. 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.3 Reprinted Miss Jean Ward, in 1956, with one of the earliest with permission. infants given phototherapy at Rochford General Hospital. Courtesy of BMJ Publishing Group.

essentially recycling the bilirubin load, a process called enterohepatic recirculation. Thus, babies with other age group. The typical bilirubin load of the reduced conjugation or elimination of bilirubin are newborn is quite high, 2 to 3 times that of an adult. also at risk for hyperbilirubinemia (Table 1). A more Bilirubin is a product of the normal destruction of cir- detailed explanation of newborn bilirubin metabo- culating erythrocytes (which have a shortened lifes- lism can be found in an article in the April 2002 issue pan in the newborn infant) and increased turnover of of this journal.7 cytochromes.5 Some infants have excessive bilirubin production, and a correspondingly elevated load of HOW PHOTOTHERAPY WORKS unconjugated bilirubin (Table 1). Unconjugated bilirubin is lipid-soluble and must Phototherapy converts bilirubin that is present in the be transported to the liver in the plasma, bound superficial capillaries and interstitial spaces of the reversibly to albumin.6 In the liver, bilirubin is trans- skin and subcutaneous tissues to water-soluble iso- ported across hepatic cell membranes, where it binds mers that are excretable without further metabolism to ligandin for conjugation. A liver enzyme, uridine by the liver (Figure 4). Neonatal jaundice expert diphosphoglucuronate glucuronosyltransferase, con- Maisels suggests that phototherapy is much like a jugates bilirubin, converting it to water-soluble biliru- percutaneous drug.6,8 When phototherapy illumi- bin pigments that can be excreted into the bile and nates the skin, an infusion of discrete photons of exit the body via the intestines, or, to a lesser degree, energy are absorbed by bilirubin much like a drug filtered through the kidneys (Figure 3). Bilirubin pig- molecule binds to a receptor. Bilirubin molecules in ments in the gut that are not eliminated can be reab- light-exposed skin undergo relatively quick photo- sorbed into the circulation as unconjugated bilirubin, chemical reactions—configurational isomerization,

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TABLE 1. Mechanisms of Hyperbilirubinemia

(1a) Increased Bilirubin Production (1b) Impaired Conjugation or Excretion Hemolytic disease of the newborn Inadequate or poor feeding intake • Rh isoimmunization • Prematurity (Ͻ39 weeks) • ABO incompatibility • Delayed or impaired lactogenesis • Minor blood group incompatibility • Inadequate milk transfer • Other feeding disorders Polycythemia Increased enterohepatic circulation • Intestinal obstruction • Meconium ileus • Meconium plugging • Cystic fibrosis Red blood cell enzyme disorders Hormonal deficiencies • G6PD deficiency • Hypothyroidism • Pyruvate kinase deficiency • Hypopituitarism Red blood cell membrane defects Disorders of bilirubin metabolism • Hereditary spherocytosis • Crigler-Najjar syndrome I and II • Gilbert disease • Lucey-Driscoll syndrome Birth trauma • Vacuum or instrumented delivery • Bruising • Cephalohematoma or subgaleal bleed Neonatal infection • Urinary tract infection • Sepsis Ethnicity • Asian ethnic background

structural isomerization, and photooxidation—to exchange transfusion to treat hyperbilirubinemia. form nontoxic, excretable isomers. These bilirubin Phototherapy is typically used either prophylacti- isomers have different shapes than the native isomer, cally or therapeutically. are more polar, and can be excreted from the liver • In preterm infants or those with a known into the bile without undergoing conjugation or hemolytic process, it is often used prophylacti- requiring special transport for their excretion.9 cally, to prevent a significant rise in serum Urinary and gastrointestinal elimination remain bilirubin. important to the process of reducing the bilirubin • In late-preterm and full-term infants, it is admin- load. istered at therapeutic doses to reduce excessive bilirubin levels and avoid development of WHEN IS PHOTOTHERAPY PRESCRIBED? bilirubin encephalopathy. The aim of phototherapy is to curtail rising serum The photoisomerization of bilirubin begins almost bilirubin and prevent its toxic accumulation in the instantaneously when the skin is exposed to light.8 brain, where it can cause the serious, permanent Unlike unconjugated bilirubin, the photoproducts of neurological complication known as kernicterus. these processes are not neurotoxic.8 Therefore, the most Where the technology is readily available, pho- important intervention for the severely hyperbilirubine- totherapy has nearly abolished the need for mic infant is to initiate phototherapy without delay.

