NEW ORLEANS — Spending a few hours in a hyperbaric chamber before undergoing on-pump coronary artery bypass graft surgery markedly reduces postoperative neurocognitive dysfunction, according to the findings of a randomized double-blind trial.
The trial included 64 patients scheduled for on-pump CABG surgery, who spent three sessions inside a hyperbaric chamber at 24, 12, and 4 hours prior to their surgery. During each session, they were exposed to 60 minutes of 100% oxygen at either 2.4 atm of pressure or normobaric room air. Surgeons, patients, and the neuropsychologist were blinded to which treatment the patient received, Joseph Alex, M.D., said at the annual scientific sessions of the American Heart Association.
A battery of neuropsychological tests was administered 1 week before and again 4 months following CABG surgery. Significant neurocognitive dysfunction—a decline of at least 1 standard deviation on any two tests in the battery—was documented in 55% of control subjects and 30% of patients who underwent hyperbaric oxygenation before surgery, according to Dr. Alex of Castle Hill Hospital, Cottingham, and the University of Hull, England.
The two patient groups in the study were comparable in terms of all key perioperative variables that might have affected neurocognitive function, including time spent on a ventilator, need for and length of ICU stay, blood transfusion, development of renal dysfunction, and cardiac arrhythmias.
The neuropsychologic test battery consisted of the digit-span forward and backward, the grooved peg board, the Rey Auditory-Verbal Learning Test, trail-making A and B, and the adult memory and information processing table A.
Patients who underwent preoperative hyperoxygenation not only had less neurocognitive impairment; they also showed significantly less postoperative anxiety and depression symptoms, Dr. Alex added.
The increased tissue oxygen concentrations achieved in the hyperbaric chamber have been shown to promote healing of refractory leg ulcers and other wounds.