Quantification of impulse experienced by neonates during inter- and intra-hospital transport measured by biophysical accelerometery

Background: Transport of premature infants incurs transfer- related morbidity, including intraventricular hemorrhage, a contributing factor to cerebral palsy. The force transmitted to the neonate during transport as a consequence of motion may be implicated in the increased morbidity in this population. Morbidity may occur via direct concussive force to a vulnerable germinal matrix, induction of an inflammatory reaction, or via transient desaturation via extubation. This transmitted force, measured as accelerations per unit time (impulse), is not well characterized. Any modification of a neonatal transporter which increases the time for a neonate in motion to come to rest may decrease the impulse experienced by the infant. Objective: The objective of the study was to quantify the magnitude of impulse experienced by neonates during inter- and intra- hospital transport using a novel biophysical model and determine whether a specialized air-foam mattress can reduce the transmitted impulse on the neonate. Methods: Five roundtrip trials were conducted for a transported neonate using a standard medical ambulance and transport isolette outfitted with an air-foam mattress. During the trials, measurements were made per second in the X (front-to-back), Y (side-to-side), and Z (up-and-down) planes using a computerized accelerometer attached to a neonatal resuscitation mannequin. Results were integrated over the trial time in each dimension to yield a measure of impulse (acceleration-per-unittime). Total impulse for the trial was calculated. A second design included five trials from the delivery room to the NICU utilizing four different transport configurations with a standard neonatal isolette outfitted with a gel pillow, air-foam mattress, and air-foam mattress with gel pillow. Results: Mean impulse for the transport model was statistically greater than at rest. In the X and Z dimensions, the mean impulse was significantly lower using the air-foam mattress. The impulse of the Z dimension with the air-foam mattress did not differ from that experienced by the experimental model at rest. For the intra-hospital trial, all experimental set-ups produced significantly less cumulative impulse than the standard isolette, though in each specific dimension, no significant differences were noted. For cumulative impulse, no significant differences between any of the three experimental designs were observed. A trend toward decreased transport time was seen with the addition of the air-foam mattress and gel pillow. Conclusions: The mechanical trauma induced by transport can be measured and quantified using this system. Neonates transported with the air-foam mattress experienced less impulse in the front-to-back and up-anddown dimensions. For transports between the delivery room and NICU, neonates transported using the air-foam mattress and gel pillow experienced significantly less total impulse.