The National Brain Injury Rescue and Rehabilitation Study - a multicenter observational study of hyperbaric oxygen for mild traumatic brain injury with post-concussive symptoms

The National Brain Injury Rescue and Rehabilitation Project was established as a preliminary study to test the safety and practicality of multi-center hyperbaric oxygen administration for the post-concussive symptoms of chronic mild traumatic brain injury as a precursor to a pivotal, independent, multi-center, controlled clinical trial. This report presents the results for 32 subjects who completed a preliminary trial of hyperbaric oxygen several years before the passage of the 21 ^st Century Cures Act. This study anticipated the Act and its reassessment of clinical research. Subjects received 40-82 one-hour treatments at 1.5 atmospheres absolute 100% oxygen. Outcome measures included repeated self-assessment measures and automated neurocognitive tests. The subjects demonstrated improvement in 21 of 25 neurocognitive test measures observed. The objective neurocognitive test components showed improvement in 13 of 17 measures. Earlier administration of hyperbaric oxygen post injury, younger age at the time of injury and hyperbaric oxygen administration, military status, and increased number of hyperbaric oxygen administrations were characteristics associated with improved outcomes. There were no adverse events. Hyperbaric oxygen was found to be safe, inexpensive and worthy of clinical application in the 21 ^st Century model of facile data collection provided by recent research regulatory shifts in medicine. The study was approved by the ethics review committee of the Western Institutional Review Board (WIRB; Protocol #20090761).

The predictive value of transcutaneous oxygen tension measurement in diabetic lower extremity ulcers treated with hyperbaric oxygen therapy: a retrospective analysis of 1,144 patients

The objective of this retrospective analysis was to determine the reliability of transcutaneous oxygen tension measurement (TcPO2) in predicting outcomes of diabetics who underwent hyperbaric oxygen therapy for lower extremity wounds. Six hyperbaric facilities provided TcPO2 data under several possible conditions: breathing air, breathing oxygen at sea level, and breathing oxygen in the chamber. Overall, 75.6% of the patients improved after hyperbaric oxygen therapy. Baseline sea-level air TcPO2 identified the degree of tissue hypoxia but had little statistical relationship with outcome prediction because some patients healed after hyperbaric oxygen therapy despite very low prehyperbaric TcPO2 values. Breathing oxygen at sea level was unreliable for predicting failure, but 68% reliable for predicting success after hyperbaric oxygen therapy. TcPO2 measured in chamber provides the best single discriminator between success and failure of hyperbaric oxygen therapy using a cutoff score of 200 mmHg. The reliability of in-chamber TcPO2 as an isolated measure was 74% with a positive predictive value of 58%. Better results can be obtained by combining information about sea-level air and in-chamber oxygen. A sea-level air TcPO2 < 15 mmHg combined with an in-chamber TcPO2 < 400 mmHg predicts failure of hyperbaric oxygen therapy with a reliability of 75.8% and a positive predictive value of 73.3%.

Mass-producible microscopic computer-generated holograms: microtags

We have developed a method for encoding phase and amplitude in microscopic computer-generated holograms (microtags) for security applications. An 8 x 8 cell phase-only and an 8 x 8 cell phase-and-amplitude microtag design has been exposed in photoresist by the extreme-ultraviolet (13.4-nm) lithography tool developed at Sandia National Laboratories. Each microtag measures 80 microm x 160 microm and contains features that are 0.2 microm wide. Fraunhofer zone diffraction patterns can be obtained from fabricated microtags without any intervening optics and compare favorably with predicted diffraction patterns.

Glucose intolerance in man during prolonged exposure to a hypobaric-hyperoxic environment

Eight subjects were exposed to a hypobaric (258 mm. Hg)-hyperoxic (100 per cent oxygen) environment for thirty days. Standard oral glucose tests were done during a control period of normal pressure and atmosphere, twenty-four hours after completing the thirty-day exposure and during a fifteen-day recovery. Exercise was uniform during the control period; however, during exposure and recovery periods four subjects continued daily exercise and the other four were maintained on limited activity (bedrest with bathroom privileges). Diet was constant throughout, containing 350 gm. of carbohydrates. Mean exposure period fasting (104.5 ± 6.5 mg./100 ml. S.E.M.) and sixty-minute (145 ± 18.5 mg./100. ml.) glucose values were significantly greater than corresponding control period fasting (87.1 ± 1.6 mg./ 100 ml.) and sixty-minute (105 ± 4.6 mg./100 ml.) control values. Mean plasma glucose values at 120 and 180 minutes during exposure to the test atmosphere were greater, but not significantly different than during control periods. Results of the glucose tolerance tests done fifteen days postexposure showed mean fasting 60-, 120- and 180-minute values to be significantly higher than the pre-exposure controls but similar to the exposure values. Serum immunoreactive insulin concentrations immediately after exposure and during recovery were unchanged from control levels. No difference in either glucose or insulin values could be detected between the exercise and nonexercise groups. It is suggested that prolonged exposure to hypobaric-hyperoxic environments adversely influences glucose tolerance.