Introduction Skin perfusion varies in response to changes in the circulatory status. Blood flow to skin is reduced during haemodynamic collapse secondary to peripheral vasoconstriction, whereas increased skin perfusion is frequently observed when haemodynamics improve with resuscitation. These changes in perfusion may be monitored using non-contact image-based methods. Previous camera-derived physiological measurements have focused on accurate vital signs monitoring and extraction of physiological signals from environmental noise. One of the biggest challenges of camera-derived monitoring is artefacts from motion, which limits our understanding of what parameters may be derived from skin. In this study, we use phenylephrine and glyceryl trinitrate (GTN) to cause vasoconstriction and vasodilation in stationary healthy volunteers to describe directional changes in skin perfusion pattern.
Methods and analysis We aim to recruit 30 healthy volunteers who will undergo protocolised infusions of phenylephrine and GTN, followed by the monitored and timed release of a thigh tourniquet. The experimental timeline will be identical for all participants. Measurements of traditionally used haemodynamic markers (heart rate, blood pressure and stroke volume) and camera-derived measurements will be taken concurrently throughout the experimental period. The parameters of interest from the image data are skin colour and pattern, skin surface temperature, pulsatile signal detected at the skin surface and skin perfusion index.
Ethics and dissemination This study was reviewed and approved by the Oxford University Research and Ethics Committee and Clinical Trials and Research Governance teams (R63796/RE001). The results of this study will be presented at scientific conferences and published in peer-reviewed journals.
Trial registration number ISRCTN10417167.
- clinical physiology
- clinical pharmacology
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Contributors MH conceived the study with guidance from PJW, DY, LT, MV and JJ. MH, CA, MV, JJ, EF and SD will conduct screening and data collection. MH and AM planned the statistical analysis. Analysis will be performed by MH, MV, JJ, EF and SD. MH prepared the first draft of this manuscript. All authors critiqued and edited the manuscript for intellectual content.
Funding This work was supported by NIHR Oxford Biomedical Research Centre (BRC) under Technology & Digital Health theme. NIHR Oxford BRC advocates open access. MH, CA and PJW are funded by NIHR Oxford BRC. The work of JJ was supported by the RCUK Digital Economy Programme, grant number EP/G036861/1 (Oxford Centre for Doctoral Training in Healthcare Innovation). JJ also acknowledges Fundacao para a Ciencia e Tecnologia, Portugal, doctoral grant SFRH/BD/85158/2012. MV was supported by the Oxford Centre of Excellence in Medical Engineering funded by the Wellcome Trust and EPSRC under grant number WT88877/Z/09/Z. Trial sponsor: University of Oxford, Oxford, UK.
Disclaimer The funders have had no role in the study protocol design or the preparation of this manuscript, and will have no role in the collection, management, analysis and interpretation of the data, or the writing of the final report.
Competing interests PJW is Chief Medical Officer for Sensyne Health and holds share options in the company. His organisation has received research funding from Sensyne Health not associated with this work. LT is a non-executive Director of Sensyne Health and holds share options in the company. LT is a non-executive Director of Oxehealth and holds shares in the company.
Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the ‘Methods’ section for further details.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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