Atlas of Procedures in Neonatology, 4th Edition

Miscellaneous Procedures

46

Phototherapy

Sepideh Nassabeh-Montazami

Phototherapy is the most common therapeutic intervention used for the treatment of hyperbilirubinemia (1). The process of phototherapy causes three reactions: photo-oxidation, configurational and structural isomerization of the bilirubin molecule, leading to polar, water-soluble photoproducts that can be excreted in bile and urine without the need for conjugation or further metabolism (2).

The aim of phototherapy is to reduce serum bilirubin levels in order to decrease the risk of acute bilirubin encephalopathy and the more chronic side effect of bilirubin toxicity, kernicterus (3).

  1. Indications
  2. Clinically significant indirect hyperbilirubinemia. Indications to start phototherapy in babies with hyperbilirubinemia can vary depending on gestational age, birthweight, hours of life, presence of hemolysis, and other risk factors such as acidosis and sepsis (3,4).
  3. The total serum bilirubin(TSB) level must be considered when making the decision to commence treatment, as there is significant variability in laboratory measurement of direct bilirubin levels.
  4. The American Academy of Pediatrics has published clinical practice guidelines for phototherapy in newborn infants at 35 weeks' or more gestation (3) (Fig. 46.1).
  5. These guidelines do not apply to preterm infants less than 35 weeks' gestation. Preterm infants are at higher risk of developing hyperbilirubinemia compared to term infants. The decision to initiate phototherapy in this group of infants remains variable and highly individualized. The management of hyperbilirubinemia in extremely preterm and low-birthweight infants has been recently reviewed (4,5) (Table 46.1).
  6. Prophylactic phototherapy, often used for preterm infants with skin bruising, is ineffective until bilirubin appears in the skin.
  7. Contraindications
  8. Congenital porphyria or a family history of porphyria is an absolute contraindication to the use of phototherapy. Severe purpuric bullous eruptions have been described in neonates with congenital erythropoietic porphyria treated with phototherapy (6).
  9. Concomitant use of drugs or agents that are photosensitizers is also an absolute contraindication (7).
  10. Concurrent therapy with metalloporphyrin heme oxygenase inhibitors has been reported to result in mild transient erythema (8).
  11. Although infants with cholestatic jaundice may develop the “bronze baby syndrome” when exposed to phototherapy (see Complications), the presence of direct hyperbilirubinemia is no longer considered to be a contraindication (3). However, because the products of phototherapy are excreted in the bile, the presence of cholestasis may decrease the effectiveness of phototherapy.
  12. Equipment

In order to have an understanding of the equipment available for phototherapy, it is necessary to be familiar with the terminology involved.

  1. Spectral qualitiesof the delivered light (wavelength range and peak). Bilirubin absorbs visible light within the wavelength range of 400 to 500 nm, with peak absorption at 460 ± 10 nm considered to be the most effective (2).
  2. Irradiance(intensity of light), is expressed as watts per square centimeter (W/cm2). This refers to the number of photons received per square centimeter of exposed body surface area.
  3. Spectral irradianceis irradiance that is quantitated within the effective wavelength range for efficacy and is expressed as µW/cm2/nm (9). This is measured by various commercially available radiometers. Specific radiometers are generally recommended for each phototherapy system, because measurements of irradiance may vary depending on the radiometer and the light source (3).

A variety of phototherapy equipment devices exist and may be free-standing, attached to a radiant warmer, wall-mounted, suspended from the ceiling, or fiber-optic systems. These in turn may contain various light sources to deliver the phototherapy, which may be categorized as:

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FIG. 46.1. Guidelines for phototherapy in hospitalized infants of 35 or more weeks' gestation. (From American Academy of Pediatrics Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004;114:297–316.)

  1. Fluorescent tubes
  2. Halogen bulbs
  3. Fiber-optic light combinations used in pads, blankets, or spotlights
  4. High-intensity light-emitting diodes

The clinician is therefore faced with a vast array of equipment to choose from and must be aware of advantages and disadvantages of each type.