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FIGURE 3.

Neonatal bilirubin metabolism. From Stokowski.7 Reprinted with permission.

THE IMPORTANCE OF DOSE Spectral Qualities The most effective light sources for degrading biliru- A robust relationship exists between the dose of pho- bin emit light in a relatively narrow wavelength totherapy and the rate of decline in serum bilirubin range (400 to 520 nanometers, or nm), with a peak of level.8 Dose of phototherapy is determined by several 460 Ϯ 10 nm.1 At these wavelengths, light penetrates key factors: the skin well and is maximally absorbed by biliru- • Spectral qualities of the light source used (wave- bin.8 Blue, green, and turquoise light (the blue-green length range and peak); spectrum) are considered the most effective, and • Intensity of the light (irradiance); some evidences suggest that given equal irradiance • Distance between the light and the infant’s skin; levels, the turquoise spectral range is more efficient • Body surface area exposed by the irradiated in reducing bilirubin than blue because of greater field or “footprint.” skin penetration.9

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way to increase irradiance is to move the light closer FIGURE 4. to the infant. Caution must be exerted when positioning halogen phototherapy lamps, which cannot be positioned closer to the infant than recommended by their manufacturers without incurring the risk for a burn.11

Exposed Body Surface Area The greater the body surface area exposed to light, the faster the decline in serum bilirubin. Many light sources used in neonatal care do not expose a sufficient area of skin to the light. The light source may have an adequate spectral irradiance in the center of the light’s footprint; however, irradiance decays significantly at the periphery of the light.12 The result is that only an insufficient proportion of the infant’s The mechanism of phototherapy. When bilirubin mol- body surface area receives effective treatment. This ecules absorb light, 2 main photochemical reactions problem can be solved by positioning the infant occur: Native 4Z, 15Z-bilirubin converts to 4Z, 15E properly within the footprint of the light or using bilirubin (also known as photobilirubin) and to lumiru- multiple light sources for coverage of at least 80% of bin. Unlike 4Z, 15Z bilirubin, photobilirubin can be the body surface13 (Figure 5). excreted via the liver without conjugation, but its The size of the exposed body surface area, along clearance is very slow and its conversion is reversible. with the level of irradiance, determines the spectral In the bowel (away from the light), photobilirubin is power of the phototherapy application, which in turn converted back to native bilirubin. Lumirubin is not influences its effectiveness.14 The larger the exposed reversible. So, although much less lumirubin than body surface and stronger the light, the higher the photobilirubin is formed, lumirubin is cleared from the spectral power. 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 COMPARING AND CONTRASTING monopyrroles and dipyrroles that can be excreted in PHOTOTHERAPY DELIVERY SYSTEMS the urine. This is a slow process and only a minor A number of different light sources are commer- contributor to the elimination of bilirubin during cially available for neonatal phototherapy. Each has phototherapy. Diagram courtesy of Mary Puchalski. its own advantages and disadvantages. Different

A popular, but mistaken belief holds that phototherapy delivers ultraviolet light. The phototherapy FIGURE 5. systems currently used for newborn infants do not emit significant amounts of ultraviolet radiation.8

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 ␮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 ␮W/cm2/nm, delivered over as much of the body surface as Two halogen spotlight are used to provide more possible. complete coverage. Note that the lights are not superimposed over the same area of skin but are Distance From Light used to provide coverage over different body surface Light intensity is inversely related to the distance areas on this large infant. between the light and the body surface. A simple

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neonatal phototherapy systems achieve vastly differ- underneath the infant. A commercially available system ent irradiance levels, and this can influence their clin- combines banks of fluorescent tubes on each side, with ical effectiveness.12 a transparent mattress containing fan-cooled fluorescent Combined phototherapy is often the treatment of bulbs (Bili-Bassinet, Natus Medical Incorporated, San choice for very preterm infants with hyperbilirubine- Carlos, California) (Figure 6). mia, because it has been shown to achieve lower serum bilirubin levels with a shorter duration of treatment, and Light-Emitting Diodes to significantly reduce exchange transfusions.15 One The gallium nitride LED is one of the most recent method frequently employed to provide combination innovations in phototherapy (Figure 7). These phototherapy is to use an overhead unit above the infant devices provide high irradiance in the blue to blue- (fluorescent bank light, gallium nitride light-emitting green spectrum without excessive heat generation.6 diode [LED], or halogen lamp) and a fiberoptic mattress Light-emitting-diode units are efficient, long-lasting,

FIGURE 6.

