Clinical Pearls: Is It Time To Extubate, An Objective Approach
I spent a lot of years working at the bedside in the ICU. I can tell you one thing a nurse won’t tolerate and that’s an agitated and intubated patient. IYKYK. It’s scary, it’s physically taxing for you, and it’s not good for the patient. So naturally I would immediately call the provider with the “can we extubate” query when they woke up fighting. In my mind they were awake, right? Let’s liberate them from the ventilator!
This is only one scenario in which the clarity I gained in NP school blew my mind at how naive I was as a nurse. Maybe naive isn’t the right word, uninformed perhaps? IDK, I think my point is I didn’t realize there was a systematic approach to assessing extubation readiness. I didn’t properly think through all the reasons why a person would need a vent, nor appreciate all the ways in which a person can fail an extubation attempt. One key factor I learned is that objective medical analysis of the diagnosis and current exam is crucial in predicting risk and then weighing the risk/benefit ratio to determine what is safest for the patient. In this post I’ll walk you through the step by step process of performing this assessment to eliminate as much doubt as possible and set your patient up for success. Skip to the end for a bedside checklist.
Step 1: Is the primary problem corrected or adequately improved?
Why were they intubated?
You NEED to have a reasonably good explanation (aka diagnosis) for what necessitated the ETT in the beginning. If you don’t know what’s wrong how can you expect to know when they are better?
Some problems are quickly corrected, and the most common of these is a neuro status change that rapidly corrects (ahem, looking at you overdose). Once the neuro issue is resolved - THIS would be the patient who you can most likely extubate with success once they wake up. Other quick turnaround examples: pulmonary edema that just needs a good dose of lasix; elective procedures requiring a secure airway.
Of the problems that do not correct quickly (pneumonia, alcohol withdrawal needing heavy sedation for awhile, sepsis) there is generally a multi-factorial contribution. Like the failure to thrive late stage dementia patient who is aspirating and developed pneumonia. Or the bacteremic pt whose kidneys failed and now thay have volume overload issues. You are gonna need to have a clearer plan if the issues aren’t improving as expected. And if the pneumonia is still a prominant factor in a patient with poor ability to clear their airway (because of weakness, terminal disease, or just copious secretions) you can’t just pull the tube and hope it works out.
Is this problem resolved?
If the initial diagnosis is not corrected, how will extubating them set them up for potential failure? Think through all possible outcomes.
If it is not resolved or even reasonably resolved, you have three options.
Discuss tracheostomy.
Discuss diagnosis/prognosis with the family and determine goals of care. It may be that this person was ill before intubation and told people to only give it a week to see if it got better but then no more. It may be that this person is not improving or worsening with poor odds for recovery.
Give them more time. There is no set timeframe. Pre-covid we felt pretty good limiting our timeline to correct things to about 7-14 days. There is some decent evidence to suggest that the risk of vocal cord damage and ventilator associated pneumonia rises after a week. In practice though, we left people on the vent for week(s) during covid without the high amount of complications to the degree we expected. Obviously, the longer it stays in the worse the risk. But how much time 🤷🏼♀️? I think that boils down to diagnosis, pre-hospital health of the patient and their ability to recover, and family dynamics. If the family is adamantly against trach, we tend to stretch the time on the OETT longer.
What is the risk if it not entirely resolved?
There are patients who are quite grey in regards to problem resolution. It’s not an exact science. Sometimes you give them a trial extubation with a solid plan for the event of failure.
Are they a difficult airway? Do they want re-intubation or not? Are they ok with a tracheostomy?
Step 2: What is the neuro status?
Start with a GCS and always account for the amount of sedation you have them on.
Do they understand you and follow commands?
I never ask a patient to squeeze my hand. It’s too subjective an assessment and too many confounders to reliably use this. Instead ask them to stick their tongue out. With exception for the pt with tongue edema this is easy for them to do and yes, you can see them attempt even with the OETT in place. Or, try asking them to look a certain direction.
Step 3: What are the pulmonary mechanics?
Vent settings currently
FiO2 should be low ~ 30
Are they having any apnea?
Do they have a metabolic alkalosis? This is a primary reason your patient has apnea or bradypnea. The body’s natural compensation for this ABG derangement is respiratory acidosis (aka breathe less).
Are they still on sedatives? Even Precedex. Even just prns. Even atypicals like gabapentin, seroquel…
What does the CXR look like? Now, take this with a grain of salt. Xrays lag behind clinical improvement. But in general, if you open it up to see white out - you’re not likely to want to extubate right then you know. Look at trends, account for what the diagnosis is and generally accepted timelines for things to clear up. You don’t need a pristine set of lungs, but it really should be looking better than when you started.
ABG? Whoa hot topic if you know me at all. I don’t love the weight people place on ABG results. Most things can be ascertained by a good clinical exam. Are ABGs helpful in making this call? Possibly. Consider the AECOPD pt and you really want to see that CO2 level coming down. Well, you may not if they live with chronic hyeprcarbia. But you can see if the acidosis is correcting. You also can do a good exam to determine if the CO2 narcosis is wearing off. If they are awake, communicating appropriately and changing the channel on the remote do you really need an ABG to confirm that pH went from 7.30 to 7.35? Maybe, maybe not. As far as hypoxia - unless the pt has massive shock or a poor SPO2 waveform - just look at the monitor.
