Fatties and anesthesia

[Iso4ane]

I'm surprised that this isn't taught more - my residents never understand this either.

I always use 1:1 or 1:1.5 to get more volume for less pressure in patients without lung disease.

I've never seen an upsloping CO2 curve in a normal-lung patient I don't think.

My bet is it has to do with medical schools' basic teaching of ventilation. It's oversimplified to PEEP/FiO2 for oxygenation and Vt/RR for ventilation. Anatomic shunting, dead space and V/Q mismatch are "theoretical" concepts that most medical schools do a terrible job of explaining. Heck, most physicians don't truly understand them.

That's interesting. This is something I realized on my own in a round about sense. I think most people should noticed that you decrease the I:E ratio to 1:2.5 or 1:3, the peak pressures increase (which in my head made sense, since you are trying to shove the same amount of air in a shorter period of time; similar to how much force you need to apply to a syringe to administer meds fast vs slow). I had a different patient with normal lungs one day, who had slightly elevated peak pressures, when I thought of the first point, I increased the I:E ratio and fixed that problem.

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[Psai]

That's interesting. This is something I realized on my own in a round about sense. I think most people should noticed that you decrease the I:E ratio to 1:2.5 or 1:3, the peak pressures increase (which in my head made sense, since you are trying to shove the same amount of air in a shorter period of time; similar to how much force you need to apply to a syringe to administer meds fast vs slow). I had a different patient with normal lungs one day, who had slightly elevated peak pressures, when I thought of the first point, I increased the I:E ratio and fixed that problem.

Who cares about peak pressure when plateau is what matters

 

[nimbus]

Who cares about peak pressure when plateau is what matters

They both matter. Alarms are annoying.

 

[Iso4ane]

Who cares about peak pressure when plateau is what matters

True, plateau pressures matter as well, but depending on the anesthetic machine setup, it can be hard to determine to the plateau pressures. On an ICU vent you can just the inspiratory hold button. But, at my program we have three different anesthetic machines, GE Aisys, Avance, and Aespire. You have to know were to look. The closest you can get is by setting the machine in Volume Control and setting a TP%. But, that not is the default mode (nor is it often used around here).