Medicines and Healthcare products regulatory Agency logo Evaluation report EVALUATION MHRA 04143

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1 Medicines and Healthcare products regulatory Agency logo Evaluation report December 2004 EVALUATION MHRA Natus neoblue LED Phototherapy System Department of Health logo best choice best practice. nww.medical-devices.nhs.uk

2 About MHRA evaluation reports. What you can expect. The Device Evaluation Service (DES) aims to provide independent and objective evaluations of medical devices available on the UK market. Specialist centres, mainly in NHS Trusts, do the evaluations under long term contract to, and in accordance with protocols approved by, the Medicines and Healthcare products Regulatory Agency (MHRA). The evaluations are usually of a unit supplied by the manufacturer. We would expect this unit to be representative of the product on the market but cannot guarantee this. Prospective purchasers should satisfy themselves with respect to any modifications that might be made to the product type after MHRA s evaluation. The reports are intended to supplement, not replace, information already available to prospective purchasers. The MHRA DES does not have access to any information held by the Agency in its capacity as the Competent Authority for the UK, apart from any information already in the public domain. The reports will contain data given by the manufacturer on the regulatory status of their devices but, apart from this, they are not an indicator of the regulatory status of a product. Occasionally, DES refers products to the regulatory arm of the MHRA for considerations of breaches of the legislation governing medical devices. DES plays no further part in any regulatory investigation that ensues and does not have advance notification of any regulatory action that may follow. How to obtain MHRA reports. To order evaluation reports, a copy of the publications catalogue, or to sign up for our alert service contact: MHRA Orders Department, Room 1207, Hannibal House, Elephant & Castle, London, SE1 6TQ. Tel: Fax: des@mhra.gsi.gov.uk Visit for a comprehensive list of publications, details of forthcoming evaluations, services and contacts. Colour reports. Full colour versions of all reports published after 2002 are available from the NHSNet at: nww.medical-devices.nhs.uk

3 Natus neoblue LED Phototherapy System Dr Stephanie Wentworth, Steven Edwards, Dr Diane Crawford CEDAR (Clinical Engineering Device Assessment and Reporting) Cardiff Medicentre University Hospital of Wales Heath Park Cardiff CF14 4UJ Tel: Fax: or For more information on CEDAR visit Crown Copyright 2004 Apart from any fair dealing for the purposes of research or private study, or criticism, or review, as permitted under the Copyright, Designs & Patents Act, 1998, 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 of Her Majesty s Stationery Office (HMSO). Information on reproduction outside these terms can be found on the HMSO website ( or hmsolicensing@cabinet-office.x.gsi.gov.uk. The MHRA is an executive agency of the Department of Health. ISBN [ ]

4 Contents Summary Summary Advantages Disadvantages Introduction Description User Assessment Clinical user assessment Technical assessment Evaluator comments Acknowledgements References Appendix Questionnaire Neonatal phototherapy evaluation reports Manufacturer s data Manufacturer s comments

5 Summary Paediatric intensive care forms part of the Department of Health National Service Framework and Getting the right start: National Service framework for Children - Emerging findings specifies the need for services to care for babies with specific needs, eg prematurity or disability [1]. CEDAR evaluates neonatal intensive care equipment as part of this National Service Framework and began an evaluation series on neonatal phototherapy devices in 1999 (see Appendix for further details). The Natus neoblue LED Phototherapy System is the first phototherapy device using light emitting diodes (LEDs) to be commercially available in the UK. The use of LEDs in phototherapy devices allows greater control over the wavelength of light which, theoretically, may improve the efficacy of the phototherapy treatment. All other currently available devices in the UK use fluorescent tubes, halogen lamps or other gas discharge lamps. The neoblue was evaluated as a full single product evaluation project. Both technical and user assessments were carried out following CEDAR s phototherapy device protocols. Measurements were made of irradiance and inadvertent heating effects and a survey, involving 35 clinical staff from three hospitals, showed that overall they rated it s facilities as satisfactory or better Advantages The neoblue is easy to use and is comparatively light and easy to move, with a stable wheelbase. The LED light source emits no UV, has a long lamp life and low heat output. Technical users have commented that it is easy to maintain. Disadvantages Positioning the lamp head can be difficult when using a radiant warmer. Tilt* can be difficult to operate. Some users found the glare* gave them headaches. Light output on Low power setting is only adequate (1mW.cm -2, [2]) at the recommended minimum treatment distance of 30cm. *see manufacturers comments Price ex VAT 2,800 Manufacturer Supplier CE Marking neoblue summary data Natus Medical Inc Natus Neonatal Ltd. Yes Notified body TUV 0197 Manufactured to Standard EN , EN , EN UL2601-1, CSA

