neonatal phototherapy - cedar · neonatal phototherapy device. light from a halogen bulb is...

Neonatal Phototherapy

A reviewincluding evaluations of

OhmedaBiliBlanket®Plus

NUMBER

391

MedelaBiliBed™

Neonatal Phototherapy

MDA Evaluation 391, April 2000 2

INTRODUCTION

This issue of Evaluation is our first examination ofphototherapy equipment for the treatment ofneonatal jaundice (hyperbilirubinaemia). A surveyin the Appendix 1 & 2 covers both equipmentcurrently available in the UK and equipment nolonger available but in use in the NHS.

Phototherapy Equipment AvailablePhototherapy equipment can be divided into twomain categories. The first type consists of a lightunit which may be positioned above or below thebaby. These units may include blue or whitelamps. This type of phototherapy has been on themarket for some 40 years and is usually referred toas conventional phototherapy.

A newer development is the fibreoptic form ofphototherapy equipment. This type delivers lightfrom a halogen bulb via a fibreoptic cable to a padcontaining woven optical fibres. The pad is placednext to the baby's skin. This newer type has beenon the market for around 10 years.

Devices coveredThis issue includes evaluations of two devicescurrently available in the U.K. Comparativetechnical data is given in Appendix 2 for threeother devices currently used in the NHS. Furtherevaluations will be published in later issues.

You are encouraged to contact our evaluationcentre, CEDAR (see Appendix 3) in Cardiff forfurther information on our evaluations. For detailsof configurations, prices and other factors youshould contact the manufacturers or suppliers.

Issues to Consider in PurchaseA phototherapy unit should be selected afterconsideration of the following important but by nomeans exhaustive criteria: the ability to meetclinical need, technical performance, ease of use,compliance with European Directives, compliancewith Standards, likely reliability, ease of servicing,and price.

Meeting Clinical Need This is discussed in theAppendix 1 - Current Thinking on Phototherapy.

Likely Reliability and Running CostsPhototherapy units tend to be of a fairly simpleconstruction with little to go wrong. The maincosts will lie in the purchase of consumables. Allunits will need replacement lamps and some mayneed replacement filters. In devices usingfluorescent lamps, light output decreases withtime; the lamps, therefore, need to be replacedafter some 1000 to 1500 hours in use, as per themanufacturers instructions. Devices using halogenlamps have a more steady output and they need tobe replaced only when they fail.

Those devices which may come into contact withthe patient may require disposable or washablecovers. As with all medical devices regularservicing and safety checks are essential to ensureefficient operation of the device and safety for thepatients and staff.

SPECIAL NOTE: Warranties and ServicingIn common with many medical devices,phototherapy equipment requires routine servicing.The service period is typically 3 or 6 months.Although new equipment normally has a one-yearwarranty against breakdown, servicing is stillrequired within the warranty period (e.g. to checkoutput from the lights).

Any purchasing decision should include serviceprovision from the date of purchase, not from thedate of expiry of the warranty.

CONTENTS Page

Introduction 2Summaries Ohmeda BiliBlanket Plus 3 Medela BiliBed 4User assessment 5Technical evaluation 9Manufacturers' comments 11Appendices

1. Current thinking on phototherapy 122. Review of some devices in use 153. Acknowledgements and 16

general appendices 16

Summaries

MDA Evaluation 391, April 20003

OHMEDA BILIBLANKET PLUS

SUMMARY

Advantages: Negligible heat production attherapy pad, no eye pads necessary when usedon its own, infant may be nursed duringtherapy, can be used in special care baby unitsand in the community.

Disadvantages: Pad only available in a smallsize*, considered a little inflexible and hard bysome users, bulbs do not last as long asexpected.

Overall: Modern fibreoptic phototherapysystem suitable for high intensity therapy forpre-term babies and less intensive therapy forlarger full-term babies. Well received by parentsand nursing staff.

BRIEF DESCRIPTIONThe Ohmeda BiliBlanket Plus is a fibreopticneonatal phototherapy device. Light from ahalogen bulb is filtered and channelled into a flatpad of woven optic fibres via a fibreoptic cable.The filter in the main unit removes most of theultraviolet and infrared components of the light andthe light appears blue-green to the user. It has aneffective bandwidth of 400 to 550nm, peakingaround 530nm wavelength.

The fibreoptic pad is placed against the infant'sskin and they may be fed, changed and cuddledwithout interfering with therapy. The intensity ofthe light can be varied. The unit is designed tomake infant eye protection unnecessary whenused as a single therapy. An LCD meter on thefront of the main box shows the number of hoursthe device has been in use.

MAIN FEATURES

• Fibre optic pad• Variable intensity• One halogen bulb• Wide waveband 400nm to 550nm• Meter to show total hours in use

OptionsThe BiliBlanket Plus is available as• Phototherapy only• Phototherapy and Transilluminator ready• Phototherapy and Transilluminator

Replacement Items• Bulb (box of 6) £144• Pad £565• Disposable pad covers (50) £ 26• Disposable vests (50) £ 50

Life span of lamp - Manufacturer states lamp lifeof 700 hours when used continuously at 25 °C onthe high intensity setting. Lamp to be changedwhen it fails.

