Praetorian said:
I was in Kindergarten so I'm just going off what I was told.....
Well, I was there at the time as a surgical intern. So called super peep was advocated by a series of Anesthesia intensivists at Wilford Hall (the big AF hospital) and Shands in the 70s. It required a patient with generalized ARDS and problems with oxygenating with FiO2 of >0.5 and conventional PEEP pressures. These patients are thankfully, relatively uncommon. They have very stiff lungs in which the airway pressures are not transmitted to pleura or right atrium.
It was carefully controlled and depended on taking matched Arterial and Pulmonary artery samples every hour to measure the shunt fraction. One then adjusted the PEEP about 3 mmHg an hour up or down, until the magic level where the shunt fraction dropped and the hypoxia cleared. It was important the the patient be on IMV rather than Assist-control so that the patient had a chance to decrease intrathoracic pressure to negative compared to atmmosphere, thus creating a pressure gradient for blood return to the heart. You had to continue to do the sampling hourly, for when the patient improved, the required PEEP went down and the high pressures were then transmitted to the pleural space and the right atrium.
Findings:
1. We could oxygenate anybody.
2.Incidence of barotrauma and hypotension were the same as anybody else's results, and this was a sicker subset of patients.
3. ECMO avoided, a good thing, since I don't think it was widely available, and I believe it was abandoned in adults as ineffective.
The point of this rant is that superPEEP worked well in the hands of careful people who could follow protocols. I'm not an intensivist, there may be better ways to handle such a patient today, but most of the bad results were from people who didn't follow the rules, sort of like tPA for stroke.
😉