6 Introduction Neonatal phototherapy is a non-invasive therapy used for treating neonatal jaundice, also known as hyperbilirubinaemia. The build up of bilirubin, which causes neonatal jaundice, can lead to brain damage and death. Light in the blue/blue-green region of the visible spectrum interacts with bilirubin in the neonate s skin to produce isomers of bilirubin that the neonate can excrete. Neonatal phototherapy is well tolerated and is used clinically throughout the UK. This report provides an independent source of information on this new device. For a detailed description of neonatal phototherapy please see evaluation MDA 391, 2000 [3]. The three important factors in neonatal phototherapy [4]: irradiance, effective wavelengths of light and surface area illumination form the basis of CEDAR s technical testing. Irradiance should be as high as possible and this is measured at the manufacturers recommended treatment distance; the effective waveband is still an area of controversy and CEDAR s measurements encompass UV through to the visible band in order to allow calculation of the irradiance in all of the bands cited in literature. The phototherapy evaluation series has quoted irradiance in the waveband 400 to 550nm although it is recognised that this is broad. The light should illuminate as much of the infant s skin as possible. For many single lamp head devices this amounts to up to one third of the infant s total surface area. The light field area produced by the lamp at the treatment distance is quoted as a guideline. LEDs are semiconductor devices that emit light when an electric current passes through them. A semiconductor is a substance, usually a solid chemical element or compound, that can conduct electricity under some conditions but not others. This makes it a good medium for controlling electric current [5]. The wavelength of light emitted depends on the semiconductor used and the impurities added (doping). Research work on LEDs is continually refining the ability to select the wavelength emitted by careful structural and doping changes to the diode junctions. Examples of materials used to make LEDs include aluminium gallium arsenide (AlGaAs) for red and infrared LEDs and indium gallium nitride (InGaN) for blue LEDs. The efficiency and brightness of LEDs have improved dramatically over the last 5 years, in particular in the blue spectral region. Blue LEDs were unavailable a decade ago because the semiconductor alloy needed to achieve a blue wavelength was not fully developed. New semiconductor chemistry based on gallium nitride (GaN) enabled high efficiency blue LEDs to rapidly emerge from the laboratory into the marketplace. A new GaN alloy now yields very high brightness blue emission [6]. Early blue LED phototherapy devices were found to become hot [7]. More recent developments of blue LEDs, of sufficient brightness but without overheating, have enabled prototype development [8,9] and the production of commercial blue LED phototherapy devices such as the Natus neoblue. LEDs placed close to the infant can deliver irradiance levels of over 200µW.cm -2.nm -1 [9]. 2

7 Description The Natus neoblue is built as a conventional phototherapy device, an array of lights on an adjustable stand (see Figure 1). The device has a simple on/off switch on the back, and the stand is constructed so that the position of the lamp head may be adjusted vertically and horizontally extended. The head may also be tilted by loosening a bolt with a supplied allen key. Older versions of the neoblue seen during the user assessment had a different mechanism for tilt adjustment (see manufacturer s comments). The head has 852 blue LEDs, 320 yellow LEDs and 13 red LEDs. The blue LEDs provide the treatment light. The yellow LEDs provide colour balance, to make the lamp easier on the users eyes, and the small central section of red LEDs are for centralising the lamp head. The light has two settings, high and low intensity, and the yellow lights remain on during both. The red LEDs are only lit when the toggle switch, shown in Figure 2, is held down. The wheelbase on the sample seen for evaluation (see Figure 1) has five wheels, two of which have locks. This wheelbase is built to be very low and Figure 1: neoblue phototherapy light switched on and mounted on a stand. has a height of 9cm. A different wheelbase was seen in some neonatal units during the user assessment. There is no timer on this phototherapy device, but the manufacturer states that expected lifetime of the LEDs is 10,000 hours on low power and 3,000 hours on high power. The blue LEDs are arranged and connected in banks of 6 lights, if one LED stops working the bank of six LEDs will go out. The yellow LEDs are in groups of 10. High power Low power Figure 2: neoblue head showing the switches Red centralising light toggle switch 3

