Hyperbaric oxygen preconditioning improves myocardial function, reduces length of intensive care stay, and limits complications post coronary artery bypass graft surgery ★

ObjectiveThe objective of this study was to determine whether preconditioning coronary artery disease (CAD) patients with HBO2 prior to first-time elective on-pump cardiopulmonary bypass (CPB) coronary artery bypass graft surgery (CABG) leads to improved myocardial left ventricular stroke work (LVSW) post CABG. The primary end point of this study was to demonstrate that preconditioning CAD patients with HBO2 prior to on-pump CPB CABG leads to a statistically significant (P<.05) improvement in myocardial LVSW 24 h post CABG.MethodsThis randomised control study consisted of 81 (control group=40; HBO2 group=41) patients who had CABG using CPB. Only the HBO2 group received HBO2 preconditioning for two 30-min intervals separated 5 min apart. HBO2 treatment consisted of 100% oxygen at 2.4 ATA. Pulmonary artery catheters were used to obtain perioperative hemodynamic measurements. All routine perioperative clinical outcomes were recorded. Venous blood was taken pre HBO2, post HBO2 (HBO2 group only), and during the perioperative period for analysis of troponin T.ResultsPrior to CPB, the HBO2 group had significantly lower pulmonary vascular resistance (P=.03). Post CPB, the HBO2 group had increased stroke volume (P=.01) and LVSW (P=.005). Following CABG, there was a smaller rise in troponin T in HBO2 group suggesting that HBO2 preconditioning prior to CABG leads to less postoperative myocardial injury. Post CABG, patients in the HBO2 group had an 18% (P=.05) reduction in length of stay in the intensive care unit (ICU). Intraoperatively, the HBO2 group had a 57% reduction in intraoperative blood loss (P=.02). Postoperatively, the HBO2 group had a reduction in blood loss (11.6%), blood transfusion (34%), low cardiac output syndrome (10.4%), inotrope use (8%), atrial fibrillation (11%), pulmonary complications (12.7%), and wound infections (7.6%). Patients in the HBO2 group saved US$116.49 per ICU hour.ConclusionThis study met its primary end point and demonstrated that preconditioning CAD patients with HBO2 prior to on-pump CPB CABG was capable of improving LVSW. Additionally, this study also showed that HBO2 preconditioning prior to CABG reduced myocardial injury, intraoperative blood loss, ICU length of stay, postoperative complications, and saved on cost, post CABG.