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

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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.

and cost-effective.1 The latest models incorporate Fluorescent Tubes amber LEDs to counteract the “blue hue” effect that Often referred to as “bank lights,” fluorescent tube can irritate caregivers.1 phototherapy devices have been around the longest (Figure 9). It is vital to realize, however, that not all Halogen Spot Lights fluorescent tubes are the same. Dramatic differences Halogen lamp sources deliver phototherapy using 1 or exist in the irradiance produced by different types of more quartz halogen bulbs (Figure 8). It is possible to fluorescent tubes, even within the same 425- to 475-nm achieve sufficient irradiance with halogen light sources; wavelength.11 Bulbs used in this type of phototherapy however, devices designed with a single lamp produce a unit include daylight, cool-white, blue, “special blue” circle of light with high irradiance only in the center. (the most effective), or a combination of these. One Halogen systems are compact and caregiver-friendly; system contains 6 blue tubes and 2 white tubes with however, quartz halogen bulbs carry the disadvantage of an optional on/off switch. Caregivers are often both- generating significant amounts of heat. Manufacturer’s ered by the blue-hue effect produced by all blue recommendations for safe maximal distance should be tubes, and the blue light can impair assessment of followed.11 A newer device that incorporates a metal infant skin color. The white light tubes in this unit can halide bulb (Giraffe SPOT PT Lite, GE Healthcare, be switched on to minimize the blue-hue effect with- Waukesha, Wisconsin) is an improvement over earlier out hindering the effectiveness of the phototherapy halogen spotlights. The light source is located in a light treatment. box, away from the infant, resulting in a cooler light sur- Fluorescent tube units are often positioned too rounding the infant. This high-intensity light is transmit- far away from the infant to be effective. They should ted through a light pipe in a flexible gooseneck that can be positioned as close to the infant as possible.8 be adjusted for maximum light footprint. Maisels recommends that these units be placed 10 cm

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FIGURE 8. FIGURE 9.

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

above nude full-term infants in bassinets for effective phototherapy. This method achieves an irradiance of 50 ␮W/cm2 while maintaining normal body temper- ature8 and has been successfully implemented in B jaundiced infants 37 or more weeks’ gestation.16 Phototherapy systems that incorporate fluorescent Fiberoptic Blankets tubes. Conventional bank lights (A) can be positioned Fiberoptic devices contain a tungsten-halogen bulb over an infant in a bassinet or incubator. Courtesy of that delivers light via a cable into a plastic pad con- Olympic Medical. An overhead system that combines taining fiberoptic fibers (Figure 10). The pad blue and white tubes is both effective and caregiver remains cool and can be placed directly under an friendly (B). Courtesy of Draeger Medical. With the infant to increase the skin surface area that is BiliBed (C), the infant lays on a soft mattress of fluo- exposed. The pad can also be wrapped around the rescent tubes, receiving high-intensity phototherapy infant’s midsection to provide phototherapy while from below. Courtesy of Medela, Inc. the infant is being held. Because the spectral power of the pad alone is low, it is commonly used in con- junction with overhead lights to provide double Ensure Effective Irradiance phototherapy. Position phototherapy lamps or mattresses to provide the most complete skin exposure possible. Light NURSING CARE OF THE INFANT sources should be as close to the infant as possible, RECEIVING PHOTOTHERAPY with the exception of halogen-lamp phototherapy units. Overhead units that incorporate rubberized feet Phototherapy is much more than just switching on a to rest on the incubator surface should be lowered light. The efficiency with which phototherapy achieves until they are in contact with the top of the incubator. a decline in serum bilirubin level is in large part deter- Periodic checks of spectral irradiance produced by mined by nursing care. Appropriate nursing care also different phototherapy units should be conducted to minimizes the potential side effects and complications ensure adequate irradiance delivery.11 Irradiance is of phototherapy. measured with a radiometer, an instrument that

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FIGURE 10. FIGURE 12.