SERVICINGNo training courses are available for technicalstaff.There is a combined operating and service manualavailable.

Price ex VAT £2,000 includes1 transilluminator5 disposable vests10 disposable covers1 spare bulb

Manufacturer Ohmeda Medical 9065Guilford Road, Columbia MD21046 USA

Supplier: Datex-Ohmeda Ltd71 Great North RoadHatfieldHertfordshireAL9 5ENTel01707 263570Fax:01707 260065web page:

www.datex-ohmeda.com

CE Marking MD Directive, Annex IINotified Body BSI (ID 0086)

How is safetydemonstrated?

Independent certification toIEC 601-1:1988/IEC 60601-1: 1990EN 60601-1-2:1993

* See Manufacturer's Comments

Summaries


MEDELA BILIBED

SUMMARYAdvantages: Low heat production at therapysite, no infant eye protection necessary whenused on its own. Therapy can be carried outbeside mother to avoid separation. Can be usedin hospital units or the community.

Disadvantages: Not for use in incubators.

Overall: Modern easy to use phototherapy unit.Small patient-to-light distance enables highintensity therapy. Well received by parents andnursing staff.

Supplier:Tel: 01538 399541Fax: 01538 399572

web page: www.centralmedical.co.uk

BRIEF DESCRIPTIONThe Medela BiliBed is a fluorescent lamp typeneonatal phototherapy device for neonates notneeding an incubator. The unit fits into a crib orbassinet and a stretched plastic cover provides asoft surface over the light for the infant. Aspecially designed "baby suit", called aBilicombi, attaches to the plastic cover withVelcro, this keeps the child in position and isdesigned to reduce unwanted light and glare tocarers and parents. The unit is designed to makeinfant eye protection unnecessary when used asa single therapy. Two LCD meters indicate thenumber of hours the device has been in use andthe number of hours of patient treatment; thesecond meter can be reset between patients.

MAIN FEATURES

• Lightweight bed unit• One blue-light fluorescent tube• Wide waveband 400nm to 550nm• Meter to show length of therapy (hours)• Meter to show total hours in use• Hand switch

Options include:• Washable "baby suit"• Disposable "baby suit"

Replacement Items• Blue-light fluorescent tube £18• Washable "baby suit" £38• Disposable "baby suit" £15• Plastic cover £38• Frame for plastic cover £125

Life span of lamp - Manufacturer recommendslamp change after 1,500 hours of use

SERVICINGServicing Training CoursesTraining courses are available for technical staff ifrequired.The Service Manual is provided free of charge.

Typical Servicing CostsUnits may be returned to Central Medical SuppliesLtd for annual servicing and repairs.

Minor repair £95Major repair £120Annual service and safety check £70Carriage £10

Price ex VAT £1,695 Includes two washable "baby suits"

Manufacturer Medela AG Medicaltechnology, Lattichstrasse 4,6341 Baar/Switzerland

Central Medical Supplies LtdCMS House, Basford Lane,Leekbrook, Leek, Staffs.ST13 7DT

CE Marking MD Directive, Annex IINotified Body TUV (ID 0123)

How is safetydemonstrated?

Independent certification toIEC 601-1:1988/EN 60601-1:1990 (Nemko)

User Assessment


USER ASSESSMENT

We assessed two user groups independently, onefor each device. The groups comprised nurses andmidwives, both new and existing users. Therespondents completed a questionnaire whichasked them to score the facilities and attributes ona scale from 0 to 10, where 0 was unacceptableand 10 was excellent.

We subsequently conducted a structured interviewwith most respondents in which they explained thereasons for their scores. We have included theircomments and conclusions in the report. Noattempt has been made to prioritise facilities.

Ohmeda BiliBlanket PlusEleven new users and ten existing userscommented on the Ohmeda BiliBlanket Plus, anda further ten existing users commented on theprevious version of the device called the OhmedaBiliBlanket. This group was drawn from sixhospitals. From the users' perspective the OhmedaBiliBlanket is essentially the same as the OhmedaBiliBlanket Plus. The newer version has an hoursmeter, a transilluminator and a few technicalchanges. The reactions of the users to the OhmedaBiliBlanket Plus are shown in Figure 1.

Users considered the Ohmeda BiliBlanket Plus aneffective phototherapy device. They found it easyto set up and use, but some users considered theunit noisy. Bulbs were changed by the MedicalPhysics/Clinical Engineering departments. Thedevice was used for continuous treatment andmedical procedures were performed duringphototherapy. The nursing staff thought this wasadvantageous. In post delivery units theBiliBlanket Plus was used to treat babies besidetheir mothers. This was liked by both the staff andparents. Keeping the mother and baby togetherreduces parental anxiety and promotes the bondingprocess.

Clinical users found this device relatively easy touse with other neonatal devices. It was used inincubators in the neonatal departments. The cablewas passed through a tubing port at the foot end ofthe incubator. Our users preferred to use it withnewer incubators which had larger and morenumerous tubing ports. In some post-natal andneonatal departments it was used in conjunctionwith overhead phototherapy devices to providehigher dose double phototherapy.

Main light box: Users considered the main lightbox easy to set up and use. Our users commentedthat the controls and the attachment of the fibre-optic cable was easy.

