Do you perform spontaneous breathing trials on higher levels of PEEP with extubation to positive pressure ventilation in patients intubated for obesity hypoventilation syndrome?

Yes. But like anything patient selection is key and the rationale for the use of higher levels of PEEP (e.g. improve oxygenation vs prevention of atelectasis for simplicity sake) factors into the decision (as do co-morbidities -heart failure, pulm HTN, etc). 

The literature nor weaning guideline do not really designate an acceptable range of PEEP for SBT though the safety screen suggests <8 cm H20 but again is predominantly based on PEEP for oxygenation as opposed to setting PEEP to mitigation of atelectasis and maintaining some FRC. While the best SBT to mimic the work of breathing post-extubation remains a t-piece or "flow-by" trial (PS 0 PEEP 0), drastically reducing a PEEP from 15 to 5 for the sake of an SBT can precipitate large inspiratory pressure swings as well as atelectasis leading to weaning failure.

We have started an ongoing case series tracking these high PEEP extubation at one of our hospitals for our morbidly obese patients.(BMI >50) comparing high PEEP extubation (~10+ cm H20) to that low PEEP (<10 H20) We often will utilize esophageal manometry to set the PEEP setting the Transpulmonary PEEP 0 to -2 cm H2O (with titration based on patients evolving condition). SBT was then employed with PS ~5 above the set PEEP with success (and safety). Most if not all patients were extubated to noninvasive (using established PEEP as a guide for EPAP/CPAP). While the N is low, we are seeing reductions in vent days as well as reintubation with extubation on the higher PEEP. Granted this is all but an anecdote at this time.

I typically do a regular spontaneous breathing trial with PEEP 5 and PS 5 because I don't want to distort the patient physiology during the trial (I want to know as close as possible what they would do if they were extubated). However, I do extubate to PAP much like COPD or heart failure. Increased PEEP would potentially artificially inflate oxygenation during the SBT. It would also decrease preload (and afterload), which can have substantial hemodynamics particularly if they have right heart failure.