Fiberoptic blanket phototherapy system. Courtesy of GE Healthcare. Properly positioned phototherapy eye shields.

gauges light in the effective wavelength for phototherapy (Figure 11). Measurements do vary among deliver more efficient phototherapy than a single different radiometers; use the instrument recom- unit, probably through improved skin coverage. mended by the manufacturer of the corresponding However, no standard definitions of “single,” “dou- phototherapy system. ble,” and “triple” phototherapy describe photother- Measured irradiance can vary widely depending apy dosages in terms of target irradiance levels. on where the measurement is taken.11 Irradiance in the center of the illuminated area can be double that Provide Eye Protection 11 of the periphery. It is preferable to take several Opaque eye shields must be used during photother- measurements in the illuminated area at infant skin apy to protect the infant’s eyes from retinal damage level and average them for a determination of overall (Figure 12). To adequately block the transmission of 8 effective irradiance. light, carefully apply eye coverings by first closing the It is fairly common to see terms such as “single,” infant’s eyes and then applying shields securely. “double,” and “triple” used in orders prescribing Avoid eye patches that are too tight, as they may phototherapy. Such terms refer only to how many apply undue pressure to the infant’s delicate eye. Turn pieces of equipment should be used to deliver pho- off the phototherapy unit and remove eye patches totherapy, and not to a specific target dose, or irradi- periodically to assess eyes for drainage, edema, and ance level. In other words, “single phototherapy” is evidence of infection, to provide visual stimulation, 1 phototherapy unit, “double” is 2 units, and so forth. and to encourage parent-infant interaction as appro- Naturally, it is hoped that 2 phototherapy units will priate on the basis of the infant’s clinical status. Complications of using eye patches include apnea (from displaced eye patches obstructing the nares), FIGURE 11. 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, start- ing with the inner canthus of the eye and moving out- ward 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 Using a radiometer to measure irradiance level during necessary to remove diapers or boundary materials phototherapy. used for postural support while providing phototherapy. Removing diapers and nesting materials around

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jaundiced, low-risk preterm infants weighing more verted back to unconjugated bilirubin if they are not than 1500 g at birth does not shorten the length of eliminated in the stool.6 Enteral feeding is essential treatment.18 It is not known, however, whether dia- to promote stooling in hyperbilirubinemic infants. pers and/or boundary materials affect the bilirubin Lumirubin, an irreversible product of structural iso- decline in smaller, less mature infants or in larger, merization of bilirubin, is excreted in the urine as more mature infants with severe hyperbilirubinemia. well as in the bile, so an adequate urine output is also The American Academy of Pediatrics recom- important. An ongoing assessment of the infant’s mends removing diapers for intensive phototherapy, urine output is an important measure not only of when the serum bilirubin is approaching exchange hydration but also of elimination of bilirubin. The transfusion level.11 Light-permeable diapers are also infant’s urine may appear dark in color as bilirubin commercially available (BiliBottoms, CAS Medical elimination increases. Systems, Inc, Branford, Connecticut). Watery stools and diarrhea have been observed in infants undergoing phototherapy. These characteris- Proper Positioning tic dark greenish stools are related to the increased Frequent turning to expose different areas of skin has excretion of unconjugated bilirubin from the intes- not been shown to improve the effectiveness of con- tines.6 Protective skin care is necessary to prevent ventional (single) phototherapy.19-21 perianal skin breakdown from watery stools. One study actually reported that the serum bilirubin levels of infants maintained in a supine position Hydration without turning declined significantly faster than Several studies have documented an increase in those of infants who were turned prone/supine every transepidermal water loss during phototherapy.24,25 2 to 3 hours.20 Excessive fluid losses via the skin are of particular concern in the smallest, most immature infants dur- Assess and Adjust Thermoregulation Devices ing the first week of life. These losses can be exacer- Some phototherapy units can cause a significant bated by phototherapy, although insensible water increase in the infant’s body temperature.22 When losses are not as high with fiberoptic or LED pho- phototherapy is directed over an incubator, immedi- totherapy devices.5 Increasing fluid intake has been ate and sustained fluctuations can occur in the thermal shown to shorten the duration of phototherapy in environment.23 Thermal instability can occur when full-term neonates.26 Some infants may experience using either the skin- or air-control mode of the incu- intestinal fluid losses from a high volume of loose bator. With inadequate monitoring, vigilance, and stools during phototherapy. Although it is important adjustments to the thermal environment, the infant to maintain adequate hydration, routine supplemen- can easily develop hypothermia or hyperthermia tation with intravenous fluids is not recommended.6 during phototherapy. For breastfed infants with evidence of dehydration, When phototherapy is initiated during air control supplementation with a milk-based formula inhibits mode, a rapid rise in body temperature usually neces- the enterohepatic circulation of bilirubin and may sitates a downward adjustment in the air temperature improve the efficacy of phototherapy.6 set point. When phototherapy is discontinued, the air Maintaining fluid balance by increasing incubator temperature set point may require an upward read- humidity might also be counterproductive, especially justment to compensate for the loss of heat from the if high levels of humidity are used. A recent study27 phototherapy lights. found that when humidification was set at more than During skin control mode, the air temperature usu- 90%, irradiance delivery from an LED phototherapy ally drops when phototherapy is initiated because the unit was reduced by 15% and that from a halogen additional heat warms the infant, and less environmen- phototherapy unit by 45%. The mist and water con- tal heat support is required. Using skin control mode densation within the incubator are postulated to is generally preferred during phototherapy because interfere with irradiance delivery. this automatic compensatory mechanism keeps the infant’s body temperature within normal limits as long Promoting Parent-Infant Interactions as the lights remain on. However, if the lights are Phototherapy necessarily separates the neonate from turned off abruptly, the infant’s temperature can also its mother and may interfere with the process of estab- drop precipitously. It will then take some time for the lishing lactation. Unless jaundice is severe, photother- air temperature to rise again and rewarm the infant. apy can be safely be interrupted at feeding time to allow continuation of breastfeeding, parental visits, Promoting Elimination and Skin Integrity and skin-to-skin care.6 Remove the eye patches during The photoproducts of bilirubin require elimination these visits. If the serum bilirubin level is approaching from the body in the stool or urine. Some of the pho- the exchange transfusion threshold, and/or if the tochemical reactions induced by phototherapy are infant has escalating pathologic jaundice, photother- reversible, meaning that the isomers can be con- apy should be continuously maintained.6