Photo 1: Ohmeda BiliBlanket Plus Light Box

Several users would have preferred a less heavydevice, particularly those in units where patientdevices were placed on shelves around the patient.Some users would have preferred a smaller box asthe space around the patient, especially in aneonatal unit, is at a premium. They found it easyto position either on the canopy of the incubator oron a small trolley. Users commented that it tookup less room than a conventional overhead unit.

BiliBlanket pad: The light cable was easy toattach to the main light box. However, some userswould have preferred a longer cable; they wouldalso have liked it to have been more flexible. Thiswas especially the case where the OhmedaBiliBlanket Plus was used to treat a baby in anincubator.

Photo 2: BiliBlanket Plus Fibreoptic Pad

User Assessment


The size of the light pad was considered to beacceptable for small babies. A larger pad wouldhave been preferred for larger babies. Some userswould have liked adjustable or interchangeablepads to suit the size of the baby.

Our users did not think that the pad wasparticularly comfortable for the baby to lie on norwas it considered flexible enough. Some userswould have preferred to have been able to wrap itaround the baby.

The light glare from the pad was not considered tobe a problem and no member of staff reported anyheadache or nausea problems while working withthe Ohmeda BiliBlanket Plus. Eye protection wasnot needed for the neonate as the light ispositioned behind the baby's head. This wasconsidered an advantage by both staff and parents.CEDAR Note: When used with overheadphototherapy units for double phototherapy, eyeprotection was necessary.

Photo 3: Ohmeda BiliBlanket Plus fibreopticpad with cover.

The Ohmeda BiliBlanket Plus pad was consideredeasy to clean. The pad may be used directlyagainst the neonate's skin or may be covered usingeither a disposable pad cover or a disposable"vest". The pad covers slide over the pad andattach to the light cable with sticky tabs, as shownin Photo 3, and they were well liked by our users.

The "vests" also slide over the pad and attach tothe light cable but they have an additional strapsection for securing around the baby's mid-section.The "vests" available to existing users were liked;but users found that if they were not correctlypositioned they could chafe the baby's axillae.These users would have liked the "vests" to havesofter edges. The "vests" were not seen during theevaluation.

The pad covers and "vests" are specificallydesigned to be used with the BiliBlanket pad andto allow as much of the therapeutic light throughas possible. CEDAR note: Using cotton sheets orabsorbent paper towels instead of a pad cover or"vest" reduces the light output from the pad,decreasing the effectiveness of the treatment.

Photo 4: Ohmeda Biliblanket Plus with trans-illuminator accessory attached

Transilluminator: Users found this easy to useand the light cable was sufficiently long. One usercommented that the light output was not as brightas from a dedicated transilluminator unit in theneonatal department. However, its light output wasconsidered sufficient.

Overview: The reaction of the users to theOhmeda BiliBlanket Plus was generallysatisfactory. There were no large discrepanciesbetween the reactions of the new and existingusers.

Medela BilibedFive new users and nine existing users, drawnfrom five hospitals, commented on the MedelaBiliBed. Their reactions are shown in Figure 2.

Existing users considered the BiliBed an effectivephototherapy device. It was in use in special carebaby units and in post-natal wards. All users usedthe device in continuous therapy. They found iteasy to set up and use.

Medical Physics/Clinical Engineering departmentsattached the plastic film to the frame for mostusers' departments. Those users who had set up theframe themselves found it fiddly. Bulbs werechanged by Medical Physics/Clinical Engineeringdepartments.

Nursing and midwifery staff particularly noted thatthe baby settled well on the BiliBed and that there

User Assessment


Figure 1: Ohmeda BiliBlanket Plus User Responses

Figure 2: Medela BiliBed User Responses

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User Assessment


was less parental anxiety for the baby when aMedela BiliBed, as opposed to an overheaddevice, was used for phototherapy. The motherswere also more content when their babies werebeing treated beside them. In some units the usualmethod of treatment with phototherapy requiredthe baby to be placed in an incubator and anoverhead phototherapy unit used; the incubatorbeing required to keep the baby warm. The userscommented that this had a negative psychologicaleffect on the mothers who then saw their babies asbeing seriously ill even though their condition wasconsidered mild by the clinical staff.

Photo 5: The Medela BiliBed with "baby suit" intreatment position, handswitch illustrated.

Baby Suit : The baby is positioned over the lampin a disposable or towelling, washable "baby suit".Many users found the washable suits easy to use.Existing users found that the gauze/muslin panelwore thin after approximately a year in use, andwas then considered uncomfortable for the babiesto lie on. Larger babies tended to become sweatyas they were more in contact with the plastic filmover the lighting unit. None of the existing usersused the disposable "baby suit"; new users dislikedthe material. Some users thought that the suitswere too large for the very small babies, and foundthat they could be restrictive around the baby'sneck if the cot was tilted.

It is important that as much of the baby's skin isexposed to the light as possible. If the babies beingtreated were small then particularly small nappieshad to be used so that the area of the baby's skinexposed to the light was maximised. Normal sizednappies were considered too large because theycovered too much of the baby's back to alloweffective therapy.

The light glare from the unit was consideredacceptable by the nursing and midwifery staff. Nomember of staff reported any headache or nauseaproblems whilst working with the Medela Bilibed.