TABLE 46.1 Guidelines for Use of Phototherapy and Exchange Transfusion in Preterm Infants Based on Gestational Age

Gestational Age (wk)

Total Bilirubin Level (mg/dL/µmol/L)

 

Exchange Transfusion

 

Phototherapy

Sicka

Well

36

14.6 (250)

17.5 (300)

20.5 (350)

32

8.8 (150)

14.6 (250)

17.5 (300)

28

5.8 (100)

11.7 (200)

14.6 (250)

24

4.7 (80)

8.8 (150)

11.7 (200)

aRhesus disease, perinatal asphyxia, hypoxia, acidosis, hypercapnea.
Source: Maisels MJ, Watchko JF. Treatment of jaundice in low birthweight infants. Arch Dis Child Fetal Neonatal Ed. 2003;88:F459–F463.

  1. Fluorescent tubes
  2. “Special blue” tubes, such as F20 T12/BB, provide more irradiance in the blue spectrum than other tubes and are the most effective fluorescent light source. (2) (Fig. 46.2). The “special blue F20 T12/BB” tubes provide much greater irradiance than regular blue tubes, labeled F20T12/B. The flickering glare of the blue light has been reported

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to cause giddiness, nausea, and temporary blurring of vision in nursing personnel (10). One way to overcome this has been to use cool white light in conjunction with the special blue, but this combination can decrease efficacy by as much as 50%, depending on the proportion of cool white light used (11).

 

FIG. 46.2. Relative spectral content of phototherapy bulbs. Shaded area indicates wavelength effective for phototherapy. Absolute spectral irradiance (µW/cm2/nm) depends not only on relative power across wavelength of bilirubin absorption but also on total wattage and distance from infant. Although all bulbs provide effective phototherapy for the same wattage, “special blue” and blue fluorescent bulbs provide the most amount of power in the bilirubin wavelength. (Based on data from 

Olympic Medical (a–d); from Warshaw JB, Gagliardi J, Patel A. A comparison of fluorescent and nonfluorescent light sources for phototherapy. Pediatrics. 1980;65:795–798

 (e); and from 

Farr PM, Diffey BL. The colour of light for neonatal phototherapy.Arch Dis Child. 1988;63:461–462

 (f).

  1. Green/turquoise lamps penetrate the skin to a greater depth, but the advantage over blue light remains debated (12,13 and 14).
  2. Cool white lamps may be inadequate in sufficiently decreasing total bilirubin levels unless the lights are positioned in close proximity to the infant (11). As mentioned above, this type of light has also been used together with special blue tubes.
  3. Daylight lamps, like cool white lamps, have a wider wavelength spectrum and are less effective than blue light (11).
  4. Halogen lamps
  5. Halogen spotlight systems utilize single or multiple metal halide lamps as the light source and can provide high irradiance over a small surface area (>20 µW/cm2/nm).
  6. These units can generate considerable heat, with the potential of causing thermal skin injury; therefore, they must not be in close proximity to the patient.
  7. The variable positioning with respect to the distance from the infant as well as heterogeneity of the irradiance can lead to unreliable dosing and unpredictable clinical responses. In addition, they are more expensive than fluorescent bulbs (2).
  8. Fiber-optic systems
  9. UV-filtered light from a tungsten–halogen bulb enters a fiber-optic cable and is emitted from the sides and end of fiber-optic fibers inside a plastic pad.

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  1. The pad emits insignificant levels of heat, so it can be placed in direct contact with the infant to deliver up to 35 µW/cm2/nm of spectral irradiance, mainly in the blue–green range (2,15).
  2. The orientation of the fiber-optic fibers determines the uniformity of emission and is unique to each of the commercially available devices.
  3. The main advantages of these systems are that, while receiving phototherapy, the infant can be held and/or nursed, thereby minimizing infant/parent separation. In addition, covering the infant's eyes is not necessary, preventing further parental anxiety.
  4. The main disadvantage of the fiber-optic pads is that they cover a relatively small surface area, and therefore have less efficacy compared to overhead sources. They should not be used as the sole means of providing phototherapy in an infant with significant hyperbilirubinemia (2,3,10).
  5. These devices are often used as an adjunct to conventional overhead application of phototherapy to provide “double” phototherapy (circumferential phototherapy), which has greater efficacy because greater body surface area is exposed to the light (15).

