mechanical vibration in neonatal transport: a randomized study of different mattresses1

Objective: to verify the most effective hypothesis of gel mattresses in reducing mechanical vibration in the transport of newborns, we conducted a randomized grouping study of four mattress combinations (
No, foam, gel, gel on foam)
Mannequin and ambulance driving using a fixed route (city, highway).
Study Design: evaluate mechanical vibration by measuring the vertical acceleration of two positions: 2000-
General human model and transportation incubation base.
From the time history of these acceleration,RMS)
The values and power spectral density functions are calculated.
The effect of the mattress on vibration transmission is determined based on the ratio of RMS values in both positions.
RMS ratio less than 1.
0 indicates attenuation, while the ratio is> 1.
0 indicates that the vibration is aggravated.
From the power spectral density function, the inherent frequency of each mattress combination of the system relative to the inherent frequency of the ambulance is determined.
To determine the effect of the weight of the human model on vibration, 300-gm mannequin.
Results: all observed RMS ratios were> 1.
In the absence of a gel mattress, the highest rate observed on the city route.
Gel mattresses used alone or in conjunction with foam mattresses, compared to foam mattresses or foam-free mattresses, deviate the inherent frequency of the system from the inherent frequency of ambulances, large Vibration Amplification is avoided.
The reduction in the weight of the mannequin causes the gel mattress to be less effective in terms of attenuation vibration.
Conclusion: gel mattresses used alone or in conjunction with foam mattresses can cause minimal vibration, but the vibration in ambulance transport will not be weakened by any mattress combination.
When transporting very low birth weight freshmen, the hazard of vibration may be particularly relevant.
These findings indicate the need to study and design more effective devices that can reduce vibration stress.