A number of cardiac professionals are now picketing outside UHG in a row over pay conditions.
Perfusionists are highly specialised cardiovascular professionals who operate the machines that take over the work of the heart and lungs during surgery.
They're now engaged in a 24 hour strike at five hospitals nationwide, which has led to some planned cardiac surgeries being cancelled in Dublin, Cork and Galway.
Trade Union Forsa says the row is over the HSE's refusal to implement a Labour Court recommendation to restore pay-links between perfusionists and medical scientists.
Denise is a Perfusionist at UHG and told Sarah Slevin they don't want to be out this morning but they've been given no choice.