The Biomarkers in the Hyperbaric Oxygen Brain Injury Treatment Trial (BioHOBIT)

The Investigators will obtain an initial set of biospecimens (serum, plasma, CSF, DNA) as soon as feasible after randomization to a HOBIT study arm, but no later than 24 hours from injury. Subsequent biospecimens will be obtained every 8 hours (+/- 1 hour) for the first 24 hours post-enrollment. This will allow the characterization of acute changes in biomarker levels. On study days 2, 3, 5, 7 and 14 biospecimens will be obtained once a day to allow characterization of sub-acute changes in biomarker levels. If feasible, samples should be collected at 8am (+/- 2 hours) to minimize the effects of circadian rhythm on biomarker levels. In addition, during the first 5 days of the study, one set of biospecimen will be collected 4 hours after HBO treatment to examine the acute effects of HBO treatment on biomarkers. This will not apply to those randomized to non-HBOT groups. During the 6-month visit, 1 tablespoon (15 ml) of blood will be collected. In addition, for subjects who have an external ventricular drain in place, 5 cc of CSF will be collected at each time point if feasible. Since subjects are unlikely to have an EVD after the first week post-injury, CSF samples will be collected only for as long as the EVD is in place. BioHOBIT will utilize data collected in the HOBIT trial. This data includes: demographic data and clinical data such as injury characteristics, vital signs, head CT findings, laboratory data and data on physiologic parameters such as intracranial pressure (ICP), partial pressure of brain tissue oxygen (PbtO2), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP), among others.