Two examples of fiber optic systems are

  1. The Wallaby 3 Phototherapy System (Respironics, Norwell, MA, USA) delivers light at a wavelength of 425 to 475 nm with an average irradiance of 8 to 10 µW/cm2/nm. Two sizes of fiber-optic light panels are available: a 4-in x 5-in neonatal panel and a 3-in x 14-in wrap-around panel, which may be wrapped around the infant.
  2. The Homed BiliBlanket Phototherapy System (Ohmeda Medical, Laurel, MD, USA) delivers light at a wavelength of 400 to 550 nm; the intensity of light delivered can be controlled, permitting irradiance levels of 15, 25, and 35 µW/cm2/nm. The fiber-optic panel consists of 2,400 fibers woven into a mat measuring 10 x 20 cm.
  3. Gallium nitride light-emitting diodes (LEDs)
  4. These systems are semiconductor phototherapy devices capable of delivering high spectral irradiance levels of >200 µW/cm2/nm with very little generation of heat within a very narrow emission spectrum in the blue range (460 to 485 nm) (16,17).
  5. LEDs have a longer lifetime (>20,000 hours) and have become cost-effective for use in phototherapy devices.
  6. An example of an LED system is the neoBLUE System (Natus Medical, San Carlos, CA, USA). This device delivers blue light in the range of 450 to 470 nm with either a low-intensity (12 to 15 µW/cm2/nm) or a high-intensity (30 to 35 µW/cm2/nm) setting.
  7. Technique (Conventional Phototherapy)

Intensive phototherapy is defined as the use of light in the 430- to 490-nm band delivered at 30 µW/cm2/nm or higher to the greatest body surface area possible (3).

  1. Position phototherapy unit over infant to obtain desired irradiance (10 to 40 µW/cm2/nm). Maximal amount of irradiance achieved by standard technique is generally 30 to 50 µW/cm2/nm. The distance of the light from the infant has a significant effect on the intensity of phototherapy, and to achieve maximal intensity, the lights should be positioned as close as possible to the infant. Fluorescent tubes may be brought within approximately 10 cm of term infants without causing overheating, but halogen spot phototherapy lamps should not be positioned closer to the infant than recommended by the manufacturer, because of the risk of burns (3,18).
  2. If increased irradiance is required, add additional units or place a fiber-optic phototherapy pad under the infant (15). Additional surface area may be exposed to phototherapy by lining the sides of the bassinet with aluminum foil or a white cloth (19).
  3. Keep the photoradiometer calibrated and perform periodic checks of phototherapy units to make sure that adequate irradiance is being delivered (3).
  4. Maintain an intact Plexiglas shield over phototherapy light bulbs in order to block ultraviolet radiation and to protect the infant from accidental bulb breakage.
  5. Provide ventilation to the phototherapy unit to prevent overheating light bulbs.
  6. Maintain cleanliness and electrical safety.
  7. Technique (Fiber-Optic Phototherapy)

Fiber-optic phototherapy can be used as the sole source of phototherapy or as an adjunct to conventional treatment.

  1. Insert panel into disposable cover so that it is flat and directed toward infant.
  2. Place covered panel around infant's back or chest and secure in position. Phototherapy blanket/pad must be positioned directly next to the infant's skin to be effective.

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Avoid constriction and skin irritation under the infant's arms if the panel is wrapped around the infant.

  1. Discard disposable covers after each treatment and when soiled.
  2. Use eye patches if there is any direct exposure to lights in panel or if used with conventional phototherapy for double-sided effect.
  3. Ensure stability and adequate ventilation of illuminator unit by placing on a secure surface.
  4. Connect fiber-optic panel to illuminator.
  5. Keep fiber-optic panel and illuminator clean and dry.
  6. Allow lamp to cool for 10 to 20 minutes before moving illuminator. Do not place sharp or heavy objects on panel or cable.

