Mechanical vibration and sound levels experienced in neonatal transport.

Exposure of neonates to sound and to mechanical vibration was measured while transferring the neonates to a regional referral unit by ambulance and by rotary wing and fixed wing aircraft. Recordings were made during different phases of each type of transportation and were analyzed later. In the nursery, sound levels ranged from 72 to 74 dBA (A-weighted decibel level) (77 to 81 dB), while in transit, levels were higher at 78 to 99 dBA (90 to 110 dB), depending on the means of transport. Vibration was measured in the horizontal and vertical axes relative to the neonate in different frequency ranges. The vibration acceleration magnitude ranged from 0.4 m/sq s to 5.6 m/sq s, depending on the axis and type of transport; the maximum obtained was in rotary wing transport. When compared with adult tolerance levels, both sound and vibration exposure of the neonate are high and potentially hazardous. Further evaluation of vibration stress and means of attenuating sound and vibration in transport infant incubators is desirable to enhance the safety of transported infants.