Thanks for checking out the video and glad it was stimulating! Good old physics finds itself everywhere!

Wonderful! Thanks for checking out the video and good luck as you continue on in your studies!

That is fair! There is that brief increase in LV preload as the pulmonary vasculature shifts it’s blood volume to the LV right after the PVR increases. Always appreciate the contributions!

Thanks for the kind words. This is a difficult concept and the exact details remain a touch elusive. We think the best way to understand it is by thinking about the intrathoracic aorta versus the extrathoracic aorta. PEEP increases intrathoracic pressure and as such the difference between the pressure in the thoracic space and the pressure inside the aorta decreases. This is in contrast to the negative inspiratory force required to take a spontaneous breath, which decreases the intrathoracic pressure and subsequently increases the difference in the pressure between the thoracic space and the pressure inside the aorta. Now, if we pull in the extrathoracic aorta we can see that the extrathoracic aorta isn’t affected by PEEP changes. It’s pressure stays the same. When PEEP is applied though and the intrathoracic pressure increases and the transmural pressure then decreases, it is easier for blood to flow down the pressure gradient to the extrathoracic aorta. Compare this conceptually to when we take a spontaneous breath and create negative intrathoracic pressure that “pulls” on the aortic wall increasing the transmural pressure and thus there is less total force to “push” blood downstream into the extrathoracic aorta. Does that make sense or did we just make it more confusing?

Money: It’s all about filthy lucre sake which is why I got out of the medical mafia in the 1990s with a stellar education from UIC ‘83 Biology & Nutritive Sciences + an RD. The ICU is one of the most lucrative units in a hospital which is why although usually only 10% of the overall capacity of a hospital?,it’s run between 85 and 90% constantly occupied rate.

That is a great question! Unfortunately, like many things in critical care medicine there isn’t a single straightforward answer. It is very much dependent on the state of the heart before going on mechanical ventilation (does the patient have heart failure?) as well as the current pathology they have. In some situations it can increase cardiac output and in other cases (probably the majority of cases) it can decrease cardiac output

Thanks for checking it out! It’s honestly an interesting consideration. It reminds me of some early pictures out of Italy I believe that essentially had patients upper torso/head in a bubble that provided both titratable FiO2 and positive pressure. Hadn’t heard of anything like that in the states

@@WhiteboardMedicine That is the cool European helmet CPAP...we need to get this variant here. More comfortable for the patient...saw a sad video with an Italian critical care doc. He said their health system couldn't afford oxygen for high flow so they used CPAP with their helmut systems...they had no negative pressure rooms, but their hospitals are old palaces, and " don't laugh at me, but we opened the windows and got good air flow. "

@@davidmbeckmann Yeah those looked much more comfortable than the often poorly tolerated BiPAP/CPAP masks! All sorts of creative (possible) solutions to limited resources in a time of need. Much cheaper than those negative pressure ventilation systems, to be sure...

Thanks for checking out the video! We use a fairly simple setup using a Wacom Tablet and Microsoft OneNote with Quickly screen capture!