Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Smith J, Bricker S, Putnam B. 19th Annual Scientific Meeting of the Southern California Chapter of the American College of Surgeons; January 18-20, 2008; Santa Barbara, CA.
Near-infrared spectroscopy (NIRS) has been used to measure regional tissue oxygen saturation (StO2) in skeletal muscle as an indicator of perfusion in trauma patients. Previous studies have demonstrated the ability of StO2 to predict the onset of organ dysfunction and mortality. In an effort to prospectively examine the utility of StO2 in identifying trauma patients in hemorrhagic shock, we evaluated the need for blood transfusion within 24 hours of injury as a marker of significant hemorrhage. A six month prospective, observational study was conducted at a university-affiliated, urban level I trauma center, using a convenience sample of 26 trauma patients thought to be at high risk for hemorrhagic shock. Baseline demographic data, vital signs, laboratory values, and amounts of fluid and blood products administered were collected. NIRS-derived StO2 values were measured for one hour after arrival to the trauma bay and the minimum value noted. Patients were divided into groups based on a minimum StO2 value within one hour of arrival with a 70% StO2 cutoff. Patients with an StO2 > 70% were similar to patients with an StO2 ¡Ü 70% with regard to age, sex, mechanism of injury, Injury Severity Score (ISS), and Revised Trauma Score (RTS). A minimum StO2 < 70% correlated with the need for blood transfusion with a sensitivity of 88% and a specificity of 78%. The positive predictive value was 64% and the negative predictive value was 93%. Logistic regression revealed a correlation of R2=0.890. The need for blood transfusion within 24 hours of arrival was not predicted by hypotension, tachycardia, arterial lactate, base deficit, or hemoglobin. Patients with an StO2 > 70% had a longer hospital length of stay (LOS) than those with an StO2 ¡Ü 70%, although there was no observed difference in mortality between the groups. StO2 may represent an important screening tool for identifying trauma patients who require blood transfusion or other limited medical resources.