14 V O L U M E 1 I S S U E 1 2 0 0 5 infant

P H O T O T H E R A P Y D E V I C E S

Physiological jaundice is a normalprocess seen in 45-60% of termnewborns during the first few days of life.Pathological jaundice arises from factorswhich alter the usual processes involved inbilirubin metabolism. Hyperbilirubin-aemia needing treatment may arise fromphysiological or pathological causes1.Jaundice appearing within 24 hours ofbirth or after 14 days is considered to beoutside the normal process andpathologic2. Very early jaundice may bedue to blood group incompatibility andlate jaundice may be a result of metabolicor endocrine disorders, for examplehyperthyroidism or Criglar-Najjar disease.

Neonatal phototherapy has its origins inthe observations of a nurse on the effect ofsunlight on jaundiced babies skin colour.From further experiments and obser-vations it was found that the bilirubinmolecule, responsible for the yellow skincolour of jaundiced babies, was mostsensitive to light in the blue and blue-greenregions of the visible spectrum3,4. Theaction of light on bilirubin is notcompletely understood but there are manyin-depth explanations of the currentunderstanding5,6. Prototype and commercialphototherapy devices followed the discoveryof the effect of light on jaundiced babies andthere are now many different commercialdevices available. Clinical workers haveidentified three important criteria foreffective neonatal phototherapy: effectivespectrum, sufficiently high irradiance andlarge effective treatment area7. Eight of thedevices commercially available andcurrently in use in the NHS have beenevaluated by the Medicines and Healthcareproducts Regulatory Agency (MHRA)formerly the Medical Devices Agency

(MDA). Drawing on these publishedevaluation reports this paper looks at thelight sources used, the ways in which thedevices can be used, the safety ofphototherapy and how each deviceperforms against the criteria identified bythe clinical workers.

Criteria for effective phototherapy

Effective spectrum

For phototherapy to be effective photons oflight from the lamp must be absorbed bythe bilirubin molecule. Bilirubin appearsyellow because it strongly absorbs blue andgreen light6. Blue light around 450nm isabsorbed most readily if bilirubin is in atest tube. In a baby other factors, includingskin penetration and albumin binding,combine causing a colour shift of the mosteffective light toward the blue-greenregion5,8,9. Debate over the most effectivewavelengths of light to use still producesmany research papers. Blue light has beeninvestigated intensively5,10,11 and has beenshown to be effective10. However, Pratesi etal12 proposed the use of blue-green lightand demonstrated its effectiveness13.

Irradiance

Once an effective waveband has beenfound the light available must then besufficiently intense, that is, have a highenough irradiance, to produce anappreciable effect in reducing the neonatesbilirubin level14. The Department of Health(DH) recommended a minimum level of1mW.cm-2 in 199215 but unfortunately didnot specify a waveband in which tomeasure the irradiance. As Metherall8

points out, it is impossible to comparepublished reports of irradiance because ofthe different wavebands and radiometers

Neonatal phototherapy todays lights,lamps and devices Neonatal phototherapy is a widely used and accepted form of treatment for neonatalhyperbilirubinaemia. Effective phototherapy needs to satisfy three important criteria identifiedin the literature: effective spectrum, sufficiently high irradiance and large effective treatmentarea. This article looks at how technology for delivering light therapy varies, considers the safety aspects and compares the devices available and in use in the NHS today, against theidentified effective criteria.

Stephanie D.P. Wentworth BSc(Hons), PhD, MIPEM, AMInstP, CSci Senior Clinical Engineer, Medical Physics andClinical Engineering Directorate,Rehabilitation Engineering Unit, RookwoodHospital, Llandaff, Cardiff.

Keywords

neonatal phototherapy; light spectrum;irradiance; effective light field; effectivesurface area; phototherapy devices

Key points

Wentworth, S.D.P. (2005) Neonatalphototherapy todays lights, lamps anddevices. Infant 1(1): 14-19.1. Spectrum, irradiance and effective light

field area vary between devices.2. Four basic light sources are used for

phototherapy devices.3. Not all phototherapy devices are

equally effective.4. Intensive phototherapy can be achieved

using more than one phototherapydevice.