8 User Assessment Clinical user assessment Thirty three nurses, one health care assistant and one staff grade registrar in three hospitals participated in our user assessment. Thirty users had used the neoblue for over a year, four users had used it for six months, and one user for three months. Users were asked to rate features as unacceptable, poor, satisfactory, good or excellent in our questionnaire. Written comments were invited in a space beside each question. General questions on training received, how often they had used the neoblue and what they considered were the advantages and disadvantages of the device were also included. Users were also asked what other phototherapy devices they had used to indicate any unspoken comparisons they may have been making. To clarify issues raised an evaluator visited each neonatal unit. The response of the users is shown in Figures 1 and 2. The numerical data response from the questionnaire is reproduced in the Appendix for interested readers. Overall the lamp was well liked and the majority of users scored all features as satisfactory or better. No. of respondents Figure 3: Response to questions 1 to 6 The mobility of the stand was scored highly by most users although some commented that the feet stuck out and that it was difficult to get under some incubators (see manufacturer s comments). During the user visits it was observed that each hospital had at least one neoblue with a different stand base to the sample neoblue evaluated. This other stand had a higher wheelbase height of 12.5cm; the wheelbase of the sample evaluated was 9cm. In one hospital the senior 4

9 User Assessment No of respondents Figure 4: Response to questions 7, 9, 10, 11 and 12 nurse demonstrated how difficult it was to get the higher wheelbase under the C550 Isolette incubator, but it was easy to slide under other incubators. The higher wheelbase stand also had two feet which stuck out further than the other three. Both stands had five feet in all and two wheels with locks. CEDAR Note: The higher wheelbase was the original version, the lower profile base has been developed by the manufacturer, in response to customer comments. All of the users thought the device was very stable and they liked the vertical height adjustment, five nurses rated this as excellent. The tilt adjustment was liked by most users but two considered it poor and one unacceptable, commenting that it was difficult to use (see manufacturer s comments). During the user visits the neoblues in use were observed to have a different mechanism for tilt adjustment which involved a small handle. CEDAR Note: neoblue Version 2 was seen for technical evaluation and the tilt mechanism had been altered in response to customer comments The on and off switch was liked by most users although a few commented that it had to be looked for and that it would be better on the front or side. CEDAR Note: we consider this to be because the neoblue switch, being on the back, will often not be visible during use and may be difficult to find by touch alone. The high and low power switch was rated as satisfactory or better by all users and the centralising red light was rated as excellent by four nurses. The neoblue was considered by users to be effective with good light output. Glare was the worst rated feature. The majority rated it as satisfactory or better but nine users rated it as poor or unacceptable, commenting that it gave them 5

10 User Assessment headaches.(see manufacturer s comments). CEDAR Note: Intense blue light is acknowledged to make some people feel nauseous, dizzy or develop headaches. The user manual suggests use of yellow glasses to reduce the effect of the glare. The response to question 8 has been plotted separately as a pie chart (Figure 5) in order to demonstrate the different ways in which the light output was used. The majority of users, 68%, used the high power setting, but 12% used only the the low power setting. CEDAR Note: Light output at low power setting is only adequate for phototherapy (1mW cm -2 [2]) at the minimum recommended treatment distance of 30cm. (see Technical assessment for irradiance measurements at high and low power). The neoblue was considered easy to clean with no awkward areas. Figure 5: Response to question 8:Which lamp configuration do you use? All but one user reported that they had received training from the supplier or colleagues. When asked about the overall advantages of the unit, most users stated that it was not necessary to give the patient extra fluid while using the neoblue. Some other users also noted that when the neoblue was used over an incubator they did not need to adjust the temperature of the incubator. They commented that with other phototherapy devices the incubator sometimes became too hot and alarmed. Users also stated that the relatively small size of the neoblue was an advantage. The overall disadvantages noted included the glare and the difficulty in getting the wheelbase under some incubators (see manufacturer s comments) 6

