Hyperbaric side effects in a traumatic brain injury randomized clinical trial.

OBJECTIVE: To catalog the side effects of 2.4 atmospheres absolute (atm abs) hyperbaric oxygen (HBO2) vs. sham on post-concussion symptoms in military service members with combat-related, mild traumatic brain injury (TBI). METHODS: Fifty subjects diagnosed with TBI were randomized to either a sham (1.3 atm abs breathing air) or treatment (2.4 atm abs breathing 100% oxygen) hyperbaric profile. Forty-eight subjects completed 30 exposures. Medical events during hyperbaric exposures were separately annotated by medical staff and chamber operators. After the blind was broken, events were segregated into the exposure groups. RESULTS: These side effects were observed as rate (sham/treatment): ear block (ear barotrauma) 5.51% (1.09%/5.91%), sinus squeeze 0.14% (0.0%/0.27%), and confinement anxiety 0.27% (0.27%/0.27%). Other conditions that occurred included: headache 0.61% (0.68%/0.54%); nausea 0.2% (0.14%/0.27%); numbness 0.07% (0%/0.13%); heartburn 0.07% (0.14%/0%); musculoskeletal chest pain 0.07% (0%/0.13%); latex allergy 0.07% (0.14%/0%); and hypertension 0.07% (0.14%/0%). CONCLUSION: This study demonstrated no major adverse events, such as pulmonary barotraumas, pulmonary edema or seizure. Given the infrequent, mild side effect profile, the authors feel the study demonstrated that hyperbaric oxygen therapy (HBO2T) was safe at a relatively high treatment pressure in TBI subjects, and these data can be used to evaluate the risk/ benefit calculation when deciding to utilize HBO2T for treatment of various diseases in the TBI population.

Disaster aeromedical evacuation.

Successful disaster aeromedical evacuation depends on applying the principles learned by moving patients since World War II, culminating in today's global patient movement system. This article describes the role of the Department of Defense patient movement system in providing defense support to civil authorities during the 2008 hurricane season and the international disaster response to the 2010 Haiti earthquake. Adapting and applying the principles of active partnerships, establishing patient movement requirements, patient preparation, and in-transit visibility have resulted in the successful aeromedical evacuation of over 1,600 patients since the federal response to Hurricane Katrina.

White matter hyperintensities on MRI in high-altitude U-2 pilots.

OBJECTIVE: To demonstrate that U-2 pilot occupational exposure to hypobaria leads to increased incidence of white matter hyperintensities (WMH) with a more uniform distribution throughout the brain irrespective of clinical neurologic decompression sickness history. METHODS: We evaluated imaging findings in 102 U-2 pilots and 91 controls matched for age, health, and education levels. Three-dimensional, T2-weighted, high-resolution (1-mm isotropic) imaging data were collected using fluid-attenuated inversion recovery sequence on a 3-tesla MRI scanner. Whole-brain and regional WMH volume and number were compared between groups using a 2-tailed Wilcoxon rank sum test. RESULTS: U-2 pilots demonstrated an increase in volume (394%; p = 0.004) and number (295%; p < 0.001) of WMH. Analysis of regional distribution demonstrated WMH more uniformly distributed throughout the brain in U-2 pilots compared with mainly frontal distribution in controls. CONCLUSION: Pilots with occupational exposure to hypobaria showed a significant increase in WMH lesion volume and number. Unlike the healthy controls with predominantly WMH in the frontal white matter, WMH in pilots were more uniformly distributed throughout the brain. This is consistent with our hypothesized pattern of damage produced by interaction between microemboli and cerebral tissue, leading to thrombosis, coagulation, inflammation, and/or activation of innate immune response, although further studies will be necessary to clarify the pathologic mechanisms responsible.

The effect of hyperbaric oxygen on symptoms after mild traumatic brain injury.

In this single-center, double-blind, randomized, sham-controlled, prospective trial at the U.S. Air Force School of Aerospace Medicine, the effects of 2.4 atmospheres absolute (ATA) hyperbaric oxygen (HBO2) on post-concussion symptoms in 50 military service members with at least one combat-related, mild traumatic brain injury were examined. Each subject received 30 sessions of either a sham compression (room air at 1.3 ATA) or HBO2 treatments at 2.4 ATA over an 8-week period. Individual and total symptoms scores on Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®) and composite scores on Post-traumatic Disorder Check List-Military Version (PCL-M) were measured just prior to intervention and 6 weeks after completion of intervention. Difference testing of post-intervention means between the sham-control and HBO2 group revealed no significant differences on the PCL-M composite score (t=-0.205, p=0.84) or on the ImPACT total score (t=-0.943, p=0.35), demonstrating no significant effect for HBO2 at 2.4 ATA. PCL-M composite scores and ImPACT total scores for sham-control and HBO(2) groups revealed significant improvement over the course of the study for both the sham-control group (t=3.76, p=0.001) and the HBO2 group (t=3.90, p=0.001), demonstrating no significant HBO2 effect. Paired t-test results revealed 10 ImPACT scale scores in the sham-control group improved from pre- to post-testing, whereas two scale scores significantly improved in the HBO2 group. One PCL-M measure improved from pre- to post-testing in both groups. This study showed that HBO2 at 2.4 ATA pressure had no effect on post-concussive symptoms after mild TBI.