Measurement of sound levels in a neonatal intensive care unit of a tertiary care hospital, Karachi, Pakistan

Background: High sound levels in the neonatal intensive care unit (NICU) can alter preterm newborn hemodynamics and cause long-term neuro-developmental delays and hearing loss. The study aims to collate data on sound levels in a level IV NICU of a tertiary care hospital, identify the factors associated with them, and compare them with the international standards set by the World Health Organization (WHO), Environmental Protection Agency (EPA), and American Academy of Pediatrics (AAP).Methods: We carried out a cross-sectional study in NICU from 8th April 2019 to 30th June 2019. Sound levels were recorded for 480 h, using a portable sound meter, the Larson Davis 824. We captured sound levels on alternate days, during different shifts and shift changes and in open pods and single isolation rooms within the NICU. Additionally, we documented the total census, acuity of care, number of staff, number of procedures, and number of items of equipment used. The data was analyzed using t-test, ANOVA, and logistic regression.Results: The average sound level (Leq) and the maximum level (Lmax) recorded were 60.66 ± 2.99 dBA and 80.19 ± 2.63 dBA, respectively, which exceeds international recommendations. The sound level gradually decreased from morning to night hours. The major increase in sound was observed during nursing shift change. Similarly, a significant increase in sound was observed in open bays compared to isolation rooms. However, no difference in sound levels was recorded during weekdays and weekends. The number of healthcare professionals and the number of procedures performed were strongly associated with an increased noise level.Conclusion: Sound levels in NICU were beyond the safety range and international recommendations. We observed a significant sound increment during morning hours and at the time of nursing shift change. High sound levels were associated with increased number of healthcare workers and bedside procedures in NICU