Pretreatment with hyperbaric oxygen and its effect on neuropsychometric dysfunction and systemic inflammatory response after cardiopulmonary bypass: a prospective randomized double-blind trial.
OBJECTIVE
Animal studies have shown that pretreatment with hyperbaric oxygen can induce central nervous system ischemic tolerance and also modulate the inflammatory response. We evaluated this therapy in patients undergoing cardiopulmonary bypass.


METHODS
Sixty-four patients were prospectively randomized to group A (n = 31; atmospheric air, 1.5 atmospheres absolute) or group B (n = 33; hyperbaric oxygen, 2.4 atmospheres absolute) before on-pump coronary artery bypass grafting. Age, sex, body mass index, diabetes, hypertension, smoking, coronary disease severity, left ventricular function, Parsonnet score, Euroscore, bypass time, myocardial ischemia time, and number of grafts were comparable in both groups. Canadian Cardiovascular Society angina, New York Heart Association dyspnea, and previous myocardial infarction were significantly higher in group B. Inflammatory markers were analyzed before surgery and 2 and 24 hours after bypass. Neuropsychometric testing was performed 48 hours before surgery and 4 months after surgery and included trail making A and B, the Rey auditory verbal learning test, grooved peg board, information processing table A, and digit span forward and backward. Neuropsychometric dysfunction was defined as more than 1 SD deterioration in more than 2 neuropsychometric tests. Chi-square tests, Fisher tests, t tests, and analysis of variance were used as appropriate for statistical analysis.


RESULTS
Group A had a significant postoperative increase in the inflammatory markers soluble E-selectin, CD18, and heat shock protein 70. This was not observed in group B. Neuropsychometric dysfunction was also significantly higher in group A compared with group B. There was no difference in any other early postoperative clinical outcome.


CONCLUSIONS
Our results seem to indicate that pretreatment with hyperbaric oxygen can reduce neuropsychometric dysfunction and also modulate the inflammatory response after cardiopulmonary bypass. However, further multicenter randomized trials are needed to clinically evaluate this form of therapy.
Alex
Joseph
J
Department of Cardiothoracic Surgery, Castle Hill Hospital, United Kingdom. mrjosephalex@yahoo.co.uk
Laden
Gerard
G
Cale
Alex R J
AR
Bennett
Sean
S
Flowers
Kenneth
K
Madden
Leigh
L
Gardiner
Eric
E
McCollum
Peter T
PT
Griffin
Steven C
SC
D000368:Aged; D001927:Brain Diseases / Q000209:etiology / Q000517:prevention & control*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation; D007249:Inflammation / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D009483:Neuropsychological Tests; D011300:Preoperative Care; D011446:Prospective Studies