Neonatal phototherapy 11/1/05 1:01 pm Page 14

V O L U M E 1 I S S U E 1 2 0 0 5 15infant

P H O T O T H E R A P Y D E V I C E S

that have been used to measure it. Thisproblem has been discussed severaltimes7,16. MHRA evaluation reports17-23 onphototherapy devices have maintainedconsistency by stating measured irradiancein the waveband 400nm to 550nm, whichalthough a little wide, includes all of thewavebands used by clinical workers in thefield. It is also the waveband specified inthe international standard for neonatalphototherapy devices24.

More recently, higher minimum levels ofirradiance have been proposed as morerealistic in order to provide effectivetreatment25. The irradiance of differentphototherapy devices varies widely and isdependent on a number of factors,including the number of bulbs, tubes orlight sources11, distance of the light sourcefrom the neonate7,26 and quality of thebulb/tube variation has been observed.

Effective surface area

During phototherapy as much of theneonates skin as possible should beilluminated by light of an effectivewaveband and sufficient irradiance7. Whenapplied to devices this concept may bethought of as the effective light field;effective surface area is the term used byIEC24 and DH17. The surface area of a full-term baby is approximately 2100cm2, andfor a 32 week premature baby approx-imately 1300cm2 27. A planar (horizontallyflat) overhead phototherapy lampilluminates up to one third of a babys skinsurface area, ie 700cm2 and 430cm2 for afull term and a premature baby respectively.Illuminating as much skin surface area aspossible has been shown to increase thespeed of bilirubin clearance; that is increaseit above the rate at which the bilirubin isproduced by the infant, thereby, producinga reduction in the overall bilirubin level7,28.Metherall8 also raises the importantpractical issue of the clothing worn by theinfant during phototherapy. As much ofthe neonates skin surface as possibleshould be exposed to the therapeutic light.Eye protection for the infant is veryimportant but the rest of the babysclothing should be minimal; small ortransparent nappies are sometimes used.

Types of phototherapy deviceTwo types of phototherapy devices arecurrently available: the conventionalphototherapy light which has been used forover 40 years and the fibreopticphototherapy device which has beenavailable for nearly 15 years.

Conventional phototherapy

These devices typically use one or moretungsten halogen bulb, a metal halide gasdischarge tube, long or compact (orfolded) fluorescent lamps, or most recently,light emitting diodes (LEDs). The lightsource is positioned above or below thebaby and the irradiance is dependent onthe distance between the baby and the

lights. The relationship is related to theinverse square law, that is, the intensity oflight decreases as the square of thedistance. For example; the irradiance at adistance of two metres will only be aquarter of the irradiance at one metre froma light source. However, the relationship inreality is more complex than this and thedecrease in irradiance with distance tendsto be less because the light is rarely a pointsource29. Obviously the closer the lights canbe positioned to the infant the higher theirradiance, but care must be taken with thesafety of such an arrangement to preventoverheating the neonate and also to ensurethat as much of the infants skin isilluminated as possible. Maisels7 describes asystem in which special blue lights werepositioned to within 14cm of the mattress.He adds a cautionary note: halogenphototherapy lamps cannot be positionedcloser to the infant without incurring therisk of a burn. Close attention to theoperating instructions is very important30.

In its simplest form a conventionalphototherapy device has a lamp headmounted on an adjustable, mobile stand.The lamp may then be positioned at adistance from the babys skin. Themanufacturer usually specifies a minimum

distance at which a device may be used andthis can vary from 25cm to 50cm. The,now obsolete, Vickers 80 is one of theoldest conventional phototherapy devicesseen in use today. More recent conventionaldevices include the Medela PhototherapyLamp, the Hill-Rom Micro-Lite Photo-therapy System (FIGURE 1), the DraegerPhoto-Therapy 4000 Unit (FIGURE 2), and

FIGURE 1 Draeger Air-Shields Microlite,formerly from Hill-Rom, courtesy of DraegerMedical UK.