Clinical staff found the bed and the "baby suits"easy to clean. One user noted that the "baby suits"took a long time to dry.

The Medela BiliBed was used in some units inconjunction with an overhead unit to providehigher dose double phototherapy and the usersfound this satisfactory. During doublephototherapy eye protection was provided for theneonate.

Photo 6: Washable "baby suit" for MedelaBiliBed

All of our users liked using the Medela BiliBed.Two existing users in different hospitalscommented that although they had overheadphototherapy devices available in their unit theypreferred to use the Medela BiliBed. Several userscommented that they would like to see morepublished clinical research using the BiliBed toconfirm their convictions.

Overview : The general reaction of the users to theMedela BiliBed was good. The largest discrepancyof opinion between new and existing users wasover the issue of effectiveness in reducingbilirubin levels.

Technical Evaluation


TECHNICAL EVALUATIONThere is currently no specific standard forphototherapy devices so we tested thoseperformance characteristics of the devices weconsidered important to clinical effectiveness andsafety. Measurements were made of the lightoutput for therapy using a Bentham doublemonochromator spectroradiometer. This was usedto measure the light intensity at each wavelengthwithin a pre-set waveband. The temperature rise atthe treatment site while the device warmed up andover a period of several hours was also measured.Phototherapy units are not designed to warmbabies. These performance tests were carried outon "unloaded" devices, that is, not during apatient's treatment.

Ohmeda BiliBlanket PlusThe Ohmeda BiliBlanket Plus phototherapy deviceconsists of a main unit containing a halogen bulband a fibreoptic pad for delivering the light to thebaby. The light from the bulb is filtered in themain unit and the therapeutic light passed downfibre optic cables. These cables are then woveninto a pad, which is encased in a protective plasticcover. The filter in the main unit removes most ofthe infrared (IR) and ultraviolet (UV) componentsof the light. A fan cools the components in themain unit.

The temperature of the BiliBlanket pad wasmeasured during the warm up of the bulb and inoperation. The temperature was found to be nomore than 2°C above room temperature after beingrun for three hours. This is an acceptable resultsince the pad is not intended to warm up. Filters inthe main box are designed to remove the warminginfra-red component of the light from the bulb andprevent it from reaching the pad.

The light output was measured between 320nm to600nm, a waveband chosen to include all possibletherapeutic wavelengths (see Appendix). Theoutput spectrum shown in Figure 3 is as expectedfrom a halogen light source. An Ohmedaprotective cover was then placed over the pad andthe irradiance remeasured. This irradiance plot isalso shown in Figure 3 and shows negligiblereduction.

The light intensity output from the BiliBlanket padis sufficient to reduce the bilirubin level in infants,but it is not considered to be the most effectivedevice because of its size (see Appendix). Theirradiance is only slightly reduced by the covers.However, it is important that only the covers (or

"vests") are used to protect the pad; other materialssuch as paper towels or cotton sheets if placedbetween the infant and the light will attenuate thelight to an unknown degree and will probablyreduce the effectiveness of the therapy. Ohmedastate that only Ohmeda disposable vests andcovers should be used to protect the BiliBlanketPlus pad as "use of other materials may reducetherapeutic light output".

Manuals The user manuals were supplied free ofcharge with the device. They contained clearphotographs and explanations. The service manualis chargeable.

Servicing The Ohmeda BiliBlanket Plus wasthought by technical staff in a sample of NHSTrusts, to be easy to service. The manufacturerstates that the bulbs should be changed when theyfail. The bulbs were changed when they failed andthis occurred more often than expected.

Medela BiliBedThe Medela BiliBed phototherapy device consistsof a rectangular unit which fits neatly into hospitalbassinets or cots. The unit contains one compactfluorescent lamp. The lamp is recessed within thebed and covered by a transparent perspex sheetwith a diagram of a baby on it. A frame with aplastic stretch film on it is then placed over theperspex and a special "baby suit" attached to theframe using Velcro. Both the diagram of the babyand the "baby suit" are designed to aid the clinicalstaff position the baby correctly for treatment.

The temperature rise on the perspex cover and theflexible bed cover were measured while the devicewarmed up. The temperature increased by no morethan 6°C above ambient temperature after threehours of operation. The Medela BiliBed is notdesigned to keep the infant warm and neithershould it increase the infant's temperature.

The light output was measured and is shown inFigure 4. The output spectrum is as expected for acompact fluorescent bulb. The "baby suit"designed to hold the infant in place over the lightsource was then attached and the irradianceremeasured. This is the second spectrum shown.With the "baby suit" in place there is noappreciable attenuation of the irradiance by thegauze. The two spectra are so similar they aredifficult to distinguish on the figure.



Figure 3: Ohmeda BiliBlanket Plus Spectra with and without Protective Cover

Figure 4: Medela BiliBed Spectra with and without "Baby Suit" Gauze

Figure 5: Spectral Irradiance Comparison

0.00

0.02

0.04

0.06

0.08

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320 340 360 380 400 420 440 460 480 500 520 540 560 580 600

Wavelength (nm)

Irra

dia

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(m

W.c

m-2

.nm

-1)

Without gauzeWith gauze

Irradiance from 400nm to 550nmwithout gauze 5.56 mW.cm-2

with gauze 5.54 mW.cm-2

Curves are very nearly coincident

0.00

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Wavelength (nm)

Irra

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-1)

Without coverWith cover

Irradiance from 400nm to 550nmwithout cover 4.83 mW.cm-2

with cover 4.52 mW.cm-2

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Medela BiliBed

Ohmeda BiliBlanket Plus



Manuals User manuals and service manuals weresupplied free of charge. They are clear andconcise.