11 User Assessment Technologist user assessment During each of the three hospitals visits the local Clinical Engineering department s opinion of the neoblue was sought. The neoblue in these hospitals has been in use for nearly two years, the first unit being bought in January The general opinion of the technologists was that the neoblue was an easy device to maintain. None of the neoblues in the hospitals surveyed had needed a repair or replacement LEDs. However, the technologists expect this to be necessary within the next year to 18 months. CEDAR Note: The neoblue has no timer so it is not possible to compare the number of hours in clinical use for each machine to the expected lifetime of the LEDs. One technologist considered cleaning the neoblue to be a fiddly job. He found it necessary to open the neoblue because the filters did not keep out all of the dust. Another equipment service manager commented that having a closed and sealed unit was an advantage because insects did not get inside. Insects had been found inside other phototherapy devices with more open design lamp heads at this hospital. All of the clinical technologists had developed a service schedule and measured the light output at regular intervals as suggested in the user manual. A potentiometer may be adjusted to increase light output, details are in the service manual. No servicing manual was available to the technologists at the time of the user visit but guidelines were found in the user manual. CEDAR Note: A service manual is now available from Natus UK. Manuals The user manual and service manual are both available in PDF format. They contain detailed information and diagrams. They do not specify the wheelbase or the tilt mechanism but these areas appear to have been left open and have indeed been changed during the time the device has been on the market. 7

12 Technical assessment Our technical tests were designed to assess the clinical performance and safety of this device. The light output (irradiance), the wavelengths of light emitted and the effective treatment area are of prime importance. Baby heating effects have been associated with phototherapy lamps prompting us to measure the heating effect of this lamp in a clinical simulation. The irradiance from the neoblue was measured using a Bentham double monochromator spectroradiometer with teflon cosine diffuser. The spectroradiometer was set to measure the intensity of the light at one nanometer steps in the 300nm to 700nm waveband. We selected this waveband in order to collect data in the: ultraviolet A waveband (320nm to 400nm), the blue light waveband (400nm to 550nm) known to include the effective waveband for bilirubin clearance, and the longer visible light waveband (550nm to 700nm), light in this waveband and especially above 600nm indicates that there may be an inadvertent heating effect from the lamp. Irradiance measurements in these bands have been made throughout the phototherapy evaluation series and allow direct comparison of technical performance. We made irradiance measurements at distances of 15cm to 60cm, in 5cm increments, to determine how the irradiance varied with distance from this lamp. The results at 30cm and 40cm are tabulated here for direct comparison with other phototherapy devices evaluated (see Table 1). Natus recommend 30cm as the minimum treatment distance, including a 5 cm air gap above the top of the incubator surface to allow air circulation. They state that the irradiance of the neoblue at 12 inches (30cm) should be in the range 30 to 35 mw.cm 2.nm -1 as measured with an Ohmeda BiliBlanket R Meter II. Unfortunately no information is given on the response Table 1: neoblue performance data Bandwidth (nm) 320 to 400nm (UVA) 400 to 550nm (blue/blue/green) Effective surface area ie where irradiance >1mW.cm -2 (400nm to 550nm waveband) at 30cm Irradiance through air at 40cm High power 0.00mW.cm -2 Low power 0.00mW.cm -2 High power 0.00mW.cm -2 Low power 0.00mW.cm -2 High power 2.29mW.cm -2 Low power 1.00mW.cm -2 High power 1.86mW.cm -2 Low power 0.79mW.cm -2 High power 3100cm 2 High power 2800cm 2 Low power 500cm 2 Low power 0cm 2 8

