Open access peer-reviewed chapter
Written By
Janet Carvajal de la Osa, Yenisel Díaz Roller and Iosvany Aguiar Ramos
Submitted: 03 August 2023 Reviewed: 05 February 2024 Published: 12 March 2024
DOI: 10.5772/intechopen.1004454
Light is a very effective tool for the treatment of neonates with problems at birth. It includes different wavelengths that can cause damage for different reasons when misused. Taking into account the characteristics of the light rays applied to neonates is important in the field of phototherapy, for the application of good clinical practices and prudent avoidance, in risk management. In this chapter, research on the application of phototherapy will be presented, highlighting the non-visible risks of using light in incubators and thermal cradles. In addition, recommendations will be made about specific aspects regarding the use and application of light for both neonate. The results show that the application of phototherapy increases the levels of electromagnetic radiation. Therefore, it must be taken into account that, although it is of vital importance for the care of preterm neonates, artificial light is a tool whose operation depends on electrical energy and represents a risk that could subsequently affect their state of health.
*Address all correspondence to: pcb@frankenthalerfoundation.org, pcb@frankenthalerfoundation.org
Jaundice is the yellowish discoloration of the skin and mucous membranes caused by the accumulation or deposit of bilirubin, which, according to clinical data, occurs in 60–70% of newborns. Some authors claim that in newborns (NB), it is a condition that can cause neuronal damage when there are excessive amounts of it, producing permanent neurological sequelae in the patient. This is why this pathological condition must be prevented by maintaining safe levels of bilirubin in the blood. To achieve these levels, phototherapy has been one of the most used techniques, through which the transformation of bilirubin into water-soluble photoisomers is achieved thanks to the effect of light on it, which allows them to be more easily excreted through feces and urine, without the need to be conjugated in the liver.
Phototherapy is a technique used in neonates to combat certain conditions that occur in them during birth, high levels of bilirubin being one of them. These phototherapy units are made up of four blue light tubes and two white light tubes. The blue ones are placed in the center, and the white ones on the sides. Light tubes or bulbs, whether LED, halogen, or fluorescent, are classified according to the maximum wavelength produced by the emitted light. Among the different types, there are: specialized blue fluorescent lamps, compact fluorescent lamps and halogen spotlights or lamps with an LED system. Some of these are also used to illuminate the work area in general.
Fluorescent tubes have plexiglass shields to filter out any ultraviolet radiation and do not emit dangerous levels of infrared radiation. LED bulbs emit blue light that does not increase temperature or emit ultraviolet radiation. However, these bulbs, with high levels of radiation, can damage the eyes and skin, so they must include internal filters and reflectors to reduce them.
According to Maxwell’s theory, light is a wavelength perturbation in an electromagnetic field in the form of radiation that propagates at a defined speed. Their characteristics are:
Light is transmitted in a vacuum at the speed of 299,792.458 km/sec, according to Einstein’s theory of relativity, comprising different wavelengths and frequencies. When the medium changes, its speed and wavelength change, but its frequency remains constant, as shown in Figure 1.
Behavior of light from one medium to another. [own creation].
The electromagnetic spectrum is nothing more than the arrangement of radiant energy according to wavelength (λ) or frequency. It extends from wavelengths of 10 16 to 10−7 m, as seen in Figure 2. At the lower end are the highest frequencies, which are the short wave and the highest energy, equivalent to cosmic rays. On the opposite side, long waves can be found, whose wavelength is highly variable and are used for radio communications, where X-ray, ultraviolet (UV), visible, and infrared (IR) rays are located.
Electromagnetic spectrum. [own creation].
It can be said that the three major regions of importance in the field of lighting are infrared light, visible light, and ultraviolet light. However, despite being so significant for human life, the visible spectrum corresponds to a tiny portion of the spectrum of electromagnetic waves. Although UV and IR rays are not detected by the human eye, their effect can be noticed physiologically. To measure the visible spectrum, the most used unit of measurement is the nanometer (nm), which is equivalent to 10−9 m.
The light spectrum is nothing more than the decomposition of white or visible light into colors that delimit its wavelengths. This ranges from ultraviolet to infrared, defined between wavelengths that range approximately from 380 to 770 nm, as can be seen in Figure 3.