FIGURE 2 Draeger Photo-Therapy 4000 Unit courtesy of Draeger Medical UK.

Neonatal phototherapy 11/1/05 4:33 pm Page 15

P H O T O T H E R A P Y D E V I C E S

16 V O L U M E 1 I S S U E 1 2 0 0 5 infant

the Natus neoBLUE LED PhototherapySystem (FIGURE 3). Variations on thistheme of light positioned at a distancefrom the infants skin include the MedelaBiliBed, in which a single light source ismounted in a plastic bed frame and thebaby positioned over it, and theMediprema Cradle 360. In this latter device16 fluorescent tubes are arranged aroundthe inside surface of a cylinder and theneonate is placed on a hammock in thecentre of the light field. Furtherconventional devices are now becomingavailable from Medestime in theirBilicrystal range.

Fibreoptic phototherapy

These devices use a standard light source,usually a quartz halogen bulb. The lightfrom the bulb may then be passed througha filter before being channelled down afibreoptic bundle into a pad of woven opticfibres. The pad can then be placed next tothe neonates skin. Several fibreopticdevices are available worldwide, but onlythe Ohmeda BiliBlanket (in variousversions) is available in the UK at present(FIGURE 4).

Light sourcesIn the conventional and fibreoptic

phototherapy devices a variety of lightsources may be used. These aresummarised in TABLE 1.

Fluorescent tubes are the most commontype of light source used. They are foundin two basic forms, long tubes and foldedtubes. Blue and white fluorescent tubeshave been seen in use. Typical spectra fromfluorescent tubes are shown in theEvaluation reports17,20-22.

Several phototherapy devices use thistype of light source: Vickers 80 (nowobsolete)17 uses 60cm long whitefluorescent tubes. Mediprema Cradle 360uses long blue tubes20; Draeger Photo-Therapy 4000 Unit22, Medela BiliBed22,31,and Medela Phototherapy Lamp21 usefolded blue fluorescent tubes.

Fluorescent tubes have the advantage ofbeing inexpensive but their light intensity,irradiance, reduces with time32. Users areadvised by manufacturers to change thelamps after a specified number of hours ofuse, which may range from 1,000 to 2,000hours. The MHRA15 suggest 1,500 hours.

Quartz halogen bulbs are anotherpopular choice for phototherapy device

light sources. These lamps appear whiteand have a broad light output includingstrong yellow and red components. Thismeans that the lamps tend to get quite hotand this must be borne in mind when theyare used for treatment. Various powerbulbs are used: the Datex-Ohmeda SpotPhototherapy Lamp uses one 150W quartzhalogen bulb and the Hill-Rom Micro Litethree 50W bulbs positioned in a row. TheOhmeda BiliBlanket also uses a singlehalogen bulb but the light is passedthrough a blue filter and channelled downthe fibreoptic bundle, so the heat produceddoes not reach the neonate.

Quartz halogen bulbs have not beennoted to reduce in intensity with age but

they are quite fragile,especially when hot,

and care must betaken to prolongtheir lifetime17,19.

Another form ofgas discharge bulb is used in

the Draeger Heraeus Phototherapy Lamp17

(FIGURE 5). This lamp is now obsolete, butthere are still many in use in NHShospitals. This gas discharge tube producesa broad spectrum with sharp peaks andappears a blue-white colour to the eye. Themanufacturer recommends that the lampbe changed after 1,000 hours of use.

Blue LEDs have been used in prototypephototherapy devices since the 1990s33 andin 2002 the first commercial device waslaunched in the UK and the USA. Very newto the market, this device uses an array of852 Blue LEDs, 320 yellow LEDs and 13 redLEDs23. The manufacturer states that theblue LEDs should last at least 3,000 hours.They should not decrease in intensity withage and should not be especially fragile.They should also produce less heat becausetheir spectrum is concentrated in the blueregion of the light spectrum.