Care of the Infant Receiving Phototherapy

  1. Monitor temperature, particularly of infants in an incubator, who may develop hyperthermia.
  2. Monitor intake, output, and weight. Fluid supplementation may be necessary secondary to increased insensible losses and frequent stooling. Encourage breast feeding. Healthy term breast-fed infants may be supplemented with milk-based formula if maternal milk supply is inadequate. Intravenous fluids are rarely required. Milk feeding inhibits the enterohepatic circulation of bilirubin (3).
  3. The use of eye protection in the form of eye patches is necessary for infants receiving overhead phototherapy. Masks adhering directly to Velcro tabs on the temples are preferable to circumferential headbands.
  4. Maximize skin exposure to phototherapy source by using the smallest possible diapers as well as keeping blanket rolls from blocking light.
  5. Avoid fully occlusive dressings, bandages, topical skin ointments, and plastic in direct contact with the infant's skin, to prevent burns.
  6. Remove plastic heat shields and plastic wrap that decrease irradiance delivered to the skin (20).
  7. If in use, shield the oxygen saturation monitor probe from the phototherapy light.
  8. Encourage parents to continue feeding, caring for, and visiting their infant.
  9. Home Phototherapy

Home phototherapy decreases costs of hospitalization and eliminates separation of mother and infant. It is safe and effective for selected infants. Home phototherapy should be used only in infants whose bilirubin levels are in the “optional phototherapy” range (Fig. 46.1).

  1. Make arrangements to measure infant's serum bilirubin every 12 to 24 hours, depending on the previous concentration and rate of rise. The infant should be examined daily by a visiting nurse or at an office.
  2. The supervising physician should be in contact with the family daily during the period of treatment.
  3. The infant should be rehospitalized if he or she shows signs of illness or if the serum bilirubin concentration exceeds 18 mg/dL.

Efficacy of Phototherapy

The therapeutic efficacy of phototherapy depends on several factors.

  1. Exposed body surface area: The greater the area exposed, the greater the rate of bilirubin decline
  2. Distance of the infant from the light source
  3. Skin thickness and pigmentation
  4. Total bilirubin at clinical presentation
  5. Duration of exposure to phototherapy
  6. Discontinuation of Phototherapy and Follow-Up
  7. There is no standard for discontinuing phototherapy. The total serum bilirubin (TSB) level that determines the discontinuation of phototherapy depends on the age at which treatment was initiated and the etiology of hyperbilirubinemia (3,21).
  8. For infants who are readmitted to hospital (usually for TSB levels of 18 mg/dL or higher), phototherapy may be discontinued when the serum bilirubin level falls below 13 to 14 mg/dL.
  9. For infants who are readmitted with hyperbilirubinemia and then discharged, significant rebound is uncommon, but may still occur. In cases of prematurity, positive direct antiglobulin (Coombs) test, and for babies treated less than 72 hours, the likelihood of rebound is much higher, and these risk factors should be taken into account when planning postphototherapy follow-up (22,23 and 24). Generally, a follow-up bilirubin measurement within 24 hours after discharge is recommended (3).
  10. Complications of Phototherapy

“Phototherapy has been used in millions of infants for more than 30 years, and reports of significant toxicity are exceptionally rare” (3).

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Complications include the following.

  1. “Bronze baby syndrome” occurs in some infants with cholestatic jaundice who are exposed to phototherapy, as a result of accumulation in the skin and serum of porphyrins. The bronzing disappears in most infants within 2 months (25). Rare complications of purpuric eruptions due to transient porphyrinemia have been described in infants with severe cholestasis who receive phototherapy (26).
  2. Diarrhea or loose stools (27)
  3. Dehydration secondary to insensible water loss
  4. Skin changes ranging from minor erythema, increased pigmentation, and skin burns to rare and more severe blistering and photosensitivity in infants with porphyria and hemolytic disease
  5. Potential retinal damage from light exposure if eye patches are not used effectively (28).
  6. Separation of mother and infant and interference with bonding.

