Clinical Case 004 – Post-op PEEP++

This case happened today and I think it is in my top 3 ventilation challenges ever!

19 yo man, fit and well, thin.  Acute appendicitis, not particularly septic pre-op.  Underwent routine RSI and  open appendectomy (necrotic appendix, no free fluid).  muscle relaxants reversed and extubated without incident and moved to Recovery room.   About 10 minutes later was noted to make a long ” groaning noise” and rapidly became hypoxic.  Commenced BMV by GP anaesthetist – easy to bag – SpO2 low – 60 – 70%, no improvement after a few minutes, lung sounds “wet” bilaterally.  I came in at this point as a second pair of ands – we decided to return to OT and reintubate.  Working diagnosis at this point was “negative-pressure pulmonary oedema” following a probable episode of laryngeal spasm (possibly aspiration-induced).

Patient was re-intubated and sedated.  Commenced on Vol conrol with PEEP 10 cm, SpO2 improved to 90% on FiO2 98%.  POrtable CXR = diffuse, bilateral ‘fluffy’ perihilar infiltrates.  Small right upper lobe consolidation.

At this point we decided to keep going with PEEP and plan to attempt to wean it down over the next hour or so if possible, given frusemide and art. line inserted.

ABG – pH 7.22, pCO2 – 66, pO2 – 60,  on 100%.  At this point it became clear we were dealing with serious lung injury.  Patient coughed and pink frothy sputum coming up the ETT.  SpO2 started to decline over the next few minutes.  We re-paralysed and took control of the ventilation.  The plan:  set a smallish Vt (6ml/kg), high RR to ventilate and bring CO2 down,  increase PEEP with intermittent prolonged PEEP “recruitment” manual bags.  This was effective and the SpO2 came up again to 95%.  However over the next few hours the patient became increasingly hypoxic.  Airway pressures were rising, repeat CXR showed worsening infiltrates, no pneumothorax.

By sundown we were running PEEP at 18 cm, RR – 22/min, Vt = 425mls.  BP started to drop, we put in a CVC and started some Norad – central pressure and IVC index suggested patient was well loaded, reasonable urine output.  We were not keen to increase PEEP further and the hypoxia once again increased – Sp)2 consistently 84%.   What to do…?  We needed to get this guy onto the Oxylog 3000 at some point also as the RFDS were incoming to fly south.  One attempt to change ventilators resulted in worsening hypoxia.   So…..

We decided to roll the patient – tried right (worse) side down – SPO2 much worse -75%.  So we tried right-side up – bingo, good improvement over 10 minutes = SpO2 up to 94%, We were able to start winding back the PEEP and successfully changed to the Oxylog.  2 hours later we were back to 10 cm PEEP and FiO2 of 0.50 on the Oxylog – the retrieval team were happy.  Patient was transferred south and extubated the next morning.

I would love to hear your experiences with this type of case, what would you do differently?

Check out the links below to some great resources for the tricky-to-ventilate cases:

From EMCrit this simple 2-strategy approach to ventilating the difficult lungs

Another paper looking at a few cases with references:

Another case discussion paper,

As you can see apart from case reports there is not a lot of “evidence” as to how to manage this phenomenom “NPPO”.

My reading of it is basically:  diagnosis is pretty much clinical with a good history of upper airway obstruction leading to rapid “wet lung”, you need to rule out other potentials – APO (cardiac), aspiration, PE, maybe fulminant pneumonia or tamponade??  Sometimes it is unilateral – esp. if the tube went endobronchial (doh!)  Early management includes oxygen, ventilation using PEEP and consider the differentials.  Lasix might help, but no evidence really… thinking outside the box, as a keen altitude trekker – would dexamethasone or Ca-cannel blocker help – they are used for HAPE in the Himalayas??  Watch this space..



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