13 Technical Assessment window of the meter. We also use 40cm since this is the approximate distance of an incubator canopy from the mattress. We have used this as a standard comparative measure across the phototherapy device evaluation series (see Appendix). The Natus neoblue may be operated in either high power or low power mode. The spectra for high and low power at 30cm are shown in Figure 6 and also again for low power at 40cm, this third spectrum includes the light from the red LEDs. The large peak between 430 and 490nm is as expected from the blue colour of the lights. A smaller peak at 590nm is a result of the yellow LEDs. The even smaller peak at 640nm is the light from the red LEDs used for centralising the lamp head. The small red component of the spectra is shown here for completeness, these centralising lights are only activated briefly when the toggle switch is held on. They are not left on permanently during treatment. High 30cm Low 30cm Low 40cm with red LEDs on Figure 6 Spectra for the neoblue The spectrum was also measured through an incubator canopy. Most neonatal phototherapy lamps are used over incubators and this test was considered a clinical simulation. The incubator canopy was found to make little difference to the irradiance reaching the detector. During these measurements of the spectrum, a hand held IL1400A radiometer was also used. This has a response window of 400 to 490nm and gave a direct comparison with the spectrum from the spectroradiometer. In neonatal phototherapy there are three important factors for effective treatment [3]: effective waveband (400 to 550nm), irradiance (should be greater than 1mW.cm -2, 9

14 Technical assessment [9]) and effective light field area (illuminate as much of the baby as possible). Using the hand held radiometer the effective light field was mapped out. The neoblue was positioned at 30cm and then at 40cm and for each setting the light field was mapped at 5cm intervals over a grid area 75cm by 80cm. The effective light field, where irradiance is greater than 1mW.cm -2, is approximately 2800cm 2 at 30cm, and 3100cm 2 at 40cm on high power. On low power it is only 500cm 2 at 30cm and at 40cm the irradiance did not achieve the 1mW.cm -2 limit, see Table 1. Heat from the lamp head at the mattress was measured using three matt black aluminium discs with platinum resistance thermometers inside them, as used for measuring the temperature under infant radiant warmers [10]. These discs were placed in the centre of the light field. The lamp was turned on and the temperature monitored for nearly 6 hours. With the lamp head 40cm from the black discs a temperature rise of 3 C was measured. This is a small temperature rise but it is important that the neonatal nurses are aware of it. The noise level from the neoblue was 49±1db(A) inside an incubator canopy. Background noise level was 35±1dB(A). This is a good result, it s noise level is quieter than the operation noise level of many incubators and well below the noise level limit for phototherapy devices, 60 db(a) [11]. Neonatal units should be as quiet as possible [12]. Evaluator comments The neoblue was an easy to use, easy to move, stable device. The light output was uniform across the treatment area but the irradiance values were lower than expected given the output levels which have been reported from blue LEDs [9]. Light output on the low power setting was particularly low as, from current UK guidelines[2], irradiance should be >1mW.cm -2. The low power irradiance at 30cm only just met this criteria when the irradiance was measured in the 400nm to 550nm waveband. At 40 cms treatment distance the irradiance would require a 26% increase in light output to achieve the minimum recommended level. Commendably, the heat produced by the lamp head was low and this may be why the users did not need to give the patients extra fluids. 10

15 Acknowledgements We thank all the nursing, clinical and technical staff in the neonatal units at: The Derriford Hospital, Plymouth The Whittington Hospital, London King s College Hospital, London for their help in carrying out the user assessment. We would also like to thank Norma Greene for her administrative help. Thanks also to David Taylor and Gloucestershire Royal Hospital for the loan of the spectroradiometer, and to Graham Hart for helpful discussions. Finally we would like to thank Natus UK for loaning this device for evaluation free of charge. 11

