Affiliations: [a] Biophysics division, Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| [b]
Department of Critical Care, Kings College Hospital, Denmark Hill, London, UK
Correspondence:
[*]
Corresponding author: Dr. Sam Hutchings, Department of Critical Care, Kings College Hospital, Denmark Hill, LondonSE5 9RS, UK. Tel.: +2032999000; E-mail: [email protected].
Abstract: We report a new microcirculatory assessment device, the Braedius Cytocam, an Incident Dark Field (IDF) video microscope, and compare it with a precursor device utilising side stream dark field (SDF) imaging. METHODS:Time matched measurements were made with both devices from the sublingual microcirculation of pigs subjected to traumatic injury and hemorrhagic shock at baseline and during a shock phase. Images were analysed for vessel density, microcirculatory flow and image quality. RESULTS:There were no differences in density or flow data recorded from the two devices at baseline [TVD IDF 14.2 ± 2.4/TVD SDF 13.2 ± 2.0, p 0.17] [MFI IDF 3 (2.8–3.0)/MFI SDF 3 (2.9–3.0), p 0.36] or during the shock state [TVD IDF 11.64 ± 3.3/TVD SDF 11.4 ± 4.0 p = 0.98] [MFI IDF 1.9 (0.6–2.7)/MFI SDF 1.7 (0.3–2.6) p 0.55]. Bland and Altman analysis showed no evidence of significant bias. Vessel contrast was significantly better with the IDF device for both capillaries [17.1 ± 3.9 (IDF) v 3.4 ± 3.6 (SDF), p = 0.0006] and venules [36.1 ± 11.4 (IDF) v 26.4 ± 7.1 (SDF) p 0.014] CONCLUSION:The Braedius Cytocam showed comparable vessel detection to a precursor device during both baseline and low flow (shock) states.
Keywords: Microcirculation, sidestream dark field imaging, incident dark field imaging, haemorrhagic shock
