Physiological Impact of Environmental Stressors During Neonatal Transport: A Systematic Review of Clinical and Biophysical Outcomes.

Neonatal inter-hospital transport exposes critically ill and premature infants to a range of environmental stressors, including mechanical vibration, excessive noise, and temperature dysregulation, which may compound underlying pathophysiology and contribute to adverse outcomes. Despite growing recognition of this concern, the extent and clinical significance of these exposures remain incompletely characterised. The objective of this study is to systematically review the available literature on the physiological impact of environmental stressors during neonatal transport and synthesise evidence on biophysical exposures and clinical outcomes. A systematic search of MEDLINE, Embase, CINAHL, and the Cochrane Library was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. The search covered the period from 1 January 2016 to 31 December 2025. Studies reporting environmental stressor measurements (vibration, noise, temperature, acceleration) and/or associated physiological outcomes in neonates or paediatric patients during inter-hospital transport were eligible. Risk of bias was assessed using the Newcastle-Ottawa Scale, the Joanna Briggs Institute critical appraisal checklist for quasi-experimental studies, and the AXIS tool, as appropriate. The review was not prospectively registered. Ten studies, published between 2016 and 2025, met the inclusion criteria. Whole-body vibration frequently approached or exceeded the European Union occupational action value (0.5 m/s²), reaching up to 70% of this value in individual transfers, although these adult-derived thresholds may not reflect true neonatal risk. Noise consistently surpassed the American Academy of Pediatrics-recommended ceiling of 45 dB(A). Hypothermia affected 8-40% of transported neonates, with the highest rates in very low birthweight infants under arctic conditions. Behavioural distress measures were significantly elevated throughout transfer procedures. Cerebral regional oxygen saturation drops of ≥20% from baseline occurred in 40-55% of transported patients in a single pilot study. Four studies were rated as low overall risk of bias, four as moderate, and two as high. Neonates undergoing inter-hospital transport are routinely exposed to environmental stressors at levels exceeding established adult safety thresholds, with consistent evidence of associated physiological and neurological risk. Several exposures, including vibration and thermal dysregulation, are potentially modifiable through routing optimisation, equipment design, and operational protocols. Neonatal-specific safety standards are urgently needed.