High variability and low irradiance of phototherapy devices in Dutch NICUs

Irradiance footprint of phototherapy devices: a comparative study

BACKGROUND

Phototherapy (PT) is the standard treatment of neonatal unconjugated hyperbilirubinemia. The irradiance footprint, i.e., the illuminated area by the PT device with sufficient spectral irradiance, is essential for PT to be effective. Irradiance footprint measurements are not performed in current clinical practice. We describe a user-friendly method to systematically evaluate the high spectral irradiance (HSI) footprint (illuminated area with spectral irradiance of ≥30 μW cm^-2 nm^-1) of PT devices in clinical practice.

MATERIALS AND METHODS

Six commercially available LED-based overhead PT devices were evaluated in overhead configuration with an incubator. Spectral irradiance (µW cm^-2 nm^-1) and HSI footprint were measured with a radiospectrometer (BiliBlanket Meter II).

RESULTS

The average measured spectral irradiance ranged between 27 and 52 μW cm^-2 nm^-1 and HSI footprint ranged between 67 and 1465 cm², respectively. Three, two, and one PT devices out of six covered the average BSA of an infant born at 22, 26-32, and 40 weeks of gestation, respectively.

CONCLUSION

Spectral irradiance of LED-based overhead PT devices is often lower than manufacturer's specifications, and HSI footprints not always cover the average BSA of a newborn infant. The proposed measurement method will contribute to awareness of the importance of irradiance level as well as footprint measurements in the management of neonatal jaundice.

IMPACT

While a sufficient spectral irradiance footprint is essential for PT to be effective, some PT devices have spectral irradiance footprints that are too small to cover the entire body surface area (BSA) of a newborn infant. This study introduces a user-friendly, accessible method to systematically evaluate the spectral irradiance level and footprint of PT devices. This study supports awareness on the role of the spectral irradiance footprint in the efficacy of PT devices. Irradiance footprint can be easily measured during phototherapy with the proposed method.

Preliminary observations of a system for determination of phototherapy exposure over a neonate body shape

While it is possible to determine the irradiance and spectral content for a given neonatal phototherapy device at various locations over a neonate's surface, this does not allow estimation of the total rate of energy delivery within a specific spectral range over the neonate's exposed body surface. A series of 192 blue wavelength enhanced silicon photodiodes was distributed over the surface of a commercially available newborn body shape and connected to a specially designed interface circuit. Placement of photosensors over the surface of the baby shape was determined with consideration of the surface area of twelve specific anatomical areas where each was allocated 16 individual photodiodes. Calibration of detection channels for specific wavelength intervals was undertaken using a Bentham dmc150 spectroradiometer system and also a separate hand held spectroradiometer. This made it possible to estimate the effective integrated dose rate in Watts for specific wavelength intervals such as 460 nm to 490 nm as identified by the American Academy of Pediatrics for phototherapy lamp devices. This allowed identification of dose rate contributions from specific anatomical areas. Initial observations are reported for a range of phototherapy lamp systems and the findings are discussed in terms of their predicted relative clinical effectiveness. Options are also discussed in relation to the future development of the reported measurement system.

Optimization of the incubator air temperature during LED phototherapy treatment for the preterm infant

Light-emitting diode phototherapy treatment for jaundice of the preterm infant presents adverse effects, such as discomfort, changes in metabolism, and overheating. This study quantified the body heat exchanges between the environment and a simulated preterm infant requiring phototherapy treatment in a closed incubator. Phototherapy treatment increased the mean incubator roof temperature by 2.9 °C (p < 0.001) and the incubator air temperature by 1 °C (p < 0.001). Analytical calorimetry was used to calculate the additional energy received during phototherapy and thus deduce the optimal incubator air temperature for ensuring thermoneutrality and preventing hyperthermia. The optimal air temperature settings inside the incubator during phototherapy were - 0.51 to - 1.25 °C lower than references, for preterm infant weighing 500 to 2000 g.Conclusion: Phototherapy treatment for jaundice of the preterm infant increased the incubator air temperature. To prevent overheating in the preterm during phototherapy, new curves for optimal air temperature settings inside the incubator were calculated with analytic calorimetry. What is Known •Phototherapy treatment is the first-line treatment for jaundice in the preterm infant. •Phototherapy treatment increases the risk of overheating. What is New •The heat transfers and risk of overheating were quantified using a thermal manikin during phototherapy treatment. •Phototherapy treatment increased the incubator roof temperature and heat transfers. •New incubator's air temperature settings during phototherapy treatment were calculated with analytical calorimetry for preterm infant weighing 500-2000 g.

