Nigerian Journal of Paediatrics

Irradiance levels of phototherapy devices fabricated in Nigeria

Niger J Paediatr 2018; 45 (4):180 – 184

ORIGINAL

Abdulkadir I

CC – BY Irradiance levels of phototherapy

Adebiyi NM

Hassan L

devices fabricated in Nigeria

Abdullahi F

Ogala WN

Slusher TM

Vreman HJ

DOI:http://dx.doi.org/10.4314/njp.v45i4.3

Accepted: 11th November 2018

Abstract : Background: Photo-

source to meter sensor.

therapy (PT) remains difficult to

Results: The irradiance of the fab-

Abdulkadir I

(

)

deliver

many

resource-

ricated devices (F1-4) and com-

Adebiyi NM, Hassan L,

constrained countries, including

mercial device (C) measured at the

Abdullahi F, Ogala WN

Nigeria due to the unavailability

most common clinically-used dis-

Department of Paediatrics,

of devices that can deliver inten-

tance of 30 cm for intensive PT

sive PT (irradiance ≥30 µW/cm /

Ahmadu Bello University/

were 29.5 ±6.3, 30.3 ±5.3, 25.8

Teaching Hospital Zaria, Kaduna

nm) needed to treat the more se-

±5.0,49.0 ±10.5 and 39.2 ±

13.6µW/cm /nm respectively with

State, Nigeria.

vere cases of hyperbilirubinaemia.

Email:isaburamla@yahoo.com;

The basic equipment is expensive

corresponding maximum central

isaabdulkadir@abu.edu.ng

and replacement parts are often

irradiance of 36.4, 32.1, 31.2,59.5

not available.

and 54.5 µW/cm ² /nm. At a dis-

Slusher TM

Objective: To compare the blue

tance of 25cm, all devices deliv-

ered irradiance ≥ 30µW/cm /nm.

Department of Pediatrics,

light irradiance of four locally

University of Minnesota &

designed and fabricated PT de-

The cost of each local device was

Hennepin County Medical Center,

vices with a proprietary device.

less than 12% of the commercial

Minneapolis, MN 55415, USA

Materials and Methods: Four

one.

types of intensive PT devices

Conclusions: Locally fabricated

Vreman HJ

were locally fabricated. Irradiance

devices cost much less and were

Department of Pediatrics,

was measured using an Olympic

suitable for delivery of intensive

phototherapy ( ≥30 µW/cm /nm) at

Stanford University Medical

Medical Bili-Meter. The mean

Center, Stanford, CA94305-5208,

irradiance of triplicate measure-

a distance of 25cm.

USA

ments at three positions in the

light footprint of each device was

Keywords : Affordable, photother-

determine that distances of 10, 20,

apy, devices, irradiance, neonatal

30, 40, 50, 60cm from light

jaundice.

Introduction

sold for approximately between 100,000 to 200,000 and

1,500,000 to 2,000,000 Naira each respectively at an

Neonatal hyperbilirubinaemia (HB) and its visual mani-

exchange rate of 315 naira/ USD. The much higher cost

festation as jaundice occur world wide in up to 60% of

of intensive PT devices leaves most clinical services no

term newborns and in about 80% of preterm babies .

other option but procuring the far less expensive, but

Severe HB >20 to30 mg/dL total bilirubin poses a risk

inferior, conventional devices, without adequate irradi-

ance if they have any resources at all. Thus, most new-

of acute bilirubin encephalopathy (ABE) and kernicterus

in Nigeria.

2-4

born clinical services are unable to treat severe HB

quickly and effectively enough to prevent the serious

Phototherapy (PT), the principal treatment of HB, re-

sequelae of this condition.

mains inaccessible to many newborn clinical facilities in

low-income countries.

2-6

This is due to a number of fac-

In an effort to prevent such scenarios from happening in

tors, including the prohibitively high cost of PT devices

the future, we endeavored to determine if we could de-

relative to the local economy, lack of spare parts, espe-

sign, and locally fabricate, affordable PT devices that

cially lamps, and erratic electrical power delivery.

2-6

The

could deliver irradiances high enough to qualify for the

devices presently used to provide PT can be classified

delivery of intensive PT, as defined by the AAP guide-

lines.

into those providing conventional and intensive PT on

the basis of delivering irradiances of >8 to 10 and ≥

7-10

30µW/cm /nm, respectively.

