Vibration Exposure During Neonatal Patient Transport by Ground and Air Ambulance

Neonatal transport is often necessary when newborn patients require specialized medical care. In Ontario, Canada, a standardized Neonatal Patient Transport System (NPTS) is used to ensure consistency and interoperability across healthcare facilities. Whether transport is conducted via ground ambulance, fixed-wing, or rotary-wing air ambulances, the transport system and patient are subjected to unique, and often high, levels of vibration. Vibration is transmitted throughout the NPTS and interface systems such that the patients may experience a different ride quality than transport team members, pilots, or drivers. We have investigated the vibration amplitudes and spectra from 1-150 Hz at multiple locations (floor, NPTS, pilot/driver floor, and pilot/driver seat) within four different vehicles used for neonatal transportation in Ontario (one ground ambulance, one helicopter, and two fixed-wing aircraft). Kinematics were used to evaluate locations where sensors were not present during data collection. A low-frequency range of 1-20 Hz was used for comparison of measured and predicted results, to reduce noise in kinematic acceleration evaluation while focusing on the range of human body resonance. The largest amplitude vibrations were measured in the vertical direction in all vehicles, with the ground ambulance acceleration being greatest. Amplification of ground vehicle motion to the patient location was present across much of frequency range of interest, although the highest transmissibility occurred in the helicopter vertical direction at 10 Hz. The vibration in the air ambulances was heavily dominated by the rotor or propeller frequency, while in the ground ambulance it was more significant at low frequencies related to vehicle suspension. Differing response spectra suggest efforts to improve ride quality for patients may need to be tailored to the vehicle type, in order to prevent patient exposure to high amplitude vibration.