Sound levels and its effect on physiology of low birth weight newborns in a special care newborn unit — a prospective observational study

Abstract

Abstract Background From quiet environment in uterus, neonates in special care newborn units (SCNU) get exposed to a stressful technology-driven environment. Noise level in neonatal intensive care units (NICU) depends on social and psychological realm of people working there. In NICU, an hourly Leq (median equivalent continuous sound level) of sound should be 45 dB, Lmax, 60 dB, and L10 not exceeding 50 dB (AAP, 2007). Noise level in SCNUs of northeast India has not been studied. Aim Create awareness among health workers (HW) regarding noise. Objective To study (a) noise level in special care newborn unit and (b) its effect on neonatal physiology. Methodology A prospective observational study was conducted in a teaching hospital in northeast India for 1 month. After IEC approval, ambient sound levels in intensive care unit (ICU) (levels 2 & 3) and kangaroo mother care (KMC) area were measured using inVH by Bosch Engineering Solution (android app) in 3 shifts. Forty hemodynamically stable quiet low birth weight neonates (level 2: 16, level 3: 14, KMC: 10) were evaluated for heart rate and respiratory rate at same time. Acutely sick neonates were excluded. Statistical analysis was done using SPSS. Results Average sound at 10 am, 5 pm, and 11 pm in level 2 was 70.2 (+ 3.78) dB, 71.9 (+ 4.21) dB, and 54.6 (+ 5.38) dB; in level 3: 66.4 (+ 3.71) dB, 64.9 (+ 3.88) dB, and 63.5 (+ 2.52) dB; and KMC: 55.06 (+ 5), 54.66 (+ 5.38), and 47.7 (+ 5.1) dB (p = 0.0052). Of included neonates, mean birthweight in intensive vs KMC area was 1.378 (+ 0.017) vs 1.337 (+ 0.02) kg (p = 0.1) and gestational age 35.45 (+ 0.25) weeks and 34.8 (+ 0.91) weeks (p = 0.2). The mean neonatal heart rate and respiratory rates in level 2 were 154/min and 44 cycles/min, level 3: 148/min and 47 cycles/min; and KMC: 124/min and 40 cycles/min. Conclusion Significant noise pollution is detected in levels 2 and 3 neonatal intensive care units and minimal in kangaroo mother care area. Raised neonatal heart rates and respiratory rates in intensive care units with respect to KMC area may be related to noise. The social and psychological realm of healthcare workers and caregivers needs urgent improvement so as to reduce ambient noise pollution in special care newborn units.