Friday, July 27, 2018

Light and Acoustic Environment In NICU



Lighting
Planning appropriate lighting for the NICU requires consideration of the disparate needs of both the babies and staff. In general, babies need very little light, but exposure to moderate levels of   illumination during part of the day may help establish circadian rhythmicity.

The lighting will be different in many areas in the NICU as illumination of a procedure area will vary from other ambient lighting situations. Flexibility in lighting levels is required as infants' needs change at different stages of development. Control of illumination should be accessible to both staff and families, and the design should include multiple light switches. If linear fluorescent lamps are used, the color designation should be “RE80.” All fixtures should have filters or shields that block ultraviolet radiation and minimize the risk to babies and staff if a bulb should shatter.

Staff need moderate levels of illumination at the bedside to evaluate babies and to perform charting and manual tasks.
At times, intense levels of illumination are necessary to perform procedures and for phototherapy of hyperbilirubinemia. 
It is doubtful that babies need natural lighting, but studies of adult office workers and hospital patients document the benefit of windows for staff and families. A multilevel lighting scheme should be considered by the design team:

1. Ambient lighting in infant care areas.
Lighting levels are adjustable through a range of 10 to 600 lx (1 to 60 foot-candles) as measured on a
horizontal plane. A control thermistor should allow for immediate darkening if necessary. Electric light sources should have a color rendering index (CRI) of no less than 80 and a gamut area index (GA) of no less than 80 and no greater than 100. The optical reflectors in the light fixture shall have a neutral finish  and unnecessary ultraviolet or infrared radiation shall be avoided. Any ambient lighting utilized should avoid the infant's direct line of sight.

2. Procedure lighting in infant care areas.
Separate procedure lighting should be present at each infant bed and be capable of providing no less
than 2,000 lx. In addition, the light output must be framed to exclude extension beyond its illumination field. Temporary increases in illumination may be necessary for clinical evaluation or performing a procedure. It is important not to increase lighting levels for adjacent babies. Intense light may be harmful to the developing retina. It is best to permanently mount a procedure light than to have a free-standing floor light, so that space can be maximized and accidents avoided.


3. Illumination of support areas.
All support areas (e.g., charting, medication preparations, hand washing, reception) shall conform to
current Illuminating specifications. At times the areas in the NICU may overlap; if infant care areas are close to charting space, it is important to make sure that the lighting does not reach adjacent infants.

4. The importance of daylight
At least one source of natural daylight shall be visible from an infant's space or room. If an exterior
window provides this light, the window shall be glazed with insulating glass to minimize heat gain or loss and shall be situated at least 2 feet away from any part of an infant's bed. Shading devices with neutral colors are necessary for external windows. Windows providing daylight provide an important
psychological benefit to both staff and families; however, radiant heat loss or gain may occur if babies are placed too close to an external window.

Acoustic Environment
We have learned a great deal concerning the acoustic environment and the effect of noise on the
development of newborn hearing. The entire NICU environment has both operational sound and
background noise. It is a challenge to design a facility where the combination of background noise and operational sound should not exceed an hourly Leq of 45 dB and an hourly L10 of 50 dB in infant rooms and adult sleep areas. In other parts of the NICU (staff, family and lounge), these levels can be somewhat higher.
Mechanical sources of noise (not including medical equipment) include heating, air-conditioning, plumbing, vacuum tubes, freezers, refrigerators, and communication systems. Remember too, that pipes, ducts, and other conduits can produce noise. Airflow through the heating and cooling ducts can produce considerable background noise in an NICU, but this can be reduced by appropriate sizing and baffling of the ducts. These issues must be addressed in the design process, because it is prohibitively expensive to correct a poor design after construction begins.
Some NICUs are situated in noisy communities, which require extra insulation in the external walls to minimize the impingement of outside sounds into the NICU. Audible telephone noises, alarms (even fire alarms) and water flow through pipes can also increase the amount of background noise.
Traffic patterns also play a role in determining the level of noise to which babies and staff are exposed. To the greatest extent possible, traffic flow should be designed so that an echocardiogram, ultrasound, x-ray, or electroencephalographic technician can get to each baby's bedside as directly as possible, without wheeling the equipment past several other bed positions.
We believe an acoustical engineer should be part of the design team to assure that the acoustic
environment satisfies all current standards.
Finally, care practices should be evaluated as part of the design process to see whether sources of noise produced by the staff can be diminished or eliminated. Radios, pagers, rounds, and reports are examples of care practices that may create considerable noise at the bedside and that can be modified or eliminated. 


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