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Monitoring Bilirubin Levels Intensive phototherapy may have another, even The most significant decline in bilirubin level occurs more important benefit in an infant with a bilirubin in the first 4 to 6 hours after initiating phototherapy. level high enough to increase the risk for neurologi- Conventional (single) phototherapy can decrease the cal damage.36 Almost as soon as the lights are serum bilirubin by up to 22% in the first 24 hours of switched on, the process of isomerization of bilitubin treatment. Double phototherapy can produce a fall of begins, converting bilirubin molecules into more as much as 29% in the first 24 hours,28 and intensive polar photoisomers, that are unable to cross the phototherapy can lower the bilirubin level by as blood-brain barrier independently to gain access to much as 5 mg/dL/h (85 ␮mol/L/h) In infants with the neurons.35 Well before a measurable decline in rapidly rising bilirubin levels, stabilizing the bilirubin serum bilirubin occurs, the effects of phototherapy level or slowing its rate of rise should be considered are believed to protect the brain from the neurotoxic valid measures of the success of therapy.29 effects of bilirubin, although no studies have yet Phototherapy lamps must be turned off while proved this hypothesis. drawing blood samples for serum bilirubin testing, because the lights will act on the bilirubin pigments LIMITATIONS OF HOME PHOTOTHERAPY in the blood sample, causing the bilirubin level to AND SUNLIGHT decline, thereby providing erroneous data to the care team.3 Transcutaneous bilirubinometry can also be The irradiance and surface area exposure produced used for the evaluation of bilirubin levels in infants by home phototherapy units are lower than those pro- receiving phototherapy by using the unexposed skin duced by typical hospital units11 making them less effi- of the forehead, under the infant’s eye patches, for cient at lowering the serum bilirubin level. Whether a these measurements.30 valid indication for home phototherapy exists is ques- After discontinuing phototherapy the bilirubin tionable; current guidelines state that a bilirubin high level often rises slightly, a phenomenon known as enough to warrant treatment should be managed in “rebound.” Rebound hyperbilirubinemia is usually an the hospital.11 In the past, parents have sometimes elevation of no more than 1 to 2 mg/dL31,32; however, been told to expose their jaundiced infants to sunlight. postphototherapy rebound to clinically significant Notwithstanding phototherapy’s beginnings in the levels can occur.33 Infants at greatest risk of significant sunny courtyard of an English hospital, this practice is postphototherapy rebound in serum bilirubin levels not considered a safe or reliable way to treat jaun- requiring closer follow-up include the following: dice.11 There are reports in the literature of infants developing kernicterus after their parents were • Premature infants; instructed to treat their infants’ jaundice at home by • Infants with ongoing hemolysis (ie, positive exposing them to sunlight, in some cases for as little as direct Coombs tests); 15 minutes per day.37 Not only was this very likely to • Infants treated before 72 hours of age.33 be ineffective but also it probably contributed to A serum bilirubin measurement obtained 24 hours delays in recognition of the severity of the hyperbiliru- after discontinuation of phototherapy will detect binemia as well as delays in proper treatment. rebound hyperbilirubinemia.32 ADVERSE EFFECTS OF PHOTOTHERAPY INDICATIONS FOR INTENSIVE PHOTOTHERAPY The most noticeable clinical complication of phototherapy is “bronze baby syndrome,” a grayish-brown When an infant’s serum bilirubin is rising rapidly or discoloration of the skin that occurs exclusively in approaching exchange transfusion level, intensive infants with cholestatic jaundice.11 Bronze baby phototherapy must be instituted at maximal spectral syndrome is believed to occur when the brown pho- power. This entails delivering high levels of irradi- toproducts of porphyrins, especially copper por- ance (usually 30 ␮W/cm2/nm or higher) to as much phyrins, accumulate in the skin and their excretion is of the infant’s surface area as possible.1 The most effi- impaired by cholestasis.5 Phototherapy can damage cient phototherapy units available should be used, red-blood-cell membranes, increasing their suscepti- and they should be positioned for maximum skin bility to lipid peroxidation and hemolysis.1 These coverage. In these situations, additional surface-area effects may contribute to the pathogenesis of disor- exposure can be achieved by removing the infant’s ders common in the very low-birth-weight infant, diaper and lining the sides of the bassinet, incubator, including bronchopulmonary dysplasia, retinopathy or radiant warmer with light-reflecting material such of prematurity, and necrotizing enterocolitis.1 aluminum foil or white linens.34 Intensive photother- Phototherapy has been associated with patency of the apy can produce a decline in serum bilirubin of as ductus arteriosus38 and ileus in very low-birth-weight much as 10 mg/dL within a few hours in severely infants,39 as well as retinopahty of prematurity.40 hyperbilirubinemic infants.35 Recent evidence also suggests that phototherapy

