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.

Background: In patients postcardiac arrest, it has been reported that the small value of the difference between mixed venous oxygen saturation (Svo) and jugular venous oxygen saturation (Sjvo) is associated with poor neurologic outcome. However, the importance of the difference between mixed venous oxygen saturation and jugular venous oxygen saturation (ΔSo [v - jv]) remains unknown in severe traumatic brain injury (TBI). The aim of this study was to examine whether ΔSo (v - jv) is associated with neurologic outcome and mortality in patients with severe TBI.

Methods: 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 ΔSo(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.

Results: The reduction in ΔSo (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.

Conclusions: The reduction in ΔSo(v - jv) on day 3 was associated with high mortality in patients with severe TBI.