The Effect of Speed and Road Type on Sound Pressure Level During Neonatal Patient Transport

Abstract

<div class="section abstract"><div class="htmlview paragraph">Neonatal Infants (neonates) requiring a higher level of care often require transportation via road ambulance to neonatal intensive care units. The trip in the ambulance exposes these infants to potentially harmful noise and vibration. The aim of this study was to categorize the sound level in and around the Neonatal Patient Transport System (NPTS) during transport in ambulances at different speeds and different road types. Data collection was performed in Ottawa, Canada. The road types categorized in the study include arterial roads, collector/major collector roads, local roads, lanes and highways. Additionally, discrete events including rail-road crossings, speed humps and potholes were also categorized. For comparison, the sound levels in the ambulance cabin and near the driver were also taken and analyzed. By categorizing the effects these factors have on the sound level experienced by the neonate, better route planning and sound mitigation strategies can be employed. Using the sound levels in the decibel A scale (dBA) for each road test, trendlines could be created showing the variation in sound levels with speed and road type. It is observed that the average sound level experienced by the neonate in the NPTS (IsoletteMic) when stationary is approximately 56 dBA. A steady increase in sound level corresponding to an increase in speed was observed. However, there was no substantial variation in the sound level experienced on different road types at similar speeds. The results suggest that noise exposure increases significantly with vehicle speed, is largely independent of road type, and contains elements that are representative of the Children’s Hospital of Eastern Ontario (CHEO) patient transfers. Building off that knowledge, it is be suggested that improved noise shielding and route planning should be employed to improve neonates’ safety during transport.</div></div>