[Noise exposure in level III NICU environment in Beijing region and effects of intervention measures]

To study the source of noise in level III NICU in Beijing region, evaluate preliminary intervention measures, and improve the NICU environment by reducing the noise.

Noise measurements were performed in level III NICU of three hospitals (A, B and C) in Beijing region by dosimeter (B&K 2231, Denmark), during loud hours and quiet hours. In addition, the loud hours were divided into shift time, nursing time and operating time. "Quiet hours" represents the intervals among shift, nursing and operating time. The noise inside/outside incubator was recorded, measures to reduce the noise, including putting plastic foam in incubator, covering sheet and blanket outside incubator were taken, and an educational program was implemented for the staff to decrease noise in the NICU environment.

Among the three hospitals, the average noise of was (62.60 +/- 2.33) dB during the loud time, and (55.80 +/- 2.61) dB during the quiet time, with a difference of 7 dB (P < 0.05). There was a significant decrease of 2.7 - 3.3 dB during shift time with the averages of A hospital (62.3 +/- 1.5) dB, B hospital (65.10 +/- 2.44) dB and C hospital (61.80 +/- 1.91) dB (F = 9.57, P < 0.05 and P < 0.01), separately. There was a significant decrease of 3 dB during nursing time with the averages of A hospital (62.0 +/- 2.4) dB, B hospital (64.90 +/- 1.06) dB (P < 0.01), respectively, and 2.5 - 3.0 dB during treatment time with the averages of A hospital (60.7 +/- 2.2) dB, B hospital (63.30 +/- 1.19) dB (P < 0.05), separately. After educating the staff in hospital A, there was a significant decrease of 4.7 dB from (61.70 +/- 2.12) dB to (56.90 +/- 2.49) dB in the loud time (P < 0.01), no significant difference during quiet time from (55.0 +/- 1.7) dB to (53.90 +/- 0.88) dB (P > 0.05). There was a significant decrease of 10 dB (P < 0.01) between the averages of inside of incubator (58.60 +/- 3.43) dB and outside of incubator (67.10 +/- 1.87) dB; After installing foam material inside incubator with the average of (56.20 +/- 1.83) dB, there was a significant decrease of 2.8 dB (P < 0.01); covering sheet (in front and back) with the averages of (57.00 +/- 1.47) dB and (55.3 +/- 1.3) dB, respectively, and single or double blanket outside incubator (in the front and the back) noise value (54.50 +/- 1.33) dB, (54.10 +/- 1.15) dB and (54.70 +/- 0.63) dB and (54.10 +/- 1.14) dB, separately, there was a decrease of 1 - 4 dB (P < 0.05 and P < 0.01).

The noise in level III NICU in Beijing region is much higher than that allowed by regulations in Europe and the USA. Staff behavior and the acoustical characteristics of the facility determine the level of noise; herein to staff behavior is the main cause. The level of noise can be lowered considerably by simply making the staff aware of the problem. At the same time, covering incubator and installing plastic foam material also significantly decreased the noise, the methods are simple, feasible and should be applied constantly.