Tissue Oxygenation Monitoring using Resonance Raman Spectroscopy during Hemorrhage
ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX
Pagination or Media Count:
BACKGROUND The ability to monitor the patient of hemorrhage noninvasively remains a challenge. We examined the ability of resonance Raman spectroscopy to monitor tissue hemoglobin oxygenation RRS-StO2 during hemorrhage and compared its performance with conventional invasive mixed venous SmvO2 and central venous ScvO2 hemoglobin oxygen saturation aswell as with near-infrared spectroscopy tissue hemoglobin oxygenation NIRS-StO2. METHODS Five male swine were anesthetized and instrumented followed by hemorrhage at a rate of 30 mLmin for 60 minutes. RRS-StO2 was continuously measured from the buccal mucosa, and NIRS-StO2 was continuously measured from the forelimb. Paired interval measures of SmvO2, ScvO2, and lactate were made. Pearson correlation was used to quantify the degree to which any two variables are related. Receiver operating characteristic ROC area under the curve values were used for pooled data for RRS-StO2, NIRS-StO2, SmvO2, and ScvO2 to compare performance in the ability of tissue oxygenation methods to predict the presence of an elevated arterial blood lactate level. RESULTS Sequential RRS-StO2 changes tracked changes in SmvO2 r 0.917 95 confidence interval CI, 0.867 0.949 and ScvO2 r 0.901 95 CI, 0.828 0.944 during hemorrhage, while NIRS-StO2 failed to do so for SmvO2 r 0.283 95 CI, 0.04919 0.4984 and ScvO2 r 0.142 95 CI, 0.151 to 0.412. ROC curve performance of oxygenation measured to indicate lactate less than or greater than 3 mM yielded the following ROC area under the curve values SmvO2 1.0, ScvO2 0.994, RRS-StO2 0.972, and NIRS-StO2 0.611. CONCLUSION RRS-StO2 seems to have significantly better ability to track central oxygenation measures during hemorrhage as well as to predict shock based on elevated lactate levels when compared with NIRS-StO2.
- Anatomy and Physiology
- Medicine and Medical Research
- Atomic and Molecular Physics and Spectroscopy