title: Tissue oxygenation monitoring using resonance Raman spectroscopy during hemorrhage.
abstract: 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 as well as with near-infrared spectroscopy tissue hemoglobin oxygenation (NIRS-StO2).
  
  
  
  Five male swine were anesthetized and instrumented followed by hemorrhage at a rate of 30 mL/min 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.
  
  
  
  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).
  
  
  
  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.
authors.affiliation: From the Department of Emergency Medicine (M.H.T., G.T.D., K.R.W.) and the Michigan Center for Integrative Research in Critical Care (M.H.T., G.T.D., K.R.W.), University of Michigan, Ann Arbor, Michigan; Departments of Emergency Medicine (R.W.B.) and Chemistry (J.T.), the Virginia Commonwealth University Reanimation Engineering Science Center (R.W.B., J.T.), Virginia Commonwealth University, Richmond, Virginia; Damage Control Resuscitation (I.T.F.), US Army Institute for Surgical Research, Fort Sam Houston, San Antonio, Texas; Pendar Medical (P.R., D.V.), Cambridge, Massachusetts.
authors.forename: Mohamad H
authors.initials: MH
authors.lastname: Tiba
authors.forename: Gerard T
authors.initials: GT
authors.lastname: Draucker
authors.forename: Robert W
authors.initials: RW
authors.lastname: Barbee
authors.forename: James
authors.initials: J
authors.lastname: Terner
authors.forename: Ivo
authors.initials: I
authors.lastname: Torres Filho
authors.forename: Padraic
authors.initials: P
authors.lastname: Romfh
authors.forename: Daryoosh
authors.initials: D
authors.lastname: Vakhshoori
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Ward
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D016001:Confidence Intervals; D004195:Disease Models, Animal; D018450:Disease Progression; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism; D006470:Hemorrhage / Q000150:complications / Q000175:diagnosis; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D009061:Mouth Mucosa / Q000098:blood supply; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology; D012372:ROC Curve; D011897:Random Allocation; D012680:Sensitivity and Specificity; D012771:Shock, Hemorrhagic / Q000175:diagnosis*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013552:Swine
chemical_list: D006454:Hemoglobins; D010100:Oxygen