Since its inception in the 1950s, cardiopulmonary bypass has revolutionised cardiac surgery, allowing ever more complex procedures to be undertaken in the knowledge that the bypass circuit is able to provide adequate support to vital organs while the operating surgeon is able to work in a bloodless operative field for several hours. What has changed over the years is the risk profile of the patients for whom cardiac surgery is indicated. The mean age of patients undergoing cardiac surgery in the UK has increased over the past decade with a predictable increase in the range and severity of comorbid conditions observed in patients who come to cardiac surgery today.

The deleterious effects of conventional cardiopulmonary bypass have been known for many years and result primarily from the interaction between the formed elements of blood with the non-physiological surfaces of the cardiopulmonary bypass circuit.1 Platelet and neutrophil activation, consumption of coagulation factors, complement generation and the release of a multitude of pro-inflammatory mediators are recognised consequences of cardiopulmonary bypass.2 A systemic inflammatory response is an inevitable consequence of cardiopulmonary bypass and on occasions may be of sufficient severity as to predispose patients to multiorgan failure. “Off-pump” surgery for the epicardial coronary vessels was driven by a desire to avoid the unwanted effects of cardiopulmonary bypass, but the technique has not proved to be the panacea that was once envisaged3 4 and indeed cannot be applied to intracardiac surgery such as heart-valve …