Cardiopulmonary bypass

Abstract 

Extracorporeal cardiopulmonary bypass (CPB) facilitates surgery on the surface and within the chambers of the heart. It provides the function of the heart and lungs, giving the blood momentum and carrying out gas exchange, respectively. CPB allows the heart and lungs to be isolated from the systemic circulation.

CPB was first used by John Gibbon (Pennsylvania, USA) in 1953 to close an atrial septal defect in 18-year-old female. Improvements in the technology, management and understanding of CPB have significantly contributed to a reduction in morbidity and mortality since then. It has enabled a shift towards surgery in older patients who are likely to have more co-morbid conditions.

This overview examines the cannulation sites necessary for CPB, their importance and the options available. Description of the extracorporeal circuit focuses on the materials used and the properties of the components. The non-physiological aspects of these components are highlighted and the importance of full anticoagulation for extracorporeal support explained. Associated CPB techniques (including myocardial protection during crossclamping of the aorta and deep hypothermic arrest) are detailed. This contribution gives an insight into the acute and long-term complications of CPB; it also discusses the support devices allied with cardiac surgery, from intra- aortic balloon counterpulsation to the components of long-term extracorporeal membrane oxygenation.

Keywords: cardiopulmonary bypass, perfusion, anticoagulation, oxygenator, inflammatory response, activated clotting time, myocardial protection, cannulation, ECMO