Neonate and Noise

Premature babies are fragile. One of their special needs is quiet time. In utero, the fetus is in deep sleep approximately 80% of the time with very few interruptions.1 However, in the neonatal intensive care unit(NICU), high noise levels and frequent handling leave the babies sleep deprived and may disrupt their normal growth and development.2 Furthermore, noise in the NICU environment is considered a factor in altering the behavioral and physiological responses of infants and may be responsible for some developmental disabilities and hearing loss found in premature infants.3

Over a decade's worth of research shows that common sounds, such as closing the incubator porthole, may reach levels from 100 dB up to 135 dB -- the equivalent to that of exposing a neonate's sensitive ears and immature nervous system to the noise level of a rock concert.2,3,4

The American Academy of Pediatrics, Committee on Environmental Health, recommends a maximum safe noise level of 45 dB in the NICU.2 Yet, clinical studies show that the average sound levels in the NICU range anywhere from 70 to 80 dB.5 More importantly, researchers have documented that reduced noise levels in the NICU:

  • Positively impact sleep state, both increasing the amount of time spent in quiet sleep state and lengthening the periods of time spent asleep.
  • Positively impact oxygenation.2,3

An important part of optimizing NICU care for premature newborns is the reduction of high-intensity noise exposure to babies. The table below provides an overview of different noise levels and their effects on the neonate.

 

Noise Levels and Their Effects2

Quality Peak Intensity, dBA Example Equivalent Inside Incubator Effect
Just Audible 10 Heartbeat    
Very Quiet 20 - 30 Whisper   <35 dBA desired for sleep
Quiet 40 Average home    
  50 Light traffic Background <50 dBA desired for work
Moderately Loud 60 Normal Conversation Motor on and off  
  70 Vacuum Cleaner Bubbling in ventilator tubing Annoyance
Loud 80 Heavy traffic or telephone ringing Tapping incubator with fingers  
  90 Pneumatic drill Closing the metal cabinet doors under the incubator Hearing loss with persistent exposure
Very Loud 100 Power mower Closing solid plastic porthole  
Uncomfortably Loud 120 Boom box in car Dropping the head of the mattress Pain and distress
  140 Jet plane 30 meters overhead    

 

MiniMuffs® Neonatal Noise Attenuators provide a comfortable, easy-to-use solution for decreasing the noise levels for babies in the NICU. They are specifically designed for premature infants and decrease noise levels to the baby by at least 7dB, representing a reduction in sound pressure of more than 50%.6

 

1 Strauch C, Brandt S, Edwards-Beckett J. Implementation of a quiet hour: effect on noise levels and infant sleep states. Neonatal Network. 1993;12(2):31-35 
2 American Academy of Pediatrics, Committee on Environmental Health. Noise: a hazard for the fetus and newborn. Pediatrics. 1997;100(4):724-727 
3 Zahr LK, de Traversay J. Premature infant responses to noise reduction by earmuffs: effects on behavioral and physiologic measures. J Perinatol. 1995;15(6):448-455 
4 Northern JL, Downs MP. Hearing in Children. 4th ed. Baltimore, MD: Williams & Wilkins; 1991:17 
5 Gottfried A, Hodgman J. How intensive is newborn intensive care? An environmental analysis. Pediatrics. 1984;74(2):292-294 
6 Environmental Protection Agency (EPA) Noise Reduction Rating of 7dB. A decrease of 6dB reduces sound pressure level by 50%