16 References Department of Health. HEI No 202 September /92:12 3 MDA 391 A review including the Ohmeda BiliBlanket Plus and the Medela BiliBed Medical Devices Agency, Maisels MJ. Why use homeopathic doses of phototherapy? Pediatrics 1996; 98: (last accessed 29/09/04) 6 (last accessed 30/09/04) 7 Dicken P. Light Emitting Diode (LED) Neonatal Phototherapy. MSc Thesis University of London, Vreman HJ, Wong RJ, Stevenson DK, Route RK, Reader SD, Fejer MM, Gale R and Seidman DS Light -emitting diodes: A novel light source for phototherapy Pediatric Research 44: Seidman DS, Moise J, Ergaz Z, Laor A, Vrenman HJ, Stevenson DK and Gale R. A new blue light emitting phototherapy device: A prospective randomised controlled study. The Journal of Pediatrics : BS EN :1997. Particular requirements for safety: specifications for infant radiant warmers. BSi; BS EN :2002. Particular requirements for the safety of infant phototherapy equipment. BSi; March Zahr LK and de Traversay J. Premature infant responses to noise reduction by earmuffs: effects on behavioral and physiologic measures. Journal of Perinatology 1995; 15:

17 Appendix Questionnaire Table A1: User assessment data from questionnaire. The number of users sharing the same opinion about a feature, e.g. 23 users thought the mobility of the stand was good. The most common response is marked in bold. For some features only a few users scored their opinion on their questionnaire. Number Question Unacceptable Poor Satisfactory Good Excellent 1 What is your opinion of the mobility of the stand What is your opinion of the stability of the stand What is your opinion of the vertical height adjustment of the stand? What is your opinion of the tilt adjustment of the lamps? Please indicate your opinion of the on/off controls on the back of the phototherapy light unit Please indicate your opinion of the high/low brightness control (indicates as(** and *) on the front of the phototherapy unit. Please indicate you opinion of the red centralising light activated by holding the right hand switch down Please indicate which lamp configurations you use 9 What is your opinion of the light output from the lamps Please indicate your opinion of any glare from the lamps Please indicate how effective you consider the phototherapy device to be Please indicate your experience of cleaning the device Did you receive training from the manufacturer / supplier / sales representative? Yes = 6 No = What was your opinion of that training Have you read the user manual Yes = 4 No = What was your opinion of the user manual? Did you receive training from colleagues in your hospital Yes = 13 No = 4 13

18 Appendix - phototherapy evaluation reports Neonatal phototherapy evaluation reports Table A2: Neonatal phototherapy evaluation series, reports published by the MHRA to date Draeger Phototherapy 4000 December Medela Phototherapy Lamp December Mediprema Cradle 360 December Ohmeda Spot Lamp May Hill-Rom Micro-Lite January A review including the Ohmeda BiliBlanket Plus and the Medela BiliBed April

19 Appendix - manufacturer s data & comments Manufacturer s data Manufacturer Natus Medical, Inc., 1501 Industrial Road San Carlos, CA , USA Country of Origin USA Supplier Prices (ex VAT) Natus UK, Hampden House, Monument Business Park, Warpsgrove Lane, Chalgrove, Oxford, OX44 7RW Tel: Fax: Natus UK is the trading name of Natus Neonatal Ltd. Lamp and stand Replacement LED panel 2,875 1,200 Manufacturer s comments Those hospitals involved in the User Assessment had over 12 months experience of the using neoblue TM system but most were familiar with the first generation product. The neoblue TM system evaluated technically was a Version 2 neoblue TM device and is the model currently available for purchase in the UK. This incorporates several improvements which address the adverse comments in the user assessment. The following improvements are found in Version 2 : 1 yellow/amber lights have been incorporated to reduce visual glare from blue LEDs and lower the risk of headaches for clinical staff sensitive to blue light. 2 low profile wheeled base, improves positioning under incubators 3 tilt mechanism is now adjusted with an allen key, supplied with the lamp. Clinical results from the two versions are equally good. Both deliver high intensity, blue light per the recommendations in the 2004 AAP Guidelines for Phototherapy. Unlike fluorescent and halogen bulbs, the stated intensity of light emitting diodes (LEDs) last thousands of hours so frequent replacement is not necessary. The light intensity can be increased by up to 15% using a potentiometer (see user and service manual). This can be used to compensate for reduced output as LEDs lose intensity and for treatment distances greater than 30cm. By utilising a narrow band of blue light, the neoblue TM system may potentially reduce treatment times. We have been told, anecdotally, that our light helps drop bilirubin faster than competitive systems. 15