Abstract 2273: Hyperbaric Oxygen Preconditioning Cost-Effectively Induces Cardiovascular Protection & Improves Clinical Outcome Following Ischemic Reperfusion Injury
Objective To assess the bioclinical and economic effects of HBO preconditioning on cardiovascular function post ischemic reperfusion injury (IRI).
Methods This randomised control study consisted of 40 Control and 41 HBO patients having coronary artery bypass graft (CABG). HBO preconditioning started 4 hours before CABG for 90 minutes at 2.4 ATA using 100% oxygen. Blood soluble intercellular adhesion molecule (sICAM)-1 and Troponin-T was assessed pre and post HBO and, at various times intra and post operatively up to 24 hours post cardiopulmonary bypass (CPB). 4 intra-operative right atrial biopsies were assessed for endothelial Nitric Oxide Synthase (eNOS) and Heat Shock Protein 72 (Hsp72). Haemodynamic readings were taken pre CPB and at various times up to 24 hours post CPB.
Results Before CPB, HBO Group had lower pulmonary vascular resistance (p=0.03). Post CPB, HBO Group had increased stroke volume (p=0.01), left ventricular stroke work (p=0.005) and left ventricular stroke work index (p=0.02). Post CPB, HBO Group had higher cardiac output (CO). Post HBO, sICAM-1 increased. Post IRI, HBO Group had increased sICAM-1 (p=0.03). Following CPB, HBO Group had a smaller increase in Troponin-T. During IRI, eNOS and Hsp72 inncreased in HBO Group but decreased in Control Group. Intra-operatively, HBO Group had a 39.2% reduction in intra-operative blood loss. Post CABG, HBO Group had a reduction in blood loss (11.2%), blood transfusion (12.7%), low cardiac output syndrome (10.4%), inotorope use (8%), atrial fibrillation (AF) (11%), pulmonary complications (12.7%) and wound infections (7.6%). HBO Group had no neurological and renal complications. HBO patients spent 6 hours less in the ICU, saving US$96.51 per ICU hour and, US$570.57 per patient, thus making a total study savings of US$19,399.10.
Conclusion HBO preconditioning before IRI improves myocardial function and pulmonary vascular flow. This may result from increased sICAM-1 which impairs neutrophil-endothelial adhesion and hence endothelial injury. As HBO preconditioning attenuated post CPB myocardial Troponin-T release and increased post IRI atrial eNOS and Hsp72, this indicates that it induces myocardial protection. It also reduces post CABG ICU stay and cost while improving clinical outcome.