Tissue oxygen saturation predicts the need for early blood transfusion in trauma patients

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. In an effort to prospectively examine the usefulness 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 6-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 1 hour after arrival to the trauma bay and the minimum value noted. A minimum StO2 less than 70 per cent correlated with the need for blood transfusion with a sensitivity of 88 per cent and a specificity of 78 per cent. The positive predictive value was 64 per cent and the negative predictive value was 93 per cent. The need for blood transfusion within 24 hours of arrival was not predicted by hypotension, tachycardia, arterial lactate, base deficit, or hemoglobin. StO2 may represent an important screening tool for identifying trauma patients who require blood transfusion or other limited medical resources.