Several devices use additional white andgold lights, not to improve the efficacy ofthe phototherapy, but to try to balance thecolour of the light emitted to make it morepleasant for the users to work with. Nurses

Fluorescent lamps

Quartz halogen lamps

Gas discharge tubes

Light emitting diodes (LEDs)

TABLE 1 Light sources currently in use inphototherapy devices.

FIGURE 4 BiliBlanket Plus, courtesy of GE Healthcare.

FIGURE 3 Natus neoBLUE LED, courtesy of Natus Medical Incorporated.

Neonatal phototherapy 11/1/05 1:04 pm Page 16

P H O T O T H E R A P Y D E V I C E S

V O L U M E 1 I S S U E 1 2 0 0 5 17infant

have found that working with blue lightcan cause headaches and make them feelnauseous29. Two examples of devices withwhite lights are the Draeger Photo-Therapy 4000 Unit and the NatusneoBLUE. The Draeger Photo-Therapy4000 Unit has a standard configuration offour blue folded fluorescent tubes and twowhite tubes. It may also be configuredusing six folded blue fluorescent tubes formore intensive therapy22. The two whitetubes do not contribute to the treatmentlight but can be switched on separately inorder to achieve a better colour balance forthe users. The Natus neoBLUE LEDPhototherapy System contains 320 YellowLEDs. Again, these are designed to improvethe colour balance and were incorporatedfollowing user comments that the intenseblue light caused headaches23. Interestinglythis light also includes a small section ofred lights. These are designed to be used tocentralise the lamp head over the neonate.They are activated by a toggle switch andare not on during treatment.

Safety aspects of phototherapyPhototherapy is generally considered a verysafe and well-tolerated treatment forhyperbilirubinaemia. However, clinicalusers should be aware of the unwantedeffects of using phototherapy. Thebiological hazard of blue light is almostentirely to the eye and in particular, theretina29,34. Safety precautions such as thosedescribed by Diffey and Hart29 must betaken. Usually during therapy the neonateseyes will be covered using commercial orin-house eye protection. Sometimes anamber headbox is used to block the bluelight. Retinal hazard to staff fromphototherapy devices positioned overincubators is insignificant35. The effect onother neonates close by, who are notreceiving phototherapy has not beenstudied. However, Diffey and Harts29

irradiance measurements at 50cm from anincubator illuminated by phototherapyunits, indicate a very low level of irradiance,0.2mW.cm-2. This seems to indicate thatinfants close by are at minimal risk.

The babys temperature must also becarefully monitored during treatmentbecause there may be increased heat fromthe phototherapy lamps and the neonatesmetabolic rate may increase. Insensiblewater loss is another importantconsideration especially if the neonate isalso being treated under a radiant warmer.

Unwanted ultraviolet (UV) light may be

produced by some light sources used inphototherapy. Measurement with anappropriately calibrated UV meter willdetermine whether the built in UVshielding on the device is sufficient. UVshould be reduced to very low levels orblocked completely to prevent it fromreaching the infant during phototherapy.Limits have been specified in an addendumof the international standard24.

Infrared (IR) is produced by somelamps, especially those which have a strongred and yellow component. The heatingeffect is particularly noticeable from thedevices which use halogen lamps18,19.However, all lamps will produce heat sincethey are not 100% efficient at producinglight! Many devices contain a fan to coolthe lamps22,23.

Current devices in use andcompliance with accepted criteriaIt has been said by Ennever4 and Maisels7

among others, that phototherapy devicesavailable commercially are not as effectiveas they could be. Hey36 suggests that mostconventional phototherapy is only one fifthas effective as it could be. Many devicesappear to have been designed more for theuser than for the efficient reduction ofbilirubin. To evaluate this view devicesavailable in the UK and in use in NHShospitals will be considered in the light ofthe three important criteria identified.

TABLE 2 summarises how commerciallyavailable devices meet the criteriadiscussed and also looks at the practicalconsider-ations of whether a device maybe used with an incubator if the neonateneeds environmental support. The tablealso indicates the colour of the light fromeach device, and whether any appreciableUV is produced.

