This case is all about the application of tricks and tips I have learned in the last few years from social media, blogs and the wonderful clinicians out there in the ether who form a community of docs with a common goal – doing better for our patients.
A few years ago I would have managed this case very differently. I would have done “standard care”, it would have been a struggle and I would not have been confident. Looking back, I would have given the same care I learned 10 + years ago from teachers, who themselves were also 10 years out of training. I would have been practising the “standard care of 1992!”. Thanks to my mates from the twitter-sphere I was able to apply the type of care that leaders of the critical care world are using today, and be confident that it was a better plan for my patient. OK, onto the case…
84 yo. man with a few chronic problems:-
- chronic AF – on verapamil for rate control, warfarinised – INR currently 4.2. Big left atrium, and hypertrophic LV.
- Severe aortic stenosis: last ECHO was 6 months ago showed an aortic valve area of 0.6cm2! Despite this he had no history of angina, syncope or failure.
- Chronic interstitial lung disease (?asbestos related) – no home oxygen etc, but a lot of fibrosis on the CXR
- Oh, and the CXR showed a significantly displaced trachea! Possibly due to mediastinal fibrosis or the dilated pulmonary vessels?
He presented to ED with a fever, cough and increasing dyspnoea – his AF was faster than we would like. Likely due to a viral LRTI, but he was treated for severe pneumonia with IV abs. After admission he got sicker, tachypnoeic and had a paO2 of 57 on a non rebreather mask.
When I first met this man he was put on NIV for his respiratory ( type 1) failure and he did pretty well. But over the next 12 hours he slowly got tired and intolerant of the mask. His gases started to drift and we were struggling to maintain a good MAP on the settings required to keep him oxygenated.
This is one of the problems with remote critical care: he probably would have done OK with ongoing NIV, but it is along way (2000 km) to ICU if he doesn’t – so we made the call to transfer him before he got any sicker. In an ideal world we would transfer on NIV as it was working ok when he was able to keep it on. But if you are the flight doc you really want a definitive airway in place for transfer – and that mandates intubation and all the risks, morbidity and long slow wean at the other end. From my perspective this is tough, by tubing we are converting a relatively stable situation into a potential disaster scenario. Keeping him is an option, but this might result in a midnight crash call and that is not ideal either. Have you had cases like this?
So how do you plan to incubate and ventilate a hypoxic, CPaP dependent man, with severe AS and a potentially difficult airway? Tricky situations require tricky solutions – so I leaned heavily on the lessons learned from my network of colleagues in the online crit-care world to get it right, keep my anxiety under control and turn a stressful scenario into a controlled and methodical plan. There are many ways to skin a cat – but here are the basic moves we used:
What is this? Well it is using procedural sedation (ketamine) in this case to achieve a relaxed patient who will tolerate a decent crack at NIV for optimal pre-intubation oxygenation and recruitment of as much lung as possible. In this case I gave about 0.5mg/kg about 30 minutes prior to the intubation and had him sitting up with 100% Fio2 via CPAP at 12 cm. For the original DSI blog see Emcrit here
You need to have all your kit at arms reach. We had a standard laryngoscopy set up with a bougie ready to go. Also a video scope at the ready. Intubating LMA was there on the trolly and I had my preferred scalpel / bougie surgical airway gear on my side. You could argue for an awake FO tube up front, but we were happy enough with the airway and CT imaging of the trachea that this was unlikely to be a truly difficult tube.
This is a case where you want a super fast, super smooth intubation. Avoid prolonged looking and rough technique and you can avoid a desat or a BP / HR spike – both bad for this man’s chances. In this case I delegated to my mate and we discussed the plans A and B and C
We used nebulised lignocaine to try and numb up the airway and decrease our induction requirements / avoid a big catecholamine surge. This can be done via the CPAP mask – so no break in the PAP chain.
A balance of ketamine with a smallish dose of propofol was the plan. In this case I split the two into separate syringes. Another 0.5 mg/kg of ketamine, followed by 30 of propofol. Then had the metaraminol and propofol in my hands with eyes on the art line trace. He got a few small boluses of propofol to keep his BP and rate where they needed to be. Minh le Cong tweeted this article
later that afternoon!
I used ~ 1.2mg/kg of rocuronium for a paralytic. Why – well the concept is that sux might make the muscles burn more precious O2. Also this was not a scenario where you could back out and come back later – he needed to fly, so needed a definitive airway. I think if you are giving Roc in ED, you must commit your brain to a surgical airway if required. For a nice 8 minute video on Roc vs. sux see Ruben @ EM updates h
The beauty of using CPAP for preox etc prior to tubing is that you are already using positive pressure, so the haemodynamics are not changing so dramatically. If your patient is using big volume, negative pressure ventilation himself and you then give induction agents and swap to PPV then you have given a double whammy to his cardiac output.
You also have a good idea of the tidal volumes, rates and presures that the patient is likely to require. So you can set up your vent with a pretty good guess as to what rate etc you need. In this case we went with ~ 6ml/kg at a rate of 25 /min, PEEP of 10cm. And it was good – his CO2 and Spo2 didn’t really move.
The plan was to leave the CPAP mask on as long as we could, even use it after the induction agents were taking effect. Then use high flow nasal cannula O2 (15 l/min) to maintain passive oxygen delivery during the 45 seconds between removing the mask and getting the ETT in place. You need to have a nurse ready to go with the cannulae so you can get them on ASAP once the mask is off. If you are doing this then cricoid pressure might help avoid blowing up the stomach with air.
The article that described apneic oxygenation by Weingart and Levitan was legendary before it even hit the press thanks to social media in crit care circles!
Getting the patient into the ideal ramped position is vital to getting the tube in smooth and quick. In order to do this though you need to have the team ready, pillows in place and keep the patient upright as long as possible. Once they are asleep, you can lay them back onto the strategically placed pillows etc. This requires a bit of creative visualisation of how it will look once the patient moves from upright to 30 degress.
So – how did it all go?
Very well. The tube went in first pass. The arterial line trace did not budge. The sats dropped to 96% for about 20 seconds before climbing back up to 99%.
Thanks to all the folks out there who offer all this free advice, knowledge and support for those of us on the frontline. My job just keeps getting easier and easier!