References

  1. Vreman HJ, Wong RJ, Stevenson DK.Phototherapy: current methods and future directions. Semin Perinatol. 2004;28:326–333.
  2. McDonagh AF, Lighter DA.Phototherapy and the photobiology of bilirubin. Semin Liver Dis. 1988;272–283.
  3. American Academy of Pediatrics Subcommittee on Hyperbilirubinemia.Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004;114:297–316.
  4. Maisels MJ, Watchko JF.Treatment of jaundice in low birthweight infants. Arch Dis Child Fetal Neonatal Ed. 2003;88: F459–F463.
  5. Cashore WJ.Bilirubin and jaundice in the micropreemie. Clin Perinatol. 2000;27:171–179.
  6. Soylu A, Kavukcu S, Turkmen M.Phototherapy sequela in a child with congenital erythropoietic porphyria. Eur J Pediatr.1999;158:526–527.
  7. Kearns GL, Williams BJ, Timmons OD.Fluorescein phototoxicity in a premature infant. J Pediatr. 1985;107:796–798.
  8. Valaez T, Petmezaki S, Henschke C, et al. Control of jaundice in preterm newborns by an inhibitor of bilirubin production: studies with tin-mesoporphyrin. Pediatrics.1994; 93:1–11.
  9. Maisels MJ.Phototherapy: traditional and nontraditional. J Perinatol. 2001(suppl 1):S93–S97.
  10. Sarici SU, Alpay F, Unay B, et al. Comparison of the efficacy of conventional special blue light phototherapy and fiberoptic phototherapy in the management of neonatal hyperbilirubinemia. Acta Paediatr.1999;88:1249–1253.
  11. De Carvalho MDe Carvalho D, Trzmielina S, et al. Intensified phototherapy using daylight fluorescent lamps. Acta Pediatr.1999;88:768–771.
  12. Ebbesen F, Agati G, Pratesi R.Phototherapy with turquoise versus blue light. Arch Dis Child Fetal Neonatal Ed. 2003;88: F430–F431.
  13. Seidman DS, Moise J, Ergaz Z.A prospective randomised controlled study of phototherapy using blue and blue-green light emitting devices and conventional halogen quartz phototherapy. J Perinatol. 2003;23:123–127.
  14. Roll EB, Christensen T.Formation of photoproducts and cytotoxicity of bilirubin irradiated with turquoise and blue phototherapy light. Acta Pediatr. 2005;94:1448–1454.
  15. Tan KL.Comparison of the efficacy of fiberoptic and conventional phototherapy for neonatal hyperbilirubinemia. J Pediatr.1994;125:607–612.
  16. Vreman HJ, Wong RJ, Stevenson DK, et al. Light emitting diodes: a novel light source for phototherapy. Pediatr Res.1998;44: 804–809.
  17. Seidman DS, Moise J, Ergaz Z, et al. A new blue light emitting phototherapy device: a prospective randomized controlled study. J Pediatr.2000;136:771–774.
  18. Maisels MJ.Why use homeopathic doses of phototherapy. Pediatrics. 1996;98:283–287.
  19. Eggert P, Stick C, Schroder H.On the distribution of irradiation intensity in phototherapy. Measurements of effective irradiance in an incubator. Eur J Pediatr. 1984;142:58–61.
  20. Kardson J, Schothorst A, Ruys JH, et al. Plastic blankets and heat shields decrease transmission of phototherapy light. Acta Paediatr Scand.1986;75:555.
  21. Maisels MJ, Kring E.Bilirubin rebound following intensive phototherapy. Arch Pediatr Adolesc Med. 2002;156:669–672.
  22. Yetman RJ, Parks DK, Huseby V, Garcia J.Rebound bilirubin levels in infants receiving phototherapy. J Pediatr. 1998;133: 705–707.
  23. Lazar L, Litwin A, Merlob P.Phototherapy for neonatal nonhemolytic hyperbilirubinemia. Analysis of rebound and indications for discontinuing phototherapy. Clin Pediatr (Phila.). 1993;32:264–267.
  24. Kaplan M, Kaplan E, Hammerman C, et al. Post phototherapy neonatal rebound: a potential cause of significant hyperbilirubinemia.Arch Dis Child.2006;91:31-–34.
  25. Rubaltelli F, Da Riol R, D'Amore ES, et al. The bronze baby syndrome: evidence of increased tissue concentration of copper porphyrins. Acta Pediatr.1996;85:381–384.
  26. Paller AS, Eramo LR, Farrell EE, et al. Purpuric phototherapy induced eruption in transfused neonates: relation to transient porphyrinemia. Pediatrics.1997;100:360–364.
  27. DeCurtis M, Guandalini S, Fasano A, et al. Diarrhea in jaundiced neonates treated with phototherapy: role of intestinal secretion.Arch Dis Child.1989:64:1161–1164.
  28. Bhupathy K, Sethupathy R, Pildes RS.Electroretinography in neonates treated with phototherapy. Pediatrics. 1978;61: 76–81.