Irradiance in the waveband 400nm to550nm for ten devices is shown in TABLE 2,the waveband used in the MHRAevaluations17 and specified by the IECstandard24. The irradiance values quotedare for one sample of each device readersshould be aware that there is often consid-erable variation in irradiance betweenidentical models of device. The light fromsome devices is more concentrated in theblue region as their spectra and generalcolour demonstrate and is shown in theMHRA evaluation reports17-23.

Irradiance at the manufacturersminimum recommended treatmentdistance, as measured during technicalevaluation, is shown in Table 2. As may be

seen from the table, different devices havedifferent minimum recommendedtreatment distances. The distances arefurther for halogen devices, usuallybecause these devices also have anunwanted heating effect.

The irradiance quoted for each device isthe maximum value measured at the centreof the light field. The highest irradiance atthe manufacturers minimumrecommended distance was 7.75mW.cm-2

and the lowest 0.83mW.cm-2, from the nowobsolete Vickers 80.

Often phototherapy devices arepositioned over an incubator, in which casethe device can be brought no closer thanthe incubator canopy. Incubator canopy tomattress distance has been taken as astandard 40cm. This standardisation allowsa direct comparison of device irradiance inthe 400nm to 550nm waveband for thosedevices, which may be positioned at 40cmfor treatment. TABLE 2 shows a variation inirradiance between 0.58mW.cm-2 and11.71mW.cm-2. The very high irradiancedevice, the Datex-Ohmeda Spot Photo-therapy Lamp, is recommended for use at50cm, and at 40cm may warm the neonatetoo much. The other five devices that maybe used at 40cm produce an irradiancebetween 1.86mW.cm-2 and 3.30mW.cm-2,which is acceptable since it is above theminimum criterion level of 1mW.cm-2.

Most devices are able to illuminate anarea greater than 700cm2 (one third of thesurface area of a full term neonate) at anirradiance level of 1mW.cm-2 or greater.However, light fields are rarely uniformand the irradiance will decrease towardsthe edge of the light field37,38. A highcentral field irradiance is usual. The area inwhich the irradiance is greater than1mW.cm-2 has been used as an acceptancecriterion, but it does not indicate the fieldprofile. Three devices do not achieve thiseffective field criterion of 1mW.cm-2: The Vickers 80, because of its low

irradiance The Ohmeda BiliBlanket Plus because

the pad used for treatment is only 176cm2 17

The Datex-Ohmeda Spot PhototherapyLamp because the effective light field isonly approximately 415cm2, even thoughit has a very high irradiance within thatlight field19

The UV output of the devices is gener-ally very low, but those which produce ameasurable UV level should be comparedagainst the limits specified in the standard24.

All of the devices in TABLE 2 could be

Neonatal phototherapy 11/1/05 4:41 pm Page 17

P H O T O T H E R A P Y D E V I C E S

18 V O L U M E 1 I S S U E 1 2 0 0 5 infant

physically used in the post-delivery wardover a bassinet, or with the babypositioned on or in them. Only those onstands and the fibreoptic device could beused with an infant radiant warmer orwith a baby incubator. This may or maynot be important when users areconsidering purchasing a new device.

The Ohmeda BiliBlanket and theOhmeda BiliBlanket Plus versions have ahigh irradiance but only a small effectivelight field area. However, the design allowsa greater flexibility of use; they may beused in an incubator, radiant warmer,bassinet or at home, and can be used whilethe baby is cuddled or fed.

The Medela Cradle 360 is the only devicethat can provide illumination to all of thebabys skin, but it cannot be used with anincubator and does not provide controlled

thermal support. So-called doublephototherapy, the use of two (or more)phototherapy devices to treat one neonate,significantly increases the surface areailluminated and decreases treatment time39.The actual physical size of a phototherapydevice can be very important if at least twoof them need to be positioned around anincubator. Often an Ohmeda Biliblanketand an overhead device will be usedtogether.