Improving Effectiveness of Phototherapy in an Academic Center: A Quality Improvement Project

Neonatal hyperbilirubinemia is a common cause of delayed discharge and readmissions in our institution. As previously published, the irradiance our phototherapy (PT) units provided was below the irradiance recommended by the AAP for intensive phototherapy (>30 µW/cm²/nm). We measured irradiance delivered by our PT units (Drager 4000) using a standardized footprint grid. By varying number of blue and white fluorescent PT lights, height of PT unit above the neonate and type of bed used (open bassinet versus isolette), we determined the optimal PT arrangement needed to deliver intensive PT (30 µW/cm²/nm). We then developed a standardized, multidisciplinary protocol specifying light arrangement and distance required needed to achieve the desired irradiance level. We were able to show improved irradiance following above changes. Onsite measurement of irradiance provided by local phototherapy units and development of a multidisciplinary, standardized protocol are necessary to assure delivery of recommended levels PT for neonates with hyperbilirubinemia.

An evaluation of phototherapy device performance in a tertiary health facility

INTRODUCTION

A range of phototherapy devices are commercially available. The American Academy of Pediatrics (2004) recommends routine intensity measurement of phototherapy devices to ensure that babies affected by hyperbilirubinemia receive effective phototherapy.

OBJECTIVE

The aims of this study were to calculate the irradiance decay velocity of phototherapy devices used in a tertiary care hospital to evaluate whether current maintenance procedures for phototherapy devices are effective, and to contribute to the improvement of a standardized maintenance procedure in daily practice, thus helping to ensure that all babies affected by hyperbilirubinemia receive prompt treatment.

METHODS

This research represents a prospective observational study conducted at Dr. Soetomo Academic Teaching Hospital in Surabaya, Indonesia from February 2019-July 2019. The intensities of 11 phototherapy devices were measured at specific times using a Bili Blanket Meter II. We calculated the Δ irradiance differences in μW/cm2/nm and calculated them as velocity μW/cm2/nm/hour of use.

RESULTS

Among the 11 phototherapy devices included in this study, nine were fluorescent and two were light-emitting diode (LED) machines. The mean (standard deviation) irradiance decay velocity of the fluorescent lamps was 0.02 (±0.03) μW/cm2/nm/hour of use, while that of the LED lamps was 0.015 (±0.007) μW/cm2/nm/hour of use. The fastest irradiance decay velocity was 0.08 μW/cm2/nm/hour of use, while the slowest irradiance decay velocity was <0.01 μW/cm2/nm/hour of use, both of which were from fluorescent-based devices. There was one fluorescent-based device that provided an intensity lower than the therapeutic level.

CONCLUSION

Irradiance decay occurred in all phototherapy device lamps. It is important to perform routinely intensity measurements, regardless of manufacturer recommendations, to avoid ineffective phototherapy resulting from intensities lower than the required therapeutic levels.

Sixty years of phototherapy for neonatal jaundice - from serendipitous observation to standardized treatment and rescue for millions

A breakthrough discovery 60 years ago by Cremer et al. has since changed the way we treat infants with hyperbilirubinemia and saved the lives of millions from death and disabilities. "Photobiology" has evolved by inquiry of diverse light sources: fluorescent tubes (wavelength range of 400-520 nm; halogen spotlights that emit circular footprints of light; fiberoptic pads/blankets (mostly, 400-550 nm range) that can be placed in direct contact with skin; and the current narrow-band blue light-emitting diode (LED) light (450-470 nm), which overlaps the peak absorption wavelength (458 nm) for bilirubin photoisomerization. Excessive bombardment with photons has raised concerns for oxidative stress in very low birthweight versus term infants treated aggressively with phototherapy. Increased emphasis on prescribing phototherapy as a "drug" that is dosed cautiously and judiciously is needed. In this historical review, we chronicled the basic to the neurotoxic components of severe neonatal hyperbilirubinemia and the use of standardized interventions.

