When to wean the CPAP in SCAPE

Source: http://emcrit.org/blogpost/when-to-wean-cpap-scape/
SCAPE= Sympathetic Crashing Acute Pulmonary Edema

Gabe writes:

REMCS notification of an obese female in her 50s being brought in on CPAP for resp distress, history of CHF, tachypneic and tachycardic.
Immediate page for respiratory to bring down NIV.
When she came through the ambulance bay, I categorized her immediately (thanks to your podacst): SCAPE. Tachycardic, hypertensive, tachypneic, diaphoretic, and severely agitated saturating upper 80s with crackles to her apices. With intubation gear ready, I placed her on a PEEP of 8 and dropped at SL NTG 0.4mg under her tongue (couldn’t get the IV nitro in time) and gave 50mcg fentanyl.
2 minutes later: RR 24 (from 40s), sat 100%, HR 80s, dry skin, and talking to us behind the CPAP. My attending was so proud and, quite frankly, relieved at not having to intubate an impossible airway.
My question is: once the patient has stabilized on the NIV, do we wean it down? Switch to NRB? Leave it to the CCU?
Thanks!

Gabe, Great question!
Here is how I wean the CPAP on these folks:

• The patient must look good–I mean really good before I’ll even think of turning the dial. No diaphoresis, no labored breathing, can talk to you easily under the mask.
• The blood pressure must have dropped to the patient’s norm or what you think is the patient’s norm.
• The nitro drip must have done its precipitous drop thing, by which I mean, at some point these SCAPE patients turn off their sympathetic surge. Their nitro drip necessity will go from a level such as 180 mcg/min to 30 mcg/min. Once that happens, you know you are over the hump.
• When all of the above have occurred, I drop the fiO2 to 40% and then I start weaning down the PEEP setting about 2 cmH20 every 5-10 minutes.
• Check the patient for the above before each subsequent PEEP drop.
• When they are at 5 cmH20, give them a trial of nasal cannula.
• Keep the entire CPAP set-up ready at the bedside
• If the patient’s BP spikes or they get sweaty and are having trouble breathing, put them back on CPAP and go back up on your nitro.
• Now is the time to assess whether you think they are volume overloaded and if you think it is clever, give them a diuretic. For me I’d rather they get their kidneys going with the nitro instead of the diuretic.