Factors which affect the dose and efficacyof phototherapy and recommendations forclinical application are covered in detail inthe American Academy of Pediatricsclinical practice guidelines37.

Conclusion/DiscussionMany phototherapy devices are availablecommercially and are in use in the UK

today. Phototherapy devices are generallyrobust and have few parts to go wrong. Forthis reason many currently in use are oldtechnology, but as long as the light bulbs ortubes are still available they continue to beused. Newer devices may not necessarily bemore effective than older ones but allshould meet the minimum criteria foreffectiveness. Of all the devices tested andseen, only the Vickers 80 fails to providesufficient irradiance.

For a baby requiring an incubator theMedela Phototherapy Lamp, the DraegerPhoto-Therapy 4000 Unit, the DraegerHeraeus Phototherapy Lamp and theNatus neoBLUE LED Phototherapy Systemall meet the above criteria (irradiance,waveband and effective surface area).

For babies not needing thermal support,the Medela BiliBed and the MedipremaCradle 360 also meet the criteria. The

Device

Draeger Photo- Blue & white Folded fluorescent 30cm 3.39 (4 blue 2.16 (4 blue Yes 0.009 YesTherapy 4000 options tubes(6) tubes and 2 2 white)Unit white tubes) 2.64 (6 blue)

4.07 (6 blue tubes)

Draeger Heraeus White Gas discharge 30cm 5.03 3.30 Yes 0.12 YesPhototherapy bulb (1)Lamp

Medela Blue Folded fluorescent 25cm 4.66 2.08 Yes 0.016 YesPhototherapy tubes (4)Lamp

Medela BiliBed Blue Folded fluorescent On frame 5.56 Not applicable Yes 0.000 Notube (1) (~6cm)

Ohmeda Blue Halogen bulb (1) In contact 4.83 Not applicable No 0.025 YesBiliBlanket Plus

Datex-Ohmeda White Halogen bulb (1) 50cm 7.75* 11.71* No 0.120 YesSpot Phototherapy Lamp

Hill-Rom Micro- White Halogen bulbs (3) 42cm 2.50 As for manufac- Yes 0.002 YesLite Phototherapy turers recom-System mended distance

Natus neoBLUE LED Blue LEDs 30cm 2.29 1.86 Yes 0.000 YesPhototherapy (yellow & red) 852 BlueSystem 320 Yellow

13 Red

Mediprema Blue Long fluorescent On gauze 5.25 Not applicable Yes 0.005 NoCradle 360 tubes (16) hammock ~20cm

Vickers 80 White Long fluorescent None specified 0.83 @ 30cm 0.58 No 0.04 Yestubes (4)

* Manufacturer states irradiance at 50.8cm (but this was not explicit in the manual and was not known prior to measurement)Note: 40cm is a standard distance used to approximate the distance of the lamp head from the mattress when the phototherapy device is used over an incubator.There are several models of incubator in use in the UK, all with different canopy heights. None of the manufacturers recommend using their device at 40cm.

Can

th

e de

vice

be

use

dw

ith

a b

aby

incu

bato

r?

UVA

320

nm

to

400n

m a

tth

e m

anu

fact

ure

rsm

inim

um

reco

mm

ende

ddi

stan

ce (m

W.c

m-2)

Is t

he

effe

ctiv

e lig

htfi

eld

>700

cm2 ?

Irra

dian

ce a

t st

anda

rd40

cm d

ista

nce

(app

roxi

mat

ein

cuba

tor

can

opy

tom

attr

ess

dist

ance

)(m

W.c

m-2)

Irra

dian

ce a

tm

anu

fact

ure

rsm

inim

um

reco

mm

ende

dtr

eatm

ent

dist

ance

(mW

.cm

-2)

Man

ufac

ture

rsm

inim

um re

com

men

ded

dist

ance

bet

wee

n th

ela

mp

head

and

the

neon

ate

(cm

)

Lam

p ty

pe

Colo

ur

of li

ght

TABLE 2 Phototherapy device data.

