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

Abstract 

Objective

The 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.

Methods

This 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.

Results

Prior 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.

Conclusion

This 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.

Keywords: Hyperbaric oxygen, Ischemic reperfusion injury, CABG