CPAP or SBT trial - when performed and how they responded
First look at how much pressure support is being applied. The patient failing a trial on minimal PS is less concerning than the patient on a lot of support still. An adequate trial for most people would be a PS and PEEP of 5 or so.
A heart failure patient at risk of flash pulmonary edema on the other hand. This is a scary patient. Think: the one with an EF of 15% who has an XR full of vascular congestion. This one, when you take the positive pressure away has very high risk of flash pulmonary edema. Why? Well a sick heart can’t handle much preload - which is why we diurese them. When you intubate this patient you apply positive pressure and this “squishes” the IVC and therefore reduces pre-load, which makes it easier for the heart to unload the lungs and therefore - easier to breathe. Thus the inverse of this is true when you take the tube out. The takaway - reduce the amount of support the vent is providing as much as humanly possibly and see how they do on their trial. Do they become diaphoretic, tachypneic, high work of breathing, tachycardic? This patient is not doing well. My theory is - give a short (15-30min max); very aggressive PS trial to these people. Zero PS, Zero PEEP - aka ZEEP. Yes, it’ll be a challenge. If their heart can handle them sucking wind for this long and do ok - they can handle extubation.
Secondly, look at the Rapid Shallow Breathing Index (RSBI). This is the RR/TV, and it should be well under 100. The higher the number the worse they are tolerating the trial. The physiology is such: in a state of physical stress (pulmonary pathology like ARDS with poor compliance, pulmonary edema, pneumonia, etc or deconditioning like failure to thrive or you name it but basically any physical reason) it is easier to breathe fast and shallow than slow and deep. As opposed to anxiety in which we breathe fast and deep.
How are they hemodynamically handling the trial? Too much tachycardia/HTN is concerning. Yes agitation; suddenly being off of sedation infusions can contribute but if anxiety is the sole cause you should be able to talk them down and see an improvement at least temporarily.
Are they maintaining their saturations on the low settings while on the trial?
Step 4: What are the functional mechanics?
This is where you want to make sure they have the strength to maintain their airway and clear secretions. It’s a pretty straight forward assessment.
Can they cough and is it robust? If they have a pneumonia, especially a heavy secretion producing one like MRSA, ensure they have a good cough.
Can they take a deep breath on command. As them to do so and then look at the TV. You want it larger than the baseline TV. If they are on CPAP + PS 5 and their avg TV is 400, they should be able to pull something like >650ish on the low end.
If this is a pt with functional debility (critical illness polyneuropathy, failure to thrive, Guillan Barre, Myasthenia Crisis, chest wall issues that restrict muscle movement, abd compartment syndrome, etc. ) who is awake and following commands check a Negative Inspiratory Force (NIF) value which assess their ability to inhale +/- an ABG to assess their CO2 clearance (can also just trend the end tidal).
Step 5: Is there a cuff leak and does it matter?
Ask the RT to check for the presence of a cuff leak. Or do it yourself. Deflate the air from the pilot balloon and listen for air or phonation. This indicates airway edema is not present. The problem is that this test while specific lacks sensitivity. Meaning, if there is an air leak: ✔️ they passed the test. But if there is not an air leak it could mean a number of things and airway edema is just one of those things.
If they fail the air leak test, first do some trouble shooting.
Is the cuff truly deflated? Make sure the bite block has not slid down over top of the pilot balloon line. If it is occluded this could cause the pilot balloon to be flat indicating a deflated cuff but in reality it is still up.
Get a CXR. Is the tube in correct position? Is there a misplaced gastric tube?
Is this a big tube in a small person? The diameter of the tube itself could just be abutting the airway walls.
Consider laryngoscopy to look in the oropharynx and airway.
Consider a CT of the neck if there is a known issue of malignancy, infection, or swelling.
Then either add some steroids for a day and recheck or consider if you think this is a non critical issue and just trial extubate anyways.
Step 6: Any pending surgeries/procedures?
Goes without saying but if there is anything coming up soon that requires a secure airway go ahead and take care of that first.
Consider some non-obvious tasks like MRI, TEE, EGD. Basically anything that would require conscious sedation.
Step 6: What’s your failure plan?
Lastly, talk with the decision makers about steps to take in the event of failure. Would this person want to be re-intubated or is this it and we proceed to comfort measures only if they fail? Also bring up the idea of tracheostomy.
Assess the difficulty of intubation so you know your approach in the event they require re-intubation.
If you have a zero % fail rate, you aren't attempting enough
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If you have a zero % fail rate, you aren't attempting enough 〰️
Quick Checklist
Primary problem resolved or significantly improved
No pending procedures/surgeries
Neuro check
Look at vent settings while on an SAT/SBT trial
Minimal to no sedation
PS sufficiently low which ranges, but avg <5
FiO2 <30
PEEP 5
RSBI <100
No apnea alarm. RR is sufficient, at least >12
Look at the monitor
HR good for them. On avg <100
RR <24ish
BP stable
SPO2 (account for the primary problem) but in general >94ish
Ask them to lift their head off the pillow
Ask them to take a big deep breath
Alternatively, check a NIF or ABG
Ask them to cough
Check the secretions (consistency/amount)
Assess for the presence of a cuff leak
Establish re-intubation plan vs GOC
Liberate
#LIBERATE