Tissue oxygen saturation predicts the development of organ dysfunction during traumatic shock resuscitation

Background: Near-infrared spectroscopy (NIRS) can continuously and noninvasively monitor tissue oxygen saturation (StO(2)) in muscle and may be an indicator of shock severity. Our purpose was to evaluate how well StO(2) predicted outcome in high-risk torso trauma patients presenting in shock. Methods: The primary outcome in this prospective study was multiple organ dysfunction syndrome (MODS). StO(2) data were obtained upon hospital arrival and for 24 hours along with other known predictors of hypoperfusion and clinical outcomes. Clinicians were blinded to StO(2) measurements. Results: Seven Level I trauma centers enrolled 383 patients, 50 of whom developed MODS. Minimum StO(2) performed similarly to maximum base deficit (BD) in discrimination of MODS patients. The sensitivity for both measures (StO(2) cutoff = 75%; BD cutoff = 6 mEq/L)was 78%, the specificity was 34% to 39%, the positive predictive value was 18% to 20% and the negative predictive value was 88% to 91%. StO(2) and BD were also comparable in predicting death. Conclusions: NIRS-derived muscle StO(2) measurements perform similarly to BD in identifying poor perfusion and predicting the development of MODS or death after severe torso trauma, yet have the additional advantages of being continuous and noninvasive.