Light spectrum. [own creation].
Perceived white light, as mentioned above, is a mixture of all visible wavelengths. The visible spectrum can be broken down into its different wavelengths using a quartz prism, which refracts each of them selectively through colors. The human eye separates, by capturing color, each of the different wavelengths and frequencies present in this range.
Each wavelength interval is represented by a color:
Achieving monochromatic light radiation, that is, one that responds to a single wavelength, is very difficult. The light sources that most closely resemble this type of emission are the laser and the low-pressure sodium lamp.
Radiant energy is made up of electromagnetic waves with a range of frequencies (ѵ) ranging from 108 to 1024 s−1 and propagates at a constant speed (of light), whose value is exactly 299,792,458 m/s.
White light is the result of the sum of countless wavelengths that, when added, become colored rays, giving rise to the perception of the color white. As stated by Mosquera Torres et al., white light is 25% blue light.
Most lamps intended for lighting work areas in the health sector emit white light. This condition is necessary for the safety and protection of management and the health of both patients and workers.
Basically, phototherapy applied to neonates with conditions at birth is based on the use of blue and white light. Wavelengths between 380 and 500 nm include the violet, blue, and green areas of the spectrum. This part of the spectrum is also known as high-energy, short-wavelength visible light.
Sunlight is the main natural source of blue light, although there are enough sources of artificial blue light for humans to be exposed 24 hours a day. In 2013, a panel of American experts pointed out that solar radiation is 25–30% blue light, as shown in the spectrum in Figure 4.
Representation of the daylight spectrum. [own creation].
All artificial light sources have blue light in their spectrum in different percentages; thus, conventional incandescent light lamps have the least with around 3%, low consumption compact fluorescent lamps at approximately 26%, and LED lamps, which emit cool white light, blue light is 35% one of the strongest components, as shown in Figure 5.
Representation of the spectrum of some artificial light sources. [own creation].
Jiménez-Rubio et al. mention that blue light provides benefits to the synchronization of circadian cycles and the production of melatonin, if it is properly provided during the day and night cycles, also as it has been shown to provide the newborn with high levels of bilirubin an effective treatment, but at the same time, it must be taken into account that the indiscriminate use of this type of light poses specific risks to vision and skin that are irreversible due to its power of penetration into biological material.
For their part, studies carried out in the last decade have suggested that phototherapy is associated with type 1 diabetes, damage to the immune system, leukemias, and asthma as late and long-term effects. The relationship, according to these investigations, is due to the fact that by applying phototherapy 24 hours a day, the neonate is inhibited from producing what is necessary to raise the immature immune level. This situation, as stated by Boidi, causes a deficiency of T lymphocytes, molecular alterations in the DNA of mononuclear leukocytes, alterations in the concentrations of interleukins that tend to slow down the change in an immune response, increasing the risk of suffering in the long term—the mentioned diseases.
Currently, there are no standards that standardize adequate light levels in a Neonatal Intensive Care Unit (NICU), as this structurally depends on the geographical characteristics of the place, the type of care provided in the unit, and the design and location of the Windows. Additionally, the condition of the newborn and its location within the area must be taken into account.
For premature babies, reducing light, as well as maintaining the light and dark cycle, is of vital importance, which is why it is convenient to have intensity regulators to adjust the light power depending on the needs that arise daily around them. Him.
As recommendations to maintain the minimum lighting conditions, it is adopted that, during the day, the light oscillates between 100 and 200 lux, preferably supported by natural light and, at night, artificial light of approximately 50 lux, but allowing it to be adapted between 10 and 600 lux independently depending on the case. If a short-term evaluation of a specific RN is necessary, between 1000 and 1500 lux can be used, avoiding interference with nearby children.
In nursing work areas, it is advisable to have moderate levels of lighting with the possibility of regulation and during the day to take advantage of natural light, somewhat distorting its direct action on the work area.
Today, there are several modalities of phototherapy such as:
The effectiveness of phototherapy depends on the irradiation of the light source. Irradiance is expressed in units of watts or microwatts per square centimeter per nanometer (W/cm 2/nm) (μW/cm 2/nm), respectively, within a given wavelength band.
Depending on the maximum wavelength produced by light and the hours of exposure to it, there are different types of phototherapy, such as:
