Association Between Early Hyperoxia and Worse Outcomes After Traumatic Brain Injury Early Hyperoxia Worsens Outcomes After TBI

Brenner M, Stein D, Hu P, et al. — Thu, 01 Nov 2012 00:00:00 GMT

Objective

To investigate the relationship between oxygenation and short-term outcomes in patients with traumatic brain injury (TBI).

Design

Logistic regression analysis was used to determine whether average high (>200 mm Hg) or low (<100 mm Hg) PaO₂ levels within the first 24 hours of hospital admission correlated with patient outcomes relative to patients with average PaO₂ levels between 100 and 200 mm Hg.

Setting

Level 1 trauma center.

Patients

We retrospectively reviewed 1547 consecutive patients with severe TBI who survived past 12 hours after hospital admission.

Main Outcome Measures

We measured mortality, intensive care unit length of stay, hospital length of stay, and discharge Glasgow Coma Scale (GCS) score.

Results

Of the 1547 patients, 77% were male and 89% sustained blunt trauma. Mean (SD) age, admission GCS score, and Injury Severity Score were 41.3 (20.6) years, 8.3 (4.7), and 31.9 (12.5), respectively. Mean (SD) intensive care unit length of stay and hospital length of stay were 8.7 (10.5) days and 13.8 (13.7) days, respectively. Mean (SD) discharge GCS score was 10.1 (4.7). The mortality rate was 28%. After controlling for age, sex, Injury Severity Score, mechanism of injury, and admission GCS score, patients with high PaO₂ levels had significantly higher mortality and lower discharge GCS scores than patients with a normal PaO₂ (P < .05). Patients with low PaO₂ levels also had increased mortality (P < .05).

Conclusions

Hyperoxia within the first 24 hours of hospitalization is associated with worse short-term functional outcomes and higher mortality after TBI. Although the mechanism for this has not been completely elucidated, it may involve hyperoxia-induced oxygen-free radical toxicity with or without vasoconstriction. Hyperoxia and hypoxia were found to be equally detrimental to short-term outcomes in patients with TBI. A narrower therapeutic window for oxygenation may improve mortality and functional outcomes.

Hyperoxia and Traumatic Brain Injury Comment on “Early Hyperoxia Worsens Outcomes After Traumatic Brain Injury” Hyperoxia and Traumatic Brain Injury

Cryer H. — Thu, 01 Nov 2012 00:00:00 GMT

Brenner and colleagues have nicely shown that average PaO₂ levels of less than 100 mm Hg or greater than 200 mm Hg are independently associated with higher mortality and worse discharge Glasgow Coma Scale scores in 1547 patients with a brain Abbreviated Injury Score of 3 or greater after risk adjusting for mechanism of injury, age, Injury Severity Score, sex, and admission Glasgow Coma Scale score. It has been well established that hypoxia is detrimental to outcome in brain injury. Because of this, there may be a tendency to give higher levels of oxygen to prevent hypoxia. Indeed, the authors found that 43% of their patients had PaO₂ values greater than 200 mm Hg in the first 24 hours of care. Unfortunately, this hyperoxia appears to be detrimental to outcome compared with normoxia and is just as bad as hypoxia. If true, these are important findings that could change the way we approach patients with traumatic brain injury.

JAMA Surgery: Brain Trauma Topic Collection

Association Between Early Hyperoxia and Worse Outcomes After Traumatic Brain Injury Early Hyperoxia Worsens Outcomes After TBI

Hyperoxia and Traumatic Brain Injury Comment on “Early Hyperoxia Worsens Outcomes After Traumatic Brain Injury” Hyperoxia and Traumatic Brain Injury