Standardization of phototherapy for neonatal hyperbilirubinemia using multiple-wavelength irradiance integration

BACKGROUND

Phototherapy with radiation of 460-490 nm wavelengths provides the most potent therapeutic effect for neonatal jaundice. However, the efficacy of phototherapy has been estimated using single-wavelength detectors with sensitivity at approximately 460 nm. Cyclobilirubin formation capacity (CFC), which comprises the sum of the irradiance values from three wavelengths multiplied by their specific coefficients, has been proposed as an alternative marker to evaluate the efficacy of phototherapy. This study aimed to test whether two types of phototherapy devices with distinct spectral characteristics provide similar therapeutic effects on adjustment of device-to-patient distances to deliver similar CFCs.

METHODS

Using a three-wavelength spectroradiometer, CFCs and footprints of the light-emitting diode and fluorescent tube devices were assessed. Having determined the device-specific distances that ensured similar CFCs, 32 newborn infants, requiring phototherapy for hyperbilirubinemia, were randomized into the light-emitting diode and fluorescent tube groups. The total serum bilirubin levels before and after phototherapy were assessed.

RESULTS

The light-emitting diode and fluorescent tube devices had comparable CFCs at distances of 60 and 50 cm, respectively. Phototherapy reduced the total serum bilirubin levels from 18.1 to 14.6 mg/dL and from 19.1 to 15.1 mg/dL in the light-emitting diode and fluorescent tube groups, respectively. The two groups did not differ significantly with respect to the patients' clinical backgrounds, serum bilirubin levels, or changes before and after phototherapy.

CONCLUSION

At similar CFCs, the two phototherapy devices reduced the total serum bilirubin levels by comparable amounts. Hence, determining CFCs may help predict phototherapy efficacy. This may ensure better safety and greater efficacy of the treatment for newborn infants.

Current phototherapy practice on Java, Indonesia

Background

In Indonesia, the burden of severe hyperbilirubinemia is higher compared to other countries. Whether this is related to ineffective phototherapy (PT) is unknown. The aim of this study is to investigate the performance of phototherapy devices in hospitals on Java, Indonesia.

Methods

In 17 hospitals we measured 77 combinations of 20 different phototherapy devices, with and without curtains drawn around the incubator/crib. With a model to mimic the silhouette of an infant, we measured the irradiance levels with an Ohmeda BiliBlanket Meter II, recorded the distance between device and model, and compared these to manufacturers’ specifications.

Results

In nine hospitals the irradiance levels were less than required for standard PT: < 10 μW/cm²/nm and in eight hospitals irradiance failed to reach the levels for intensive phototherapy: 30 μW/cm²/nm. Three hospitals provided very high irradiance levels: > 50 μW/cm²/nm. Half of the distances between device and model were greater than recommended. Distance was inversely correlated with irradiance levels (R² = 0.1838; P < 0.05). The effect of curtains on irradiance levels was highly variable, ranging from − 6.15 to + 15.4 μW/cm2/nm, with a mean difference (SD) of 1.82 (3.81) μW/cm2/nm (P = 0.486).

Conclusions

In half of the hospitals that we studied on Java the levels of irradiance are too low and, in some cases, too high. Given the risks of insufficient phototherapy or adverse effects, we recommend that manufacturers provide radiometers so hospitals can optimize the performance of their phototherapy devices.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1552-1) contains supplementary material, which is available to authorized users.

Frequency and duration of phototherapy in preterm infants <35 weeks gestation

OBJECTIVE

To evaluate the frequency, age at phototherapy (PT) initiation, and duration of PT use in infants 23^0/7 to 34^6/7 weeks of gestation in two neonatal intensive care units (NICUs) over 4 time periods.

STUDY DESIGN

We reviewed the charts of all infants born at 23^0/7-34^6/7 weeks of gestational age (GA) and admitted to the NICUs of two hospitals between January 2009 and September 2015. We calculated the proportion of infants who received PT and the total duration of PT exposure.

