TY - JOUR
T1 - Normobaric hyperoxia in traumatic brain injury: Does brain metabolic state influence the response to hyperoxic challenge?
AU - Vilalta, Anna
AU - Sahuquillo, Juan
AU - Merino, Maria Angels
AU - Poca, Maria Antonia
AU - Garnacho, Angel
AU - Martínez-Valverde, Tamara
AU - Dronavalli, Mithilesh
PY - 2011/7/1
Y1 - 2011/7/1
N2 - This study sought to investigate whether normobaric hyperoxia (NH) improves brain oxygenation and brain metabolism in the early phase of severe and moderate traumatic brain injury (TBI) and whether this effect occurs uniformly in all TBI patients. Thirty patients (9 women and 21 men) with a median initial Glasgow Coma Score (GCS) of 6 (range, 3-12) were monitored using a brain microdialysis (MD) catheter with a brain tissue oxygen sensor (PtiO2) placed in the least-injured hemisphere. The inspired oxygen fraction was increased to 100% for 2h. Patients were divided into two groups: Group 1: patients with baseline brain lactate ?3mmol/L and Group 2: patients with baseline brain lactate >3mmol/L, and therefore increased anaerobic metabolism in the brain. In Group 1, no significant changes in brain metabolic parameters were found after hyperoxic challenge, whereas a significant increase in glucose and a decrease in the lactate-pyruvate ratio (LPR) were found in Group 2. In this latter group of patients, brain glucose increased on average by 17.9% (95% CI, +9.2% to +26.6%, p<0.001) and LPR decreased by 11.6% (95% CI, -16.2% to -6.9%, p<0.001). The results of our study show that moderate and severe TBI may induce metabolic alterations in the brain, even in macroscopically normal brain tissue. We observed that NH increased PaO2 and PtiO2 and significantly decreased LPR in patients in whom baseline brain lactate levels were increased, suggesting that NH improved the brain redox state. In patients with normal baseline brain lactate levels, we did not find any significant changes in the metabolic variables after NH. This suggests that the baseline metabolic state should be taken into account when applying NH to patients with TBI. This maneuver may only be effective in a specific group of patients. © 2011, Mary Ann Liebert, Inc.
AB - This study sought to investigate whether normobaric hyperoxia (NH) improves brain oxygenation and brain metabolism in the early phase of severe and moderate traumatic brain injury (TBI) and whether this effect occurs uniformly in all TBI patients. Thirty patients (9 women and 21 men) with a median initial Glasgow Coma Score (GCS) of 6 (range, 3-12) were monitored using a brain microdialysis (MD) catheter with a brain tissue oxygen sensor (PtiO2) placed in the least-injured hemisphere. The inspired oxygen fraction was increased to 100% for 2h. Patients were divided into two groups: Group 1: patients with baseline brain lactate ?3mmol/L and Group 2: patients with baseline brain lactate >3mmol/L, and therefore increased anaerobic metabolism in the brain. In Group 1, no significant changes in brain metabolic parameters were found after hyperoxic challenge, whereas a significant increase in glucose and a decrease in the lactate-pyruvate ratio (LPR) were found in Group 2. In this latter group of patients, brain glucose increased on average by 17.9% (95% CI, +9.2% to +26.6%, p<0.001) and LPR decreased by 11.6% (95% CI, -16.2% to -6.9%, p<0.001). The results of our study show that moderate and severe TBI may induce metabolic alterations in the brain, even in macroscopically normal brain tissue. We observed that NH increased PaO2 and PtiO2 and significantly decreased LPR in patients in whom baseline brain lactate levels were increased, suggesting that NH improved the brain redox state. In patients with normal baseline brain lactate levels, we did not find any significant changes in the metabolic variables after NH. This suggests that the baseline metabolic state should be taken into account when applying NH to patients with TBI. This maneuver may only be effective in a specific group of patients. © 2011, Mary Ann Liebert, Inc.
KW - anaerobic metabolism
KW - brain tissue oxygen pressure
KW - cerebral metabolism
KW - hyperoxia
KW - MD
KW - mitochondrial dysfunction
KW - NH
KW - TBI
U2 - 10.1089/neu.2010.1720
DO - 10.1089/neu.2010.1720
M3 - Article
VL - 28
SP - 1139
EP - 1148
IS - 7
ER -