What do perfusionists (clinical perfusion scientists) do?

Perfusionists are specially trained healthcare scientists who form a vital part of the “open-heart surgery” team in cardiac operating theatres and peri-operative care. The perfusionist is responsible for running equipment to perform cardiopulmonary bypass (CPB), known colloquially as the heart-lung machine. This technique utilises extracorporeal circuits, blood pumps and artificial lungs (membrane oxygenators) that are necessary to completely take over the function of the heart and lungs during cardiac surgical procedures. Patients range from neonates to fully grown adults.

As clinical and technical experts in extracorporeal life support (ECLS), perfusionists are also involved with extracorporeal membrane oxygenation (ECMO) therapy. ECMO is a form of ECLS, which has evolved from standard operating theatre CPB. It can be used to treat acute, severe respiratory and/or cardiac failure for a period of hours to several months. Other modalities of mechanical circulatory life support, including intra-aortic balloon pumps (IABP) and ventricular assist devices (‘artificial hearts’), also fall within the realm of the perfusionist’s unique knowledge base and skillset.

In addition, perfusionists are responsible for blood conservation programmes within the units in which they work. Such programmes involve cell salvage, where shed blood from the surgical field can be processed and returned to the patient without the need for donated blood. These services also utilise point of care testing (POCT) blood analysis to enable rational use of blood and blood products (for example, platelets and coagulation factors) for transfusion.

How did the role of perfusionists come about?

Prior to the advent of CPB, operating on the heart was considered unchartered territory, foolhardy, and somewhat cavalier in surgical circles. Since its introduction in the 1950s, CPB has facilitated ideal cardiac surgical operating conditions – namely a bloodless surgical field, controlled arrest of the heart, and negating the requirement for mechanical ventilation of the lungs. Indeed, such things complicated the endeavours of the early pioneers of cardiac surgery, and required them to be brave of heart (excuse the pun) and quick of hand!

During CPB, the perfusionist is responsible for manipulating, on a moment-to-moment basis, vital physiological parameters whilst the surgeon operates on the heart. They also administer drugs and undertake blood transfusion and haemofiltration. 

Traditionally, the role of the perfusionist was non-specific and undertaken by any member of the surgical team willing to have a go(!). Over the last few decades, the clinical perfusion profession has evolved into a highly specialised, niche area of peri-operative practice. Entry is postgraduate only, with prospective trainees requiring a 2:1 BSc degree in a life or physical science. Trainees spend two years performing supervised cases in a cardiothoracic centre and studying at the University of Bristol, undertaking a blended learning MSc in Perfusion Science, which is a rigorous clinical and academic apprenticeship. 

Where do perfusionists work?

Until relatively recently, the perfusionist was mainly confined to the operating theatre. However, the skills and knowledge of the perfusionist are often called upon in other settings where ECLS is used – for example, to place critically ill patients on ECMO/CPB in the intensive care unit, catheterisation laboratories and even the emergency department. In centres that are commissioned to provide ECMO, perfusionists form part of the retrieval team that travel to other hospitals by land (and occasionally sea or air!) to initiate ECMO support and transport patients back to the ECMO centre for ongoing intensive care.

How do perfusionists interact with hospital staff?

As a vital part of the cardiothoracic surgical team, the perfusionist works closely with cardiac surgeons, theatre nurses, anaesthetists, ODPs, cardiac physiologists, and theatre support workers/HCAs/porters. Perfusionists also interact with staff in the intensive care unit, surgical wards and cardiac catheterisation laboratories.

Clinical perfusion, like anaesthesia, is a very-safety oriented profession. There are multiple hazards and potential risks to patient safety when undertaking extracorporeal support of the patient’s circulation. As such, concentrating for long periods of time, effective communication, meticulous attention to detail, clinical problem-solving, and the ability to deal with highly stressful and emotive emergency situations are essential attributes of the practicing perfusionist.

Further information

The Society of Clinical Perfusion Scientists of Great Britain & Ireland: https://www.scps.org.uk/ 

University of Bristol MSc Perfusion Science: http://www.bristol.ac.uk/study/postgraduate/2019/health-sciences/msc-perfusion-science/