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impairs immune system function through alterations 14. Hansen TW. Twists and turns in phototherapy for neonatal jaundice. Acta Paediatr. 2010;99:1117-1118 41 of cytokine production. Phototherapy has been 15. Romagnoli C, Zecca E, Pappaci P, Vento G, Girlando P, Latella C. Which pho- linked to the development of abnormal melanocytic totherapy system is most effective in lowering serum bilirubin in very preterm infants? Fetal Diagn Ther. 2006;21:204-209. nevi when the children become older. The evidence 16. Walker L, Vroman L, Becker J, Anderson F. Open crib phototherapy: using for this association is not definitive and has been evidence to change practice. Nurs Womens Health. 2007;11:402-404. 17. Fok TF, Wong W, Cheng AF. Use of eye patches in phototherapy: effects on debated, but at this time, this possible effect cannot be conjunctival bacterial pathogens and conjunctivitis. Pediatr Infect Dis J. ruled out.42 Although it is not always possible to sepa- 1995;14:1091-1094. 18. Pritchard MA, Beller EM, Norton B. Skin exposure during conventional rate the effects of phototherapy from the effects of phototherapy: a randomized controlled trial. J Paediatr Child Health. 2004; hyperbilirubinemia itself, recent research has impli- 40:270-274. cated phototherapy as a risk factor for childhood 19. Chen C, Liu S, Lai C, Hwang C, Hsu H. Changing position does not improve the efficacy of conventional phototherapy. Acta Paediatr Tw. 2002;43:255- 43 asthma. Other rare side effects include purpura and 258. bulbous eruptions, which can occur in infants with ele- 20. Shinwell ES, Sciaky Y, Karplus M. Effect of position changing on bilirubin levels during phototherapy. J Perinatol. 2002;22:226-229. vated direct bilirubin. Phototherapy is contraindicated 21. Donneborg ML, Knudsen KB, Ebbesen F. Effect of infants’ position on serum in infants with congenital erythropoietic porphyria, bilirubin level during conventional phototherapy. 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