Noise Levels of Invasive and Non Invasive Respiratory Support used in Neonatal Intensive Care Unit of Northern India: A Cross-sectional Study

Introduction: The average noise level exposure inside Neonatal Intensive Care Unit (NICU) is more than the recommended guidelines. The source of noise exposure inside NICU is multifactorial. There is need of studies to assess the noise levels of respiratory equipment used inside the NICU. Aim: To assess the noise levels of invasive versus non invasive and respiratory support in preterm neonates admitted to NICU. Materials and Methods: This cross-sectional descriptive study was done in NICU of a tertiary health care center of Sanjay Gandhi Postgraduate Institute, Lucknow, Uttar Pradesh, India over one year duration from December 2019 to December 2020. A sample of 85 eligible neonates without major congenital anomalies (26- 36+6 weeks gestation) was enroled in this study after obtaining informed consent from parents. The noise levels of Heated Humidified High Flow Nasal Cannula (HHHFNC), Continuous Positive Airway Pressure (CPAP), conventional ventilation and High-Frequency Ventilation (HFV) were measured using a sound level meter for a period of first 24 hours of life. The median sound level from non invasive ventilation is compared with invasive ventilation. The continuous variables were expressed as median with range, while categorical data were expressed as frequencies and percentages. Results: A total of 85 neonates were enroled majority of them were born in 32-34 weeks of gestation and were with birth weight of 1501-2500 grams. The sound level exposure of HHHFNC support was 56.1 dB (52.6-60 dB) from warmer and 47.3 dB (44.6-50.8 dB) from the incubator. The median sound level exposure per hour of bubble CPAP was 59 dB (55.2-61.9 dB) with warmer and 51.4 dB (47-55 dB) with incubator. The median sound level exposure per hour of the conventional ventilator was 60 dB (57.4-63.9 dB) with warmer and 53 dB (50.2-56.1 dB) with incubator. The median sound level exposure per hour of high-frequency ventilator was 69.1 dB (66.3-71.8 dB) with warmer and 67.3 dB (66.2-68.9 dB) with incubator. Conclusion: Non invasive ventilation (HHHFNC and bubble CPAP) was less noisy than invasive ventilation. The lowest measured noise exposure was higher than the American Academy of Paediatrics (AAP) recommendation of 45 dB, even after isolation with physical barrier.