Do you have a refractory hypoxemic patient who does not respond to increases in FiO2? Worried about a shunt causing said hypoxemia? Or presence of a septal defect causing paradoxical emboli?

In this screencast done by Dr. Vince Lau, we will go over the principles of intra-atrial septal interrogation, performance of a bubble study, and calculating a shunt fraction (Qp:Qs).