RESULTS

Overall 2023 (81.8%) received PT, and PT use was inversely related to GA and birthweight. More infants received PT when GA was added as a criterion for initiating PT. The median duration (interquartile range (IQR)) of PT for all infants was 50 (27-85) h and in the lowest GA group was 74 (42-111) h.

CONCLUSIONS

Recent US consensus guidelines appear to have led to an increased use of PT in our NICUs and studies from Norway indicate that we use PT considerably more frequently and for longer durations than do our Norwegian colleagues.

Uniform national guidelines do not prevent wide variations in the clinical application of phototherapy for neonatal jaundice

AIM

This study compared the use of phototherapy for neonatal jaundice in all 21 Norwegian neonatal intensive care units (NICUs) from 2013-2014 to improve practice.

METHODS

Information on all types of phototherapy devices was collected, and irradiance was measured from random units at 20 cm and 50 cm from the light source. We gathered information on local practice rules, including the use of single, double or triple phototherapy, how infants were positioned, the frequency of blood sampling, rules for using reflective surfaces and interrupting phototherapy. In every NICU, we asked one nurse with more than five years of experience and one with less than one year to set up phototherapy equipment, then measured the irradiance and distance.

RESULTS

Photodiodes were the most common of the eight types of phototherapy devices used. Rules for the distance from the device to the infant varied from 10 to 40 cm and in practice they varied from 15 to 48 cm, with irradiance ranging from 11.1-56.1 W/m² . There were significant variations between NICUs with regard to the overall treatment duration and duration in most birthweight categories.

CONCLUSION

There were considerable variations in phototherapy practices among Norwegian NICUs. In particular, the significant variations in duration need to be addressed.

Variation in the Phototherapy Practices and Irradiance of Devices in a Major Metropolitan Area

BACKGROUND

Phototherapy (PT) is widely used to prevent and treat severe hyperbilirubinemia and its associated risks for both acute and chronic bilirubin encephalopathy. Intensive PT, recommended for inpatient treatment of hyperbilirubinemia in term and near-term infants, is defined as having a spectral irradiance of ≥30 μW/cm2/nm.

OBJECTIVES

We aimed to assess local PT practices by measuring the irradiance of PT devices in local neonatal intensive care units and newborn nurseries.

METHODS

The irradiance footprint, including maximum irradiance at the center of the footprint, of 39 PT devices in 7 area hospitals was measured according to current practice in these facilities.

RESULTS

The mean ± SD (range) footprint irradiance was 20.7 ± 5.8 (8.8-29.4) μW/cm2/nm. The mean ± SD maximum irradiance at the footprint center for all devices at a mean clinically used treatment distance of 33.1 ± 9.3 (25.5-60.0) cm was 27.8 ± 7.0 (14.7-42.0) μW/cm2/nm. Sixty-two percent of the devices did not meet the minimum recommended spectral irradiance for intensive PT. For the sites without irradiance-based protocols, the maximum irradiance of the devices (n = 33) at the treatment distances was 25.8 ± 6.1 μW/cm2/nm.

CONCLUSIONS

Despite established PT guidelines, local protocols and practices vary. Based on an assessment of 7 local hospitals, intensive PT was suboptimal for 62% of devices. Straightforward changes, such as decreasing the distance between an infant and the light source and establishing a consistent irradiance-based protocol, could substantially improve the quality of the intervention.

Irradiance levels of phototherapy devices: a national study in Dutch neonatal intensive care units

OBJECTIVE

The objective of this study is to determine whether irradiance levels of phototherapy (PT) devices in Dutch neonatal intensive care units (NICUs) increased between 2008 and 2013.

STUDY DESIGN

Irradiance of all types of PT devices, used in combination with incubators, was measured with a Dale 40 Radiometer (Fluke Biomedical, Everett, WA, USA) in all 10 Dutch NICUs.

RESULTS

Irradiance increased in seven NICUs. Median (range) irradiance increased from 9.7 (4.3-32.6) to 16.4 (6.8-41) μW cm^-2 nm^-1 for 24 overhead devices (P=0.004) and from 6.8 (0.8-15.6) to 22.3 (1.1-36.3) μW cm^-2 nm^-1 for 12 underneath devices (P=0.014). Five light-emitting diode (LED)-based devices were used in 2013 and one in 2008. The mean distance between overhead PT device and infant decreased by ~9 cm (P<0.001). Significantly more devices delivered minimal (10 μW cm^-2 nm^-1) recommended irradiance levels (80 vs ~45%; P=0.002).

