The influence of hemorrhagic shock on ocular microcirculation by obtained by laser speckle flowgraphy in a white rabbit model.

Abstract

To clarify the continuous changes in the retinal vessels' and choroid's microcirculation during hemorrhagic shock and resuscitation in a rabbit model. Hemorrhagic shock by the removal of blood (30mL) and resuscitation by a blood-return technique was induced in anesthetized male New Zealand White rabbits (n = 10). We evaluated the retinal vessel blood flow (relative flow volume: RFV) and choroidal blood flow (mean blur rate in the choroid area: MBR-CH) by laser speckle flowgraphy (LSFG), with simultaneous measurements of systemic hemodynamics and laboratory parameters. RFV and MBR-CH showed significant decreases immediately after the initiation of blood removal and recovered by blood return. The lactate concentration tended to increase from baseline by the blood-removal operation, and it was significantly higher at the end of observation period. The %RFV and %MBR-CH each showed a significant positive correlation with mean arterial blood pressure, cardiac output, carotid blood flow, and central venous pressure. %RFV showed a significant positive correlation with %central venous oxygen saturation and negatively correlated with %lactate. The %hemoglobin did not show a significant correlation with %RFV or %MBR-CH. This rabbit hemorrhagic shock model confirmed that ocular microcirculation measurements by LSFG feasibly reflect variations in systemic hemodynamics during hemorrhagic shock and recovery.