Neonatal head and torso vibration exposure during inter-hospital transfer

Blaxter, Laurence; Yeo, Mildred; McNally, Donal; Crowe, John; Henry, Caroline; Hill, Sarah; Mansfield, Neil; Leslie, Andrew; Sharkey, Don

Abstract

© Institution of Mechanical Engineers. Inter-hospital transport of premature infants is increasingly common, given the centralisation of neonatal intensive care. However, it is known to be associated with anomalously increased morbidity, most notably brain injury, and with increased mortality from multifactorial causes. Surprisingly, there have been relatively few previous studies investigating the levels of mechanical shock and vibration hazard present during this vehicular transport pathway. Using a custom inertial datalogger, and analysis software, we quantify vibration and linear head acceleration. Mounting multiple inertial sensing units on the forehead and torso of neonatal patients and a preterm manikin, and on the chassis of transport incubators over the duration of inter-site transfers, we find that the resonant frequency of the mattress and harness system currently used to secure neonates inside incubators is ∼ 9 H z. This couples to vehicle chassis vibration, increasing vibration exposure to the neonate. The vibration exposure per journey (A(8) using the ISO 2631 standard) was at least 20% of the action point value of current European Union regulations over all 12 neonatal transports studied, reaching 70% in two cases. Direct injury risk from linear head acceleration (HIC15) was negligible. Although the overall hazard was similar, vibration isolation differed substantially between sponge and air mattresses, with a manikin. Using a Global Positioning System datalogger alongside inertial sensors, vibration increased with vehicle speed only above 60 km/h. These preliminary findings suggest there is scope to engineer better systems for transferring sick infants, thus potentially improving their outcomes.

Citation

Blaxter, L., Yeo, M., McNally, D., Crowe, J., Henry, C., Hill, S., Mansfield, N., Leslie, A., & Sharkey, D. (2017). Neonatal head and torso vibration exposure during inter-hospital transfer. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 231(2), 99-113. https://doi.org/10.1177/0954411916680235

• Journal Article Type: Article
• Acceptance Date: Nov 13, 2016
• Online Publication Date: Jan 5, 2017
• Publication Date: Feb 1, 2017
• Deposit Date: Jan 16, 2017
• Publicly Available Date: Jan 16, 2017
• Journal: Institution of Mechanical Engineers. Proceedings. Part H: Journal of Engineering in Medicine
• Print ISSN: 0954-4119
• Electronic ISSN: 2041-3033
• Publisher: SAGE Publications
• Peer Reviewed: Peer Reviewed
• Volume: 231
• Issue: 2
• Pages: 99-113
• DOI: https://doi.org/10.1177/0954411916680235
• Keywords: Vibration hazard, shock hazard, linear head acceleration, neonatal, brain injury, monitoring, intraventricular haemorrhage
• Public URL: https://nottingham-repository.worktribe.com/output/841758
• Publisher URL: http://journals.sagepub.com/doi/10.1177/0954411916680235