We thus, designed and built four types of PT devices,

In Nigeria, PT devices are quite expensive with conven-

loosely patterned after locally used devices. We subse-

tional and intensive irradiance delivering devices being

quently evaluated their efficacy and that of a commer-

181

cially- obtained device by measuring the irradiance at

der the circuit board. Each tube is powered by 100-265

varying distances between light source and meter at

V AC and consumes up to 20 Watt of power. The LEDs

three different positions in the light foot print.

of the tube emit light at a 90 ˚ angle with a spectral

wavelength range of 400 to 530 nm, a bandwidth of 455

to 479 nm, and peak wavelength of 467 nm. Each LED

has an estimated lifetime of ~30,000hr.The fixture was

Materials and Methods

painted white, inside and out. With three tubes, it weighs

1.4kg. The tubes, which were special ordered from the

The four devices were produced by a Nigerian engineer-

supplier, each costs 8,000 Naira or US $20. The total

ing team which also ensured that all electrical work con-

cost of all parts was 134,000 Naira.

formed to mechanical and electrical safety requirements.

All devices were attached to a horizontal arm of a 4-

4. LED Tube Device with five tubes(Figure 1, F-4),is

wheeled dolly for ease of mobility. After proper train-

essentially the same as device F-3, but it is fitted with

ing, all devices were tested by the clinical staff of the

five instead of three LED tubes in order to deliver maxi-

neonatal ward as described under irradiance measure-

mum intensive PT irradiance for treatment of severe HB.

ment Protocol, below.

The weight of this device was1.8kg and the total cost of

all parts was 150,000 Naira.

Devices

5. Commercial Intensive PT Device © This is a com-

1. Fluorescent Tube Device (Figure 1, F-1) consists of a

mercially-obtained intensive PT device (Phototherapy

wood panel with fenestrations for air circulation. It has

4000 Dräger Medical GmbH, Lübeck, Germany) which

the following dimensions: 70 x 40 x 6 cm (L xW x H).

delivers irradiation in a central area (EBi) of 1.6 ±0.3

mW/cm with four blue and two white lamps and EBi of

Two sets of five opposing lamp holders were mounted 4

2.3 ±0.4 mW/cm with six blue fluorescent lights at 40

cm apart, along the short sides of the panel. The holders

were fitted with five blue light fluorescent tube lamps

cm distance. The lamps (Draeger Fluorescent light

(TL-52, T8, 60x2.5cm, 20 Watt, Philips, Eindhoven,

“blue” 2M 21 010) deliver blue light with a spectral

The Netherlands). Mechanical ballasts (Philips) were

wavelength of 400 to 550 and a peak of450nm.The fix-

mounted to supply the lamps with the necessary regu-

ture has the following dimensions: 54 x 28.5 x 13.5 cm

lated power. The lamps emit blue light with a spectral

(L x W x H) and weighs 7.2 kg It was obtained at a cost

range of 400-626 nm, a bandwidth of 403-472 nm, and a

of $4000(1,600,000Naira).

peak wavelength of 437 nm. The panel also contained

a power connector, fuse and switch. The lamps cost

Irradiance Measurement Protocol

8000 Naira each. The total cost of all materials was

120,000 Naira.

The efficacy of the fabricated and commercial devices

was determined through irradiance measurements in the

2. Compact Fluorescent Lamp Device (Figure 1, F-2):

light footprint of each device, with a handheld clinical

The lamp fixture has the following dimensions: 55 x

irradiance meter (Bili-Meter, Model 22, Olympic Medi-

29.5 x 15.5cm (L x W x H).It contains six compact fluo-

cal- now Natus Medical, San Carlos, CA, USA) which

rescent

U-tubes

(DELUX,

18Watt/71,

Blue

has a band width and peak sensitivity of 425-475 and

2G11,Osram, Muenich, Germany) spaced as seen in the

450 nm, respectively. It measures irradiance in terms of

µW/cm /nm. Specifically, triplicate measurements of

Figure. The lamps deliver blue light with a spectral

wavelength of 400 to 500 nm and peak of 460nm.The

irradiance were made at three different sites in the light

fixture with lamps weighs 5.9kg. The lamps, which have

footprint (center and two peripheral positions, 5 cm

a life span of 1000 hours, cost 8,000 Naira each. The

from each of the short edges) at 10, 20, 30, 40, 50, and

cost of all materials was 180,000 Naira.

60 cm distance from the light emission surface of the

device to the upper surface of the irradiance sensor. For

3. Light-emitting diode (LED) Tube Device with three

each distance, the irradiance was determined through

tubes (Figure 1, F-3), is based on domestication of the

calculating the mean of the triplicate measurements at

design developed by HJV using 1.5x1.5x1/16 inch

each of the three footprint sites, thus a total of 9 meas-

(2.54cm/inch) aluminum angle frame, which is readily

urements.

available and affordable in Nigeria. The dimensions are

64 x34 x 5cm(L x W x H). Inside the fixture, two sets of

five lamp holders were mounted, 6.0 cm apart, along the

opposite short edges of the frame, as seen in the Figure.

Results

The fixture also contained a fused power inlet unit with

detachable power cord, and a power switch. The fixture

The mean irradiances of the locally- fabricated devices

was fitted with three T8 custom-developed led Tubes

(F1-4) and the commercial device (C) are documented in

(Grandol Industry Ltd., ShenZhen, China) equally

Table 1. The maximum central irradiance measure for

spaced as seen in the Figure. Each 60cmx2.5cm diame-

the devices F1- 4 and the commercial device at 30 cm

distance were 36.4, 32.1, 31.2, 59.5 and 54.5µW/cm /

ter aluminum tube had nine 3-Watt LEDs mounted, 5.5

cm apart on a central circuit board. The power supply

nm respectively (Table 1). Figure 2, graphically displays

(driver) is mounted within the aluminum tube space un-

the distances at which the different PT devices begin to

182

deliver mean irradiance for intensive phototherapy indi-

cm /nm at a distance of 26 cm. The locally – fabricated

cated by the red line on the graph; devices F-1 and F-2

devices cost between 120,000 – 180,000 naira in materi-

provided irradiance of 30µW/cm /nm at a distance of

als. The cost of labour was not determined, as this is

30cm, while devices C and F-4 provided irradiance of

strongly influenced by the size of a production run.

30 µW/cm /nm at distances of 39 and 49 cm respec-

Overall none of the fabricated devices cost up to 12% of

tively. F-3 could only provide an irradiance of 30 µW/

the commercial device.

Table 1: Mean (SD) irradiance and Maximum Central Irradiance at various device distances from irradiance meter

Device

Distances (cm) between phototherapy device and irradiance meter

Cost (Naira)

F-1

80.3(17.9)

43.3(11.9)

29.5(6.3)

21.0(5.8)

14.7(2.3)

10.9(2.0)

120,000

{101}

{56.1}

{36.4}

{25}

{17.4}

{13.2}

F-2

83.8(14.1)

45.3(7.5)

30.3(5.3)

18.3(3.8)

13.1(1.5)

9.0(0.7)

180,000

{99.9}

{53.5}

{32.1}

{22.1}

{14.6}

{9.8}

F-3

40.1(9.7)

33.8(7.1)

25.8(5.0)

19.4(4.8)

16.2(3.4)

13.1(1.1)

134,000

{51.2}

{41.4}

{31,2}

{23.7}

{19.4}

{15.0}

F-4

99.9(7.6)

66.5(10.2)

49.0(10.5)

38.3(7.6)

26.1(4.6)

20.1(4.2)

150,000

{106.7}

{76.4}

{59.5}

{47.0}

{33.2}

{25.1}

69.6(69.6)

49.3(86.5)

39.2(13.6)

23.2(4.0)

15.3(1.7)

10.7(1.1)

1,600,000

{150}

{91.4}

{54.5}

{27.8}

{17.2}

{11.7}

Values are given as mean ±SD of triplicate measurements at each of three light foot print sites (n=9 measurements total).

Figures in round brackets are standard deviations

Figures in squiggle brackets are Maximum Central Irradiance readings

One Nigerian Naira = 0.04USD

Fig 2: Irradiance (µW/cm /nm) delivered by the five PT de-

Fig 3

vices as a function of distance (cm) between the device light

emission surface and detector. (Red line indicates 30 µW/cm /

nm)

Fig 4

Fig 1

Fig C

Fig 2

Fig 1; Locally fabricated (F) phototherapy devices F 1- 4 and a

commercially-obtained (C) device. F1, 2, and C use fluores-

cent lamps, while F3 and 4 use led-tubes as light sources.

Discussion

The efficacy of a PT device is in large part a function of

the deliverable irradiance to the skin of a jaundiced pa-

tient. For the efficacy to be optimal, it has to be deliv-

ered to the largest possible body surface area (BSA).

12,13

183

Thus, it is important that the light footprint of a device is

reach an efficacy plateau.

sufficiently large to cover the entire BSA. Hence, we

have built devices that all have a light emission surface

In infants with total bilirubin levels at or near exchange

area and a corresponding light footprint measuring at

blood transfusion (EBT) levels(> 20 mg/dL) or in in-

least approximately 30 x 60 cm, large enough to treat the

fants with signs of acute bilirubin encephalopathy

bodies of even the largest term newborns.

(ABE), urgently bringing down bilirubin levels is a nec-

essary strategy towards preventing the complications

Traditionally, the irradiance is measured at a distance

and sequelae of both the treatment (EBT) and the dis-

ease (ABE).

5,18

from emission surface to the top of the meter sensor

The use of intensive PT is a primary rea-

unit, the latter which should represent the level of the

son for fewer EBT’s in high income countries as com-

pared to Nigeria. The availability of these locally fab-

2,3

patient’s skin. Because the irradiance, delivered by a

point source of light, is inversely related to the square of

ricated PT devices avails clinicians in neonatal practice

the distance (Inverse Square Law), decreasing the dis-

the opportunity to improve the management outcome of

tance significantly increases a device’s irradiance, even

newborns with jaundice in Nigeria and as well possibly

if the light does not strictly originate from a point light

reduce EBT rates in the country.

source, like the TL-52 lamp. This concept is demon-

strated in Table 1, and even more so, by its graphical

There have been concerns about the use of high irradi-

presentation in Figure 2. These results show that four of

ance in the extremely low birth weight infants and con-

cerns are emerging even for term infants.

15- 17

the five devices deliver intensive PT at the most gener-

These con-

ally recommended distance of 30 cm.

cerns support the need for measuring irradiance levels

and ultimately developing protocols, which would pre-

There is no compelling reason why the distance to the

scribe the level of irradiance needed, based on the ma-

skin cannot be reduced however, care needs to be taken

turity of the infant, the risk of ABE and the need for

that lamps which run hot (often the halogen type) are

EBT. While these refinements are outside the scope of

kept far enough from an infant to prevent the skin from

the present study, the present data provide the basis for

overheating. When PT is delivered at 25cm (Figure 2),

determining the irradiance we supply with our devices

all devices will deliver intensive PT at irradiances of ≥

through adjustments of the distance between light-

30µW/cm /nm. The literature reports the use of dis-

emitting surface and the skin of the patient.

tances as short as 10 cm.

9, 14

If this distance was to be

used with the presently studied devices, the deliverable

None of the fabricated devices cost up to 12% of the

near maximal irradiance would range from 40-100 µW/

commercial device. Though the cost of labour was not

cm /nm. It is noteworthy, that the LED tube-based de-

imputed, this suggest that such devices could provide

vice with three (3) tubes (F-3), designed for treatment of

cheaper options for achieving capacity to provide cost

moderate HB(15 < 20 mg/dL), delivers the most modest

efficient intensive phototherapy in our facilities.

levels of irradiance at any distance. Use of this device

This study did not evaluate the rate of decay of the PT

lamps. Different light sources decay at different rates.

conserves LED tubes and prevents overtreatment of

newborns, especially the vulnerable preterm neonate.

The PT lamp decay is usually specified by the manufac-

turer in usage- or lifetime hours, but this parameter is

The irradiances of devices F-1, 2 and 3 clustered rela-

sometimes greatly affected by a number of factors, in-

tively together while LED tube device F-4, was clearly

cluding wide fluctuations in electrical power, ambient-

capable of delivering the highest irradiance at any dis-

and PT lamp temperatures, and types of ballast used for

tance. The commercial device (C) at shorter distances

fluorescent tubes etc. Life span of PT lamps signifi-

had very high standard deviation because the difference

cantly affects the total cost of a device over time. For

in irradiance between the central and peripheral area was

instance, LED lamps last far longer than fluorescent

quite high due to the use of white light generating bulbs

tubes (50,000 versus 10,000 hrs. and warrantees or 5-

at the extreme ends of the device. These white light gen-

versus 2 yrs.).A follow-up study, to determine the decay

erating bulbs are allegedly used exclusively for the con-

of the light sources we have tested, is planned which is a

venience of nursing personnel who have difficulty toler-

needed next step to complement this study. The frame

ating the intense blue light by attenuating it with the

design for the PT F- 1 is being reviewed to incorporate

white light and are ideally not meant to be used for PT

the use of aluminum as opposed to the wood panel to

but contrariwise usually the case in many LMICs. An

improve safety and make it fire proof.

infant undergoing PT under this device should be posi-

tioned as close to the center of the device as possible or

alternatively replace the white light tubes with blue light

tubes to optimize PT.

Conclusions

The optimum irradiance level towards reducing plasma/

Locally fabricated PT devices are less expensive.

serum total bilirubin levels per hour of therapy has not

Where protocols and guidelines dictate the need for in-

been satisfactorily established.

7, 18- 20

For many years, a

tensive PT, our locally fabricated devices proved to be

level of 35µW/cm /nm has been considered optimal,

efficient and cost effective. They are suitable for use to

however, more recent works indicate that an irradiance

provide intensive PT at an average distance of 25 cm in

of even above 55 µW/cm /nm and as high as 70 did not

our hospitals. The authors will be happy to share con-

184

struction details with interested parties.

of the Kaduna Polytechnic and his staff for their skills

and efforts towards the construction of the studied PT

devices (F1-4) and the entire staff of the special care

Acknowledgements

baby unit (SCBU) Ahmadu Bello University Teaching

Hospital Zaria, Kaduna.

We acknowledge all colleagues who worked on the

Stopping Kernicterus in Nigeria (SKIN) SLAB project.

Conflict of interest: None

We especially thank Engineer Muhammad Sirajo Lawal

Funding: None

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