The PAC, invented by Jeremy Swan and William Ganz in 1970, is a 150cm-long, balloon-tipped catheter inserted into a large vein, most commonly the right internal jugular, through a ‘PA sheath’. It is advanced through the SVC, right atrium and the tricuspid valve into the right ventricle. At this point, the balloon at the tip is inflated via a syringe connected to its corresponding port. The inflated balloon aids correct catheter placement, via the flow of blood, through the pulmonary valve into