Today’s topic is a big one! I start of by assessing the vertical gradient of pleural pressure (01:25). Then discuss a favourite topic closing capacity and its significance (05:53). I then explain the different types of dead space and how this links in West’s Zones of the lung (14:24). Then I look at the opposite spectrum and discuss shunt and all things that are venous admixture (27:04). Putting this together we analyse the regional differences in ventilation and-perfusion inequalities (34:31). Our last learning objective is a brief classification of V/Q measurement techniques (40:23). As always, we end by looking at the key SAQs from the ANZCA and ICU exams (42:25) and then I summarise todays topic (61:56). I will release a Special Episode 2 weeks before the written exam and the next episode we will go through ‘Pulmonary Circulation.' Thanks for listening! As always if you have any feedback let me know!