Give Me (Vent) Liberty or Give Me Death

What is an SBT and how we do them

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  • Spontaneous Breathing Trials: Spontaneous breathing trials assess the patients ability to breathe while receiving no vent support. A collective task force in 2001 stated you should start weaning by assessing if underlying cause of respiratory failure has been resolved or not

    • Strategy - T-piece (pictured to right) vs CPAP vs PS

    • Time - at least 30 minutes or no longer than 120

    • Pass/Fail

An international consensus was done which stated several minimum conditions for criteria to perform SBT, but no formal recommendations made on how to do a SBT

  • Strategy -

    • no current evidence that one approach is superior. A Cochran review was done showing no difference between T-piece and pressure support regarding extubation failure but had low quality; but pressure support was found to be superior in the proportion of patients considered to have simple weaning

  • Time -

    • collective task force in 2001; there is some evidence regarding the harmful effects of respiratory muscle fatigue if it occurs early in SBTs

  • Judgement -

    • there is no consensus on what is success or failure, but low heart rate, good blood pressure, no anxiety, low RR is used to “pass”

    • Can patient protect airway? Handling secretions well, not too thick?

    • NIF = important in NM disease; otherwise should be a factor but no the deciding factor

    • Each hospital has their own protocols


Weaning Predictors

But make sure your reintubation rate isn’t too low

  • Too low? not being agressive enough, patients are spending longer on the vent = high risk of badness

  • Too high? Being too agressive

  • Generally shoot for 10-15%

BiPAP or HFNC after Extubation

  • Reconnect trial:

    • Giving patients a period of rest following a SBT would lead to higher success rate

  • Bipap after extubation - has been studied for a very long time

  • blue journal, lancent, ccm, anethesia journals

  • HFNC after extubation

    • Maggiore - HFNC vs Venturi Mask after extubation

    • Hernandez - Effect of HFNC vs NIV on extubