Temperature difference between jugular bulb and pulmonary artery is associated with neurological outcome in patients with severe traumatic brain injury: A post hoc analysis of a brain hypothermia study

BACKGROUND: The purpose of this study was to examine whether the temperature difference between the jugular bulb and pulmonary artery (ΔT(jb-pa)) is associated with the neurological outcome of patients with severe traumatic brain injury (TBI). METHODS: We conducted a post hoc analysis of a multicenter randomized controlled trial of mild therapeutic hypothermia (TH, 32.0–34.0°C) or fever control (FC, 35.5–37.0°C) for the patients with severe TBI. ΔT(jb-pa) averaged every 12 h and the variation in ΔT(jb-pa) were compared between patients with favorable (n = 39) and unfavorable (n = 37) neurological outcomes. These values were also compared in the TH and FC subgroups. RESULTS: The average ΔT(jb-pa) values in patients with favorable and unfavorable outcomes were 0.24 ± 0.23 and 0.06 ± 0.36°C, respectively (P < 0.001). ΔT(jb-pa) trended significantly higher in the favorable outcome patients than in the unfavorable outcome patients throughout the 120 h after onset of severe TBI (P < 0.001). The variation in ΔT(jb-pa) from 0 to 72 h was significantly lower in the favorable outcome patients than in the unfavorable outcome patients (0.8 ± 0.8 vs 1.8 ± 2.5°C, respectively, P = 0.013). From 72 to 120 h, there was no significant difference in the variation in ΔT(jb-pa). Significant differences between patients with favorable and unfavorable outcomes in ΔT(jb-pa) and the variation in ΔT(jb-pa) were similar in the TH subgroup, but not evident in the FC subgroup. CONCLUSIONS: A reduction in ΔT(jb-pa) and greater variation in ΔT(jb-pa) were associated with an unfavorable outcome in patients with severe TBI, especially those treated with TH. When treating severe TBI patients, it is important to understand that there will be differences in temperature reflecting the brain environment and the systemic temperature, depending on the severity and outcome of TBI during TH.