Neonatal phototherapy 11/1/05 1:05 pm Page 18

Datex-Ohmeda Spot Phototherapy Lampprovides a very high irradiance but onlyover a small area19,31 and the Hill-RomMicro-Lite Phototherapy System providesa medium irradiance but over a limitedarea. Ohmeda BiliBlankets have a highirradiance but small effective treatmentarea, but this disadvantage is offset by theversatility of the device.

We can conclude that not allphototherapy devices are equally effective.When their characteristics are compared tothe three important criteria identifiedmore informed decisions can be madeabout the device chosen to administerphototherapy. Care must be taken inchoosing a device which will be effectiveand also be easy to use and acceptable tothe clinical users and parents.

Acknowledgements

I would like to thank the MHRA forfunding much of the phototherapy workand Dr Diane Crawford and the team inCEDAR. DH evaluation reports can bedownloaded by NHS staff fromwww.medical-devices.gov.uk or ordereddirectly from MHRA on 020 7972 8181. Iwould also like to thank Dr Colin Gibson,Dr John Mecklenburgh, Mr David Taylorand Dr Maurice Wentworth for theirsupport and helpful discussions.

References1. Blackburn S. Hyperbilirubinaemia and neonatal

jaundice. Neonatal Network 1995; 14(7): 15-25.

2. Valman H. B. The first year of life. In: Jaundice in the

newborn. 4th edition BMJ Publishing Group. 1995.

3. Cremer R. J., Perryman P. W., Richards D. H. Influence

of light on the hyperbilirubinaemia of infants.

Lancet 1958; 1094-97.

4. Ennever J. F. Blue light, green light, white light, more

light. Treatment of neonatal jaundice. Clin Perinat

1990; 17: 467-81.

5. Ennever J. F. Phototherapy for neonatal jaundice. In:

Polin RA and Fox WW, eds. Fetal and Neonatal

Physiology 1992; 112: 1165-73. Philadelphia: W B

Saunders.

6. Maisels M. J. Neonatology - Pathophysiology and

Management of the Newborn. Avery G B, Fletcher M

A, MacDonald M H, eds. 1994: 38.

7. Maisels M. J. Why use homeopathic doses of

phototherapy? Pediatrics 1996; 98: 283-87.

8. Metherall J. Phototherapy for neonatal

hyperbilirubinaemia: Delivering an adequate dose.

JNN 2003; 9(6): 183-86.

9. Ives N. K. Neonatal jaundice. In: Rennie, J. and

Robertson, N., eds. Textbook of Neonatology 3rd

edition. Edinburgh: Churchill Livingstone. 1999.

10. Tan K. L. Efficacy of fluorescent daylight, blue and

green lamps in the management of nonhemolytic

hyperbilirubinaemia. J Pediatrics 1989; 114: 132-37.

11. Tan K. L., Lim G. C., Boey K. W. Efficacy of high

intensity blue light and standard daylight

phototherapy for non-haemolytic

hyperbilirubinaemia. Acta Paediatr 1992; 81: 870-74.

12. Pratesi R. Agati G., Fusi F. Phototherapy for neonatal

hyperbilirubinaemia. Photodermatology 1989; 66:

244-57.

13. Donzelli G. P., Pratesi S., Rapisardi G., Agati G., Fusi

F., Pratesi R. 1 day phototherapy of neonatal

jaundice with blue-green lamp. Lancet 1995; 346:

184-85.

14. Tan K. L. The nature of the dose response

relationship of phototherapy for neonatal

hyperbilirubinaemia. J Pediatrics 1977; 90: 448.

15. DH. The application of phototherapy. Health Equip-

ment Information (HEI) No. 202 September 1992.

16. Health Devices. Fibreoptic phototherapy systems.

Health Devices 1994; 24: 132-53.

17. DH. Neonatal phototherapy. A review including

evaluations of Ohmeda BiliBlanket Plus and Medela

BiliBed. Evaluation 391. London: Medical Devices

Agency (MDA). 2000.

18. DH. Neonatal Phototherapy: Hill-Rom Micro-Lite

Phototherapy System. Evaluation 00091. London:

MDA. 2001a.

