Ambient light and phototherapy conditions of eight neonatal care units: a summary report.

Abstract

As part of the National Institute of Child Health and Human Development (NICHD) phototherapy study, a radiometric and photometric survey was conducted of the phototherapy units and the ambient lighting conditions encountered in participating centers. The survey provided a detailed description of phototherapy and ambient light conditions operative during the study and an opportunity to relate the intensities of light exposure to effects observed in the clinical trial. METHODS The survey team consisted of at least two specialists experienced in the measurement of optical radiation and a physician/pediatrician. At two of the six study centers, two separate neonatal care units were studied; thus, a total of eight neonatal care units were visited. Measurements of the intensity of the optical radiation (radiometric data) and of that optical radiation weighted for visual response (photometric data) were obtained at each location used in the study. Radiometric and photometric quantities used are listed in Table 1. Radiometric data were also obtained for at least one phototherapy unit in each neonatal care unit. Standard radiometric and photometric instrumentation and techniques were used.53,92 Instruments were calibrated with the use of light sources calibrated against standard lamps obtained from the National Bureau of Standards. The uncertainty associated with spectral irradiance measurements was estimated to be less than 35%; uncertainty for illuminance was determined to be less than 18%. (A complete description of the instrumentation and techniques used and discussion of uncertainty in the data is available on request from Biometry Branch, Epidemiology and Biometry Research Program, National Institute of Child Health and Human Development, Bethesda, MD 20205.)