Servicing The Medela BiliBed was thought easyto service by technical staff in the two NHS Trustswhich we sampled. The manufacturer states thatthe lamp should be changed after 1,500 hours ofuse. Occasional replacement of perspex covers,plastic film and frames will be required and theseare available from the supplier.

SPECTRAL COMPARISON

The two devices were compared technically on thebasis of their irradiance, spectral plots, seeFigure 5, and effective light areas.

Table 1

BiliBlanket BiliBed

320nm to400nm (UV)

0.0248 0.0004

Irra

dian

cem

W.c

m-2

400nm to550nm

4.83 5.56

Approximate effectiveSurface area (cm2)

176 704

The UV component of the radiation emitted byeach device shown in Table 1 can be consideredinsignificant. They are below published safetylimits.

The irradiance from each device in the wavebandof interest, 400nm to 550nm, is similar. Theeffective surface area is the treatment areaavailable from the light source. For the OhmedaBiliBlanket Plus the effective surface area is thearea of the pad, for the Medela BiliBed it is thearea of the gauze panel.

The Medela BiliBed has the larger effectivesurface area although it must be appreciated thatnot all of the light in this area will reach the baby.The geometry becomes more complicated than aflat plane because the "baby suit" is attached to aplastic surface, which gives under the baby'sweight to provide a comfortable surface to lie on.The whole of the Ohmeda BiliBlanket surface areashould be in contact with the baby.

The shape of the spectra from the two devices arevery different, the Medela BiliBed lamp producesa peak at around 430 to 450nm, which is in theusually accepted range for treatinghyperbilirubinaemia. The Ohmeda BiliBlanketPlus spectrum peaks in the green area of thevisible spectrum. There is currently debate over

whether this is more effective therapeutically (seeAppendix). The gently rising slope is as expectedfrom the halogen bulb light source.

Both devices may be used for double phototherapywhen used in conjunction with an overheadphototherapy device.

MANUFACTURERS' COMMENTS

Datex-Ohmeda: Thank you for your kindinvitation to comment on the draft of the report.We would like to make the following points.

1. New pad sizes are currently being evaluated,and are restricted because of loss of efficiencydue to output versus area.

2. The BiliBlanket Plus is designed so thatchanging the bulb should be easy and possiblewithout special tools or technical help, makingit especially useful in busy units and in thecommunity.

3. Wrapping a fibre optic bundle pad around ababy would probably restrict the efficiency ofthe treatment as the pad may not exactly fit thebaby. Fixing it around the baby would beimpractical and treatment may need to beinterrupted to carry out routine checks. Theaction of wrapping and unwrapping may alsoincrease the potential for damage to the lightbundles. CEDAR Note: At least onephototherapy device using a wraparound padexists but it is not available in this country.

Medela/Central Medical Supplies: Thank you forthe opportunity to review the draft of the report.Medela AG were very satisfied with yourconclusions.

APPENDIX 1


This section is a summary of a full literature review currently being submitted for publication in a peerreviewed journal, and the full text and reference sources are available on request, from CEDAR. Therecommendations given here are based on papers published in clinical or scientific journals, however, thissummary should not be viewed as exhaustive or definitive.

A SUMMARY OF CURRENT THINKING ON NEONATAL PHOTOTHERAPY.

Neonatal hyperbilirubinaemia is an excess ofbilirubin in the blood and it causes the baby tolook jaundiced. Phototherapy takes advantage ofthe effect that certain wavelengths of light have onthe bilirubin molecule.

The production of bilirubin is a normal process; itis a breakdown product of haemoglobin. Normallybilirubin is conjugated by the liver and excreted inbile. Before birth, foetal bilirubin is removed bythe placenta and is excreted by the mother.Immediately after birth the biochemical processfor removal of bilirubin by the neonate's liver mustbe "switched on". The baby is then able to excretebilirubin itself. In some babies the liver is unableto conjugate sufficient bilirubin because ofimmaturity and the blood serum bilirubin levelrises. By circulating in the blood the bilirubinreaches almost all organs in the body, includingthe skin, causing the characteristic yellow jaundicecolour. It is important to monitor levels ofbilirubin in jaundiced neonates because, if theblood plasma concentration exceeds a certainlevel, there is a danger of bilirubin causing braindamage.

Before the 1940s bilirubin encephalopathy was aleading cause of neonatal death and cerebral palsy.Since then exchange transfusions, reduction inrhesus haemolytic disease and better cross-matching of blood transfusions have greatlyreduced the incidence of mortality and braindamage from hyperbilirubinaemia. In 1958 anursing sister noticed that the yellow colouring ofa baby's skin faded following exposure to sunlight.This led to the development of phototherapy. Bystudying the effect of light on bilirubin in thelaboratory an "action spectrum" of light onbilirubin in vitro was derived. The "actionspectrum" peaks at 450nm. Light containing thiswavelength should be the most effective.

