Elevated Sound Levels within a Busy NICU

Purpose: Elevated sound levels in the NICU may contribute to undesirable physiologic and behavioral effects in preterm infants. This study describes sound levels in a busy NICU in the southeastern U.S. and compares the findings with recommended NICU noise level standards.

Design: NICU sound levels were recorded continuously at nine different locations within the NICU. Hourly measurements of loudness equivalent (Leq) sound level, sound level exceeded 10 percent of the time (L₁₀), and maximum sound level (Lmax) were determined.

Sample: Sound levels were sampled from nine different locations within the NICU.

Main Outcome Variable: Sound levels are described using the hourly, A-weighted Leq, L₁₀, and Lmax.

Results: The overall average hourly Leq (M = 60.44 dB, range = 55–68 dB), L₁₀ (M = 59.26 dB, range = 55–66 dB), and Lmax (M = 78.39, range = 69–93 dB) were often above the recommended sound levels (hourly Leq <50 dB, L10 <55 dB, and 1-second Lmax <70 dB). In addition, certain times of day, such as 6–7 AM and 10 AM–12 noon, were noisier than other times of day.