Prognostic Significance of the Difference Between Mixed and Jugular Venous Oxygen Saturation After Severe Traumatic Brain Injury: A Post Hoc Analysis of the Brain Hypothermia Study.

Abstract

In patients postcardiac arrest, it has been reported that the small value of the difference between mixed venous oxygen saturation (Svo₂) and jugular venous oxygen saturation (Sjvo₂) is associated with poor neurologic outcome. However, the importance of the difference between mixed venous oxygen saturation and jugular venous oxygen saturation (ΔSo₂ [v - jv]) remains unknown in severe traumatic brain injury (TBI). The aim of this study was to examine whether ΔSo₂ (v - jv) is associated with neurologic outcome and mortality in patients with severe TBI. We conducted post hoc analyses of the Brain Hypothermia Study, a multicenter randomized controlled trial of mild therapeutic hypothermia for the treatment of severe TBI. The value of ΔSo₂(v - jv) on day 1 and day 3 was compared between survivors (n = 65) and nonsurvivors (n = 25) or between patients with favorable (n = 47) and unfavorable (n = 43) neurologic outcomes. The reduction in ΔSo₂ (v - jv) on day 3 was -2.0% (range, -6.9% to 6.5%) in the nonsurvivor group and 6.3% (range, -2.5% to 16.7%) in the survivor group. The difference was statistically significant (P = 0.03). The same tendencies were observed in the nonsurvivor group on day 1 and in the unfavorable neurologic outcome group on day 1 and day 3, but the difference was not significant. The reduction in ΔSo₂(v - jv) on day 3 was associated with high mortality in patients with severe TBI.