19. DH. Neonatal Phototherapy: Datex-Ohmeda Spot

Phototherapy Lamp. Evaluation 00092. London:

MDA. 2001b.

20. DH. Neonatal phototherapy: Mediprema Cradle

360. Evaluation 01160. London: MDA. 2001c.

21. DH. Neonatal phototherapy: Medela Phototherapy

Lamp. Evaluation 01161. London: MDA. 2001d.

22. DH. Neonatal phototherapy: Draeger Photo-Therapy

4000 Unit. Evaluation 01162. London: MDA. 2001e.

23. DH. Neonatal phototherapy: Natus neoBLUE LED

Phototherapy System. Evaluation 04143. London:

Medicines and Healthcare products Regulatory

Agency (MHRA). 2004.

24. International Electrotechnical Commission (IEC).

Medical Electrical equipment part 2-50: Particular

requirements for the safety of infant phototherapy

equipment. 2003.

25. Dicken P., Grant L. J., Jones S. An evaluation of the

characteristics and performance of neonatal

phototherapy equipment. Physiological

Measurements 2000; 21: 493-503.

26. Modi N., Keay A. J. Phototherapy for neonatal hyper-

bilirubinaemia. Arch Dis Child 1983; 58: 406-09.

27. International Commission on Radiological

Protection (ICRP). Report of the task group on

reference man. ICRP publication 23. 1975.

28. Tan K. L. Comparison of the efficacy of fiberoptic

and conventional phototherapy for neonatal

hyperbilirubinaemia. J Pediatrics 1994; 125: 607-12.

29. Diffey B., Hart G. Ultraviolet and blue-light

phototherapy principles, sources, dosimetry and

safety. IPEM Report 76, York. 1997.

30. DH. Phototherapy devices for the treatment of

neonates and infants. Hazard warning HN9606

1996. www.medical-devices.gov.uk (last accessed

13.12.04).

31. Wentworth S. D. P. A study of neonatal

phototherapy devices. Proceedings of the Sixth

Annual Scientific Conference of the Institute of

Physics and Engineering in Medicine. York, IPEM.

2000. www.medphys.soton.ac.uk/IPEM2000 (last

accessed 14.12.04).

32. Tan K. L. Phototherapy for neonatal jaundice. Clin

Perinat 1991; 18: 423-39.

33. Vreman H. J., Wong R. J., Stevenson D.K. et al. Light-

emitting diodes: A novel light source for photo-

therapy. Pediatric Research 1998; 44(5): 804-09.

34. Abramov I, Hainline L, Lemerise E, Brown A.

Changes in visual functions of children exposed as

infants to prolonged illumination. J Am Optometric

Assoc 1985; 56: 614-19.

35. Hart G., Day C., Hainsworth A. Phototherapy for

neonates. JNN 1997; 3(4): centre insert.

36. Hey E.N. Phototherapy: Fresh light on a murky

subject. MIDIRS Midwifery Digest 1995; 5(3): 256-260.

37. American Academy of Pediatrics. Clinical practice

guidelines subcommittee on hyperbilirubinaemia.

Management of hyperbilirubinaemia in the

newborn infant. Pediatrics 2004; 114(1): 297-316.

38. Wentworth S. D. P. Neonatal phototherapy: Which

device is best for your babies? A review of nine

devices. Poster presentation at IPEM scientific

meeting Output and safety of optical devices

October 2002. Poster and oral presentation at the

Annual National Neonatal Nurses Conference,

Nottingham, September 2002.

39. Newman T. B., Maisels M. J. Evaluation and treat-

ment of jaundice in the term newborn: A kinder,

gentler approach. Pediatrics 1992; 89(5): 809-18.

P H O T O T H E R A P Y D E V I C E S

V O L U M E 1 I S S U E 1 2 0 0 5 19infant

FIGURE 5 Draeger Heraeus phototherapy lamp.

Neonatal phototherapy 11/1/05 4:35 pm Page 19