One study finds a shocking number of bili blue light therapy systems did not meet the minimum recommended spectral irradiance for intensive PT
For over 60 years, the use of phototherapy (PT) has been used to effectively treat hyperbilirubinemia in term and near-term infants world wide. Neonatal hyperbilirubinemia is common, with half a million or more infants effected by it annually around the globe. If not treated, hyperbilirubinemia in infants can cause a host of lasting disabilities including Kernicterus, encephalopathy, hearing loss, choreoathetoid cerebral palsy, seizures, developmental delay, and other neurological impairments. It is also linked to an increase the risk of autism.
Light phototherapy is often the first course of treatment for severe, non-genetic or illness-based infant jaundice, reducing the need for transfusions, and often allowing for treatment at a doctors office or at home rather than in a hospital setting. Light therapy is know to greatly improve infant nuerodevelopmental outcomes in the majority of cases.
Current recommendations from the American Academy of Pediatrics state that intensive PT should have at least 30 µW/cm2/nm in the bandwidth of 460 – 490 nm delivered to as much of the body surface area as possible.
Recent studies that looked for variations in the irradiance of phototherapy devices, both domestically and abroad, found a shocking number of devices did not meet the minimum recommended spectral irradiance for intensive PT. A number of factors can contribute to the deficiency including the age and condition of the light source, distance from neonate, other equipment hindering exposure to the light such as ventilators, among other things.
Why Measuring PT Light Sources Is Important
Lamp Aging - All light sources age. As it ages, a lamp's intensity (the amount of light it emits) decreases and, in some cases, its spectral output changes. Other environmental factors, such as buildup on reflectors, diffusers, and lenses, or instability in the lamp power supply, can also affect lamp performance. Also, different light sources age differently, such as LEDs versus fluorescent or halogen bulbs.
Changes to Guidelines and Specifications - The recommended spectral irradiance guidelines have changed in recent years. Today's American Academy of Pediatrics guidelines state a minimum of 30 µW/cm2/nm in the 460 – 490 nm bandwidth. Previous guidelines recommended a wider range from 430 nm to 490 nm, which is still used by many manufacturers and practitioners. Still others recommend alternative ranges, such as average irradiance in the 420 nm to 500 nm range. A recent NIH study confirmed that, for the same irradiance, a fluorescent light source with a peak near 490 nm is significantly more efficient than a fluorescent light source with a peak near 450 nm, and that using LEDs with a peak near 476 nm would be the most effective phototherapy, via Avoid absorbing unwanted light to reduce the baby's heat burden.
Differing Regional Standards – European manufacturers of blue light phototherapy devices are required to test their devices in accordance with the IEC60601-2-50 standard, where in the US no such standard exists. Additionally some European countries recommend measuring the irradiance of phototherapy lamps prior to each treatment. In the US, many hospitals and healthcare facilities have their own protocols and practices for phototherapy.
