Critical Care Instructor Baylor College of Medicine Houston, Texas, United States
Abstract:
Introduction: Periods of excess noise are common in intensive care units and have been linked to increased markers of stress and altered brain development in neonates. Newborns with congenital heart disease often live in a tenuous physiologic state and noxious stimuli are frequently associated with adverse hemodynamic events. Therefore, it is prudent to describe the soundscape within a critical care environment, while exploring ways to reduce unwanted noise. The purpose of this investigation is to determine temporal patterns of sound in a specialized neonatal cardiac intensive care unit.
Methods: This was an observational study of the acoustic environment of an intensive care unit in a quaternary pediatric hospital to which provides care to neonates with cardiac diseases. Noise levels were continuously recorded using USB microphones (Samson Go Mic) strategically installed approximately three feet from the head of the patient bed. Sound pressure data measured in micropascals (uPa) were collected over a one-month period from June-July 2022. Time-stamped measurements were automatically uploaded to the Sickbay Clinical Platform (Medical Informatics Corp., Houston, TX). For the descriptive analysis, data were stratified by hour of the day.
Results: A total of 4,637,908 measurements were analyzed. The range of sound pressures measured were 69 to 103 uPa, with a mean of 76.9 uPa. When data were stratified by hour of the day, median noise level was similar ranging from 76-77 uPa. The 25th percentile for sound pressure, which we defined as the ambient soundscape, was 76 uPa at each hour. The 95th and 97.5th percentiles, respectively, were used to delineate moderately noisy and highly noisy atmospheres. The quietest hours were between 1:00 and 5:00 am. Subsequently, there was a notable upward trend in moderate and highly noisy events after 7:00am, with peak noisiness noted between the hours of 1:00 and 6:00 p.m. Only after the 10:00 p.m. hours did noisiness improve.
Conclusion: In our neonatal cardiac intensive care unit, there are notable temporal variations in the sound environment, with the noisiest times being late morning through late afternoon. This corresponds with times when intensive care rounds are conducted, post-operative volume is high, and when most patient interventions are performed. Further investigation will analyze the relationship between noisy events and physiologic changes in these vulnerable patients.
