Abstract
Background
Health-care practitioners should be aware of how their equip-ment and practices can increase the patient's risk for noise-induced hearing loss. PURPOSE: We conducted this study to determine the type of noise pro-duced by humidifiers and nebulizers used with hoods in the neonatal inten-sive care unit (NICU). We performed octave waveband analysis to determine sound intensities and frequencies because degree of hearing loss from noise exposure is related to the intensity of sound, frequency of sound, and dura-tion of exposure.
Methods
We studied 4 simple humidifiers, 3 heated hu-midifiers, and 4 nebulizers. Sound levels were measured at various frequencies, flows, and water levels using Peace and Shiley oxygen hoods.
Results
The findings show that sound levels were significantly louder (p < 0.001) for neb-ulizers compared to humidifiers. Aquapak nebulizers pose the greatest risk for hearing loss because they produce sound at the highest frequencies and volume. The peak sound levels of humidifiers not only were significantly lower but also occurred at the lowest sound frequencies, which are the least dam-aging to hearing. Sound levels were generally higher across sound frequen-cies at higher flows and with the Peace Hood.
Conclusion
We conclude that heated humidifiers produce lowest sound intensities at the lowest sound frequencies and, consequently, are most appropriate for use in the NICU.
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