The efficiency of phototherapy to reduce bilirubinlevels is directly related to three factors: theintensity and waveband of the light used and thesurface area of skin illuminated.

IntensityResearch has shown that given that the light is inthe effective waveband, the decline in the bilirubin

level is proportional to the irradiance of the light.

Guidelines published by DoH in 1992 stated thatthe irradiance should be no lower than0.45mW.cm-2 for mild hyperbilirubinaemia and itshould be higher than 1mW.cm-2 for more seriouscases. The irradiance can be increased by eitherusing a more intense light source, or by bringingthe light source closer to the patient. Care must betaken when reducing the distance between the lightsource and the patient as certain light sourcesproduce appreciable levels of infrared radiationthat can burn patients. Hazard Notice HN9606covering this problem was issued by the MDA andis summarised in Box A1.

It is also important that the intensity and thewaveband in which the intensity is measured areclearly stated so that direct comparisons betweendevices can be made. If irradiance is stated ineither µW.cm-2, (as used by the AmericanAcademy of Pediatrics) or mW.cm-2 for an agreedwaveband, devices can be compared.

Colour: Waveband of LightBilirubin only absorbs light within a givenwaveband. The "action spectrum" was derivedfrom in vitro tests on bilirubin and peaks around450 nm, which is in the blue region of the visiblespectrum.

Box A1-HAZARD MDA HN 9606-A SUMMARYPhototherapy - Potential burns to patients.Problem: The MDA has received reports ofphototherapy devices not being used accordingto the manufacturers' instructions, resulting inburns to patients.Action: Managers and staff are advised toensure that the manufacturers' instructions forthe use of phototherapy devices are availableand followed. In particular ensure that;• The lamp is at the correct height above the

patient.• Filters required for safe operation are in

place.• The correct type of replacement lamps are

used as recommended by the manufacturer• Device is regularly inspected/ maintained.• Users are fully trained in the safe use of the

device.

APPENDIX 1


However, blue light may not be the most effectiveagainst bilirubin in vivo. Longer wavelength light,in the green region, penetrates the skin further.There has been extensive debate about whetherblue or green light is more effective. Further workclaimed that using a blue-green phototherapy lightwas highly therapeutic. This work using thewaveband 480-520 nm, claimed a reduction inbilirubin levels exceeding those achieved withblue lamps. However, this technique does notappear to have been fully accepted yet by theclinical community. Care must be taken whenconsidering green light for neonatal phototherapybecause photo-toxic effects have been reported.

Area of Skin IlluminatedThe area of skin illuminated needs to be as large aspossible to maximise the efficiency of thephototherapy. Many overhead devices canilluminate up to one third of the infant's skin.Methods using a light source above and below theinfant, termed double phototherapy, furtherincrease the area of skin irradiated.

Phototherapy DevicesTwo types of phototherapy device are currentlyavailable: the conventional phototherapyilluminators, in use for over 40 years, and thefibreoptic phototherapy devices, which have beenavailable for nearly 10 years.

Conventional phototherapy equipment is either inthe form of a Tungsten halogen spotlight, a metalhalide gas discharge lamp or fluorescent lamps.Spotlights typically have ultraviolet (UV)emissions filtered out in the bulb housing toprevent unnecessary irradiation of the infant.Metal halide discharge lamps were developedfrom mercury gas discharge lamps and are housedin a canopy with separate UV filters. Fluorescenttube devices use a single tube or a set of 4 or 8tubes and again the light emission is filtered toreduce the UV component to safe levels.

The lights are positioned above or below the babyand the effective irradiance depends on thedistance between the baby and the lights. Therelationship is related to the inverse square law butis made more complex because the light is rarely apoint source. Obviously, the closer the lights canbe positioned to the infant the more effective thephototherapy. Care must be taken to preventoverheating the infant whilst ensuring that as muchof the skin is illuminated as possible. Obeying theoperating instructions is essential (MDA HazardHN9606 June 1996. See Box A1).

Fibreoptic neonatal phototherapy devices consistof a Tungsten-halogen light source, whoseemission is filtered to remove UV and infrared(IR). The remaining wavelengths are guided downa fibre optic bundle and into a flat pad of wovenoptical fibres. The pad is, therefore, cool to thetouch and may be used directly in contact with thebaby's skin or through a transparent cover. Thesepads often have a high level of irradiance but theeffectiveness can be limited by the size of the pad.

Efficiency of available systemsSeveral research studies have compared theefficiency of fibreoptic pads with conventionalphototherapy. One clinical trial used four systems

• a standard fibreoptic pad• a larger fibreoptic pad• two fibreoptic pads, one front, one back• a conventional overhead system

The double fibreoptic and the conventionalphototherapy systems were the most effective. Theeffectiveness of fibreoptic pads was lower thanconventional phototherapy in full-term infants,even though the fibreoptic irradiance was greater.The researchers attributed this effect to therelatively small area of the pad, and thus thesurface area of the baby irradiated. The authorsrecommended fibreoptic phototherapy can be usedin mild to moderate cases. High intensityphototherapy, illuminating as much of the infant aspossible, is optimum for rapid reduction ofbilirubin in severe cases.

The speed at which phototherapy reduces thebilirubin level is important for improving thehealth of the patient, reducing separation timefrom the parents and efficiently using hospitalresources. Several published reports include tables,graphs and flow diagrams to help clinicians decidewhen phototherapy is appropriate.

Side Effects and SafetyPhototherapy is generally considered a safetherapy for hyperbilirubinaemia. There are,however, a few safety issues and potential sideeffects.

The intensity of the light directed into the baby'seyes can lead to retinal damage. Therefore, when ababy is placed under a set of phototherapy lamps itis important that its eyes are covered. Twomethods are available: opaque eye pads fixed overthe eyes, or an amber coloured Perspex shieldplaced over the baby's head. There is a danger withthe eye pads that they may move and suffocate the

APPENDIX 1


baby; they have also been shown to increase theincidence of eye infection. Some research suggeststhat there is very little difference in thetransmittance characteristics of commercial and"home made" eye protection. The amber Perspexshield is more acceptable to parents, but again thebaby must be carefully monitored so that it doesnot "shuffle" out from the protective area.

During phototherapy treatment the baby'stemperature is likely to rise because there is amarked increase in skin blood flow and, to someextent, muscle blood flow. Therefore, thetemperature of a baby undergoing phototherapymust be carefully monitored. If the infant is in anincubator or a radiant warmer the potential foroverheating must be considered and the deviceadjusted accordingly. Guidelines for this are oftencovered in the incubator/radiant warmermanufacturer's instructions. In an open cot,however, an unclothed child may lose too muchheat as the phototherapy lamps are not designed toprovide a comfortable thermal environment for thechild.

Elevated skin temperature can increase insensiblewater loss from the skin. The clearance of bilirubinmay also produce diarrhoea as the bilirubinirritates the bowel and adds to total water loss.Fluid balance must, therefore, be monitored andmaintained.

Babies with hepatitis or cholestatis, where thebiliary ducts may be obstructed should not betreated with phototherapy as they may develop"bronze baby syndrome". However, this skincolouration fades a few months after phototherapy.

Rashes have been reported after phototherapy butthese have been found to be infrequent and minorand they rapidly resolve.

Parents may be concerned that their baby is"uncared for" when they see him/her being treatedwith conventional phototherapy, as the baby maybe naked, or nearly so, and have their eyesbandaged. Treatment may also be in a moreisolated part of the unit to reduce exposure to otherbabies and staff. The separation of the parents andchild both physically and through loss of eyecontact adversely affects the "bonding" process.

The use of fibreoptic phototherapy devices is oftenmore acceptable to parents and nursing staff asthey are able to nurse, feed, and cuddle the babyduring treatment. When the fibreoptic pad is usedalone the baby's eyes do not need to be covered

since the light source is placed against their back.This is also true of devices where the light sourceis positioned beneath the baby.

Nursing staff tend to find the fibreoptic devicesmore acceptable and easier to use than theconventional overhead phototherapy devices. Theintense blue light produced by overhead devicesimpedes detection of increasing "blueness" in theskin from hypoxia. Conventional overheadphototherapy devices often combat this byincluding extra lamps that allow assessment of thebaby's condition whilst being treated. One exampleis the use of "gold" lamps, which try to rebalancethe observed colour of the blue lamps. In somedevices the treatment lamp is called a "daylight"lamp as its spectrum tries to mimic daylight whilstgiving an enhanced blue component. Devices with"daylight" or colour adjusted lamps are morepleasant for the nursing staff to use. Some nursingstaff have reported experiencing headaches andnausea when working with intense blue light.

Retinal hazard to staff from phototherapy devicespositioned over incubators is insignificant. Theeffect on nearby neonates, who are not receivingphototherapy, has not been studied but it has beenindicated that it has less effect than placing thechild by a window.

ConclusionsNeonatal phototherapy has been studied in manycentres over the last 40 years. The efficiency ofphototherapy is directly related to the intensity ofthe light in the most effective waveband and thearea of infant's skin irradiated.

Conventional phototherapy devices have beenshown to produce the highest intensity and torapidly reduce bilirubin levels. Such equipmentincludes all overhead devices and the MedelaBiliBed because the technology is essentially thesame. Fibreoptic pad devices, such as theBiliBlanket, are more acceptable in use for nursingstaff and parents, but because they are currentlysmall, they are not as effective as overhead deviceswhich can illuminate more of the infant.

Phototherapy effectiveness can be furtherenhanced using either two conventionalphototherapy units, above and below the infant, ora combination of overhead and fibreopticphototherapy.

APPENDIX 2


SURVEY OF NEONATAL PHOTOTHERAPY DEVICES IN USE IN THE NHS

The spectral irradiance of devices currently in use in NHS Trusts were measured at a distance of 30 cm,if appropriate, in the range 400 nm to 550 nm. Some devices are still available and some have beensuperseded but are still in use. Phototherapy devices tend to be of simple construction with littlemaintenance required and as such are used for many years after manufacturers have ceased production.Table A1 shows a summary of devices found in use in the NHS and Figures A4, A5 and A6 show anexample of their spectral irradiance curves.

0

0.1

0.2

0.3

0.4

0.5

0.6

400 420 440 460 480 500 520 540

Wavelength (nm)

Irra

dia

nce

(m

W.c

m-2

.nm

-1)

Figure A4: Irradiance Spectrum for a Draeger Heraeus Phototherapy Unit measured at 30cm and approximately 405 hours lamp life.

0

0.02

0.04

0.06

0.08

0.1

0.12

400 420 440 460 480 500 520 540

Wavelength (nm)

Irra

dia

nce

(m

W.c

m-2

.nm

-1)

Figure A5: Irradiance Spectrum for aDraeger Phototherapy 4000 measured at 30cmat approximately 775 hours lamp life

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

400 420 440 460 480 500 520 540

Wavelength (nm)

Irra

dia

nce

(m

W.c

m-2

.nm

-1)

Figure A6: Irradiance spectrum for a VickersMedical 80/0155 measured at 30cm. - lampsapproximately 7 months old. No hour meter.

Table A1

PhototherapyDevice

Available tobuy

Irradiance inthe 400nm to550nmwaveband

DraegerPhototherapy800 - Heraeus

No

• Overhead phototherapy unit• On adjustable stand• Single mercury discharge

lamp mounted behind filtersUseful lamp life = 1000 hours

7.54 mW.cm-2

(405 hourslamp life)

DraegerPhototherapy4000

Yes

• Overhead phototherapy unit• Adjustable stand or stand

alone• 4 compact blue fluorescent

lamps and two compact"gold" fluorescent lamps.Other combinationsavailable

Useful lamp life = 1000 hours

2.81 mW.cm-2

(775 hourslamp life)

VickersMedical80/0155

No

• Overhead unit• Fixed height stand

• 4 fluorescent lamps

1.18 mW.cm-2

(7 monthslamp life)

APPENDIX 3


ACKNOWLEDGEMENTS

This report was prepared by Dr S D P Wentworth, Dr N J Cook and Dr D C Crawford of CEDAR (ClinicalEngineering Device Assessment and Reporting), Medical Physics and Clinical Engineering Directorate,University Hospital of Wales and Llandough Hospital NHS Trust, under contract to the Medical DevicesAgency.• Enquires to Dr Stephanie Wentworth, CEDAR, Cardiff Medicentre, University Hospital of Wales,

Heath Park, Cardiff CF14 4UJ. e-mail [email protected],Tel: 029 2068 2120 or Fax: 029 2075 0239 (or Tel: 01222 682120 or Fax: 01222 750239)

• Or Mr Arthur Goodman, Evaluation Manager, Medical Devices Agency, Hannibal House, Elephant& Castle, London SE1 6TQ. e-mail [email protected] 0207 972 8156 (or Tel 0171 972 8156)

We would like to thank Dr Mark Drayton, the Neonatal Intensive Care Unit and the Maternity Unit(University Hospital of Wales), Special Care Baby Units and Post Delivery units in Gloucestershire RoyalHospital, Cheltenham General Hospital, East Glamorgan General Hospital, Singleton Hospital,Eastbourne District General Hospital, Princess Royal Hospital, Haywards Heath and Salisbury DistrictHospital for their co-operation in carrying out the user assessment. With special thanks to Mr D K Taylor,Mr T Fenech, Sr M Dibden and Sr J Phillips. We also thank those, with experience in the field of neonatalphototherapy, who peer reviewed the literature review included in this issue.

We also wish to thank Dr C J Hacking for his work on this report prior to taking up a new position in theNHS.

Finally, we would like to thank Central Medical Supplies and Datex-Ohmeda for supplying samples oftheir phototherapy units free of charge for evaluation.

HOW TO OBTAIN MDA EVALUATION REPORTS

MDA Evaluation Reports are free of charge to NHS Trusts and ClinicsIn EnglandMedical Devices AgencyRoom 1207Hannibal HouseElephant & CastleLondon SE1 6TQTel : 020 7972 8181 orTel : 0171 972 8181

In ScotlandETB Support ServicesRoom D073A, ScottishHealth Care SuppliesTrinity Park HouseSouth Trinity RoadEdinburghTel: 0131 5518908

In WalesWelsh OfficeHealth Services &Management 1 DivisionCathays ParkCardiff CF1 3NQTel 029 2082 3641 orTel: 01222 823 641

In Northern IrelandDefect CentreEstate Services DirectorateHealth EstatesStoney RoadDundonaldBelfast BT16 OUSTel: 028 9052 3714 orTel 01232 523 714

DISTRIBUTION OF THIS REPORT

This report should be distributed to the following departments:Clinical Engineering, EBME, Medical Physics, Maternity, Neonatal Units, Special Care Baby Units,Nursing, Obstetrics & Gynaecology, Paediatrics, Scientific Officers, Health Authority Libraries, Supplies.

© CROWN COPYRIGHT 1999

Apart from any fair dealing for the purpose of research or private study, or criticism or review, aspermitted under the Copyright, Designs & Patents Act, 1988, this publication may only be reproduced,stored or transmitted in any form or by any means with the prior permission, in writing, of the Controller ofHer Majesty’s Stationery Office (HMSO). Enquiries about reproduction should be made to the MDA at theabove address.

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