CONCLUSION

Irradiance of PT devices still varies, but has markedly improved since 2008 due to shorter distances between PT device and infant, and introduction of better performing LED-based devices.

Irradiance Decay in Fluorescent and Light-emitting Diode-based Phototherapy Devices: A Pilot Study

We set out to determine the rate of decline of irradiance for fluorescent tube (FT) and light-emitting diode (LED) phototherapy devices in resource-limited settings where routine irradiance monitoring is uncommon. Irradiance levels (μW/cm(2)/nm) were measured weekly using BiliBlanket(®) II Meter on three FT-based and two LED-based phototherapy devices over a 19 week period. The two LED devices showed stable irradiance levels and did not require any lamp changes. The three FT-based devices showed rapid decline in irradiance, and all required three complete lamp exchanges approximately every 5-6 weeks. FT-based devices are associated with more rapid decline in irradiance to sub-therapeutic levels and require more frequent lamp changes than LED devices. Clinicians should be alert to the maintenance requirements of the phototherapy devices available in their settings to ensure efficacy of treatment.

Evaluation of window-tinting films for sunlight phototherapy

We evaluated nine semi-transparent plastic window-tinting films for their ability to block ultraviolet A (UVA) and infrared (IR) radiation and transmit therapeutic blue light (400-520 nm) for treating jaundiced newborns. For indoor testing, three light sources (TL/52 special blue fluorescent, Black Light UVA and IR heat lamps) were positioned above each film and measured successively using a thermocouple thermometer, UVA radiometer and blue light irradiance meter, placed below each film. For outdoor testing, the same setup was used with the sun at zenith and a cloudless sky. Compared with unfiltered radiation, blue light transmission through films ranged from 24 to 83%, UVA transmission was 0.1-7.1% and reductions in IR heat were 6-12°C and 5-10°C for heat lamp and sun, respectively. The data suggest that most of the relatively low-cost window-tinting films tested can effectively reduce sunlight UV and IR and offer a range of significant attenuations of therapeutic blue light.

Evaluation of treatment thresholds for unconjugated hyperbilirubinemia in preterm infants: effects on serum bilirubin and on hearing loss?

Background

Severe unconjugated hyperbilirubinemia may cause deafness. In the Netherlands, 25% lower total serum bilirubin (TSB) treatment thresholds were recently implemented for preterm infants.

Objective

To determine the rate of hearing loss in jaundiced preterms treated at high or at low TSB thresholds.

Design/Methods

In this retrospective study conducted at two neonatal intensive care units in the Netherlands, we included preterms (gestational age <32 weeks) treated for unconjugated hyperbilirubinemia at high or low TSB thresholds. Infants with major congenital malformations, syndromes, chromosomal abnormalities or toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis, and human immunodeficiency infections were excluded. We analyzed clinical characteristics and TSB levels during the first ten postnatal days. After two failed automated Auditory Brainstem Response (ABR) tests we used the results of the diagnostic ABR examination to define normal, unilateral, and bilateral hearing loss (>35 dB).

Results

There were 479 patients in the high and 144 in the low threshold group. Both groups had similar gestational ages (29.5 weeks) and birth weights (1300 g). Mean and mean peak TSB levels were significantly lower after the implementation of the novel thresholds: 152±43 µmol/L and 212±52 µmol/L versus 131±37 µmol/L and 188±46 µmol/L for the high versus low thresholds, respectively (P<0.001). The incidence of hearing loss was 2.7% (13/479) in the high and 0.7% (1/144) in the low TSB threshold group (NNT = 50, 95% CI, 25–3302).

Conclusions

Implementation of lower treatment thresholds resulted in reduced mean and peak TSB levels. The incidence of hearing impairment in preterms with a gestational age <32 weeks treated at low TSB thresholds was substantially lower compared to preterms treated at high TSB thresholds. Further research with larger sample sizes and power is needed to determine if this effect is statistically significant.