medwireNews: Combining hyperbaric oxygen (HBO2) and normobaric hyperoxia (NBH) into a single treatment improves outcomes for patients who have sustained severe traumatic brain injury, according to a phase II study.
In comparison to standard care, the combined HBO2/NBH treatment significantly improved markers for oxidative metabolism in uninjured brain and pericontusional tissue, as well as reducing intracranial hypertension, and improving cerebral toxicity markers.
The treatment also significantly reduced mortality and improved favorable outcomes compared with standard care consisting of oxygen delivery aims to maintain a sufficient oxygen supply to the brain by avoiding increased intracranial pressure (ICP) and ensuring a sufficient cerebral perfusion pressure (CPP).
"The combination of HBO2 and NBH therapy appears to have potential therapeutic efficacy as compared with the 2 treatments in isolation," suggest Gaylan Rockswold (Hennepin County Medical Center, Minneapolis, Minnesota) and colleagues in the Journal of Neurosurgery.
The study randomly grouped 42 patients, who did not demographically differ, within 24 hours of sustaining a severe traumatic brain injury. The treatment group consisted of 20 patients who received a 100% fraction of inspired oxygen for 60 minutes at 1.5 atmospheres absolute (HBO2) followed by 3 hours of oxygen at 1.0 atmospheres absolute (NBH). The control group of 22 patients received standard care.
Oxygen treatment was given once every 24 hours for 3 consecutive days, and was administered as soon as entry criteria were met and a patient's condition was clinically stable. Clinical outcomes were assessed 6 months later.
In comparison with the control group, HBO2/NBH-treated patients had significantly higher brain tissue partial pressure (PO2) during and following treatment in both the noninjured and pericontusional brain, with PO2 remaining approximately 50% higher for 2.5 hours after the combined treatment.
The treatment groups also had significantly lower microdialysate lactate/pyruvate ratios in the noninjured brain, indicating better cerebral metabolism.
Combined HBO2/NBH treatment kept microdialysate glycerol at levels that indicated no signs of cerebral and pulmonary O2 toxicity.
The 6-month follow-up of 19 HBO2/NBH treatment and 21 control patients found a mortality rate of 16% and 42%, respectively - a significantly different absolute reduction of 26%. Analysis at this time also revealed that 38% of the control group and 74% of the treatment group had favorable outcomes, based on the Glasgow Outcome Scale, a significant absolute difference of 36%.
Overall, "combining HBO2 and NBH into a single treatment potentially has a synergistic therapeutic effect," the authors conclude. "This improvement was significantly better than past clinical outcomes observed with either of the treatments used separately."