Abstract 114: Use Of Medical Hyperspectral Imaging in the Evaluation of Blunt Chest Trauma and Hemorrhagic Shock in a Porcine Model
INTRODUCTION: Hyperspectral Technology cutaneous Oxygenation Monitoring (HTcOM) provides scans that quantify oxyhemoglobin (HT-Oxy) and deoxyhemoglobin (HT-Deoxy) on a pixel by pixel basis. In monitoring mode, a series of sequential scans show oxygen delivery to the tissue and oxygen extraction by the tissue of interest. In this study, we tested the feasibility of using HTcOM to monitor tissue oxygenation changes during blunt chest trauma and hemorrhage.
METHODS: 16 female Yorkshire pigs (∼35kg, 10 bleed, 6 controls) are undergoing a combined blunt chest trauma & hemorrhage protocol implementing blunt right chest trauma with a modified captive-bolt humane stunner under anesthesia. Severity of pulmonary contusion is documented by arterial & venous blood gases & CT scans at 0, 15, 30, 60, & 120 min. Injury is followed 120 min later by constant-rate, fixed-volume hemorrhage of 40 ml/kg in 2 stages, with 20 min between stages. Hyperspectral imaging of the anterior lower extremities (near infrared system) and the lower abdomen (visible light system) is continuously performed.
RESULTS: To date, 3 pigs have been studied. With chest trauma HT-Deoxy levels increased on average by 50% (range 14–112). Following 1st bleed, changes to HT-Oxy & HT-Deoxy were small while following 2nd bleed, HT-Oxy dropped 15% (range 11–20) & HT-Deoxy increased 4% (range 2–7). Using ANOVA, with HT-Oxy & HT-Deoxy as the outcomes & measurements made between 5 min before & 5 min after the event (injury, bleed 1, bleed 2, & death) as the predictive factors, changes in the 2 outcomes associated with the events (p<0.001). Changes in HT-Oxy correlated with systolic BP for event periods (r = 0.47 to 0.97). HT-Oxy & HT-Deoxy also correlated with blood lactate values [r = −0.64 to −0.89 for HT-Oxy, 0.36 to 0.66 for HT-Deoxy], PvO2 [r = 0.62 to 0.88 for HT-Oxy, −0.78 to −0.81 for HT-Deoxy].
CONCLUSIONS: Quantitative measures of HT-Oxy & HT-Deoxy were extracted from HTcOM data & used to determine skin microvascular changes as a local manifestation of systemic hemodynamics in injured swine. Consistent trends of HTcOM responses were noted and found to be different with injury vs hemorrhage. HTcOM provides information that may be useful in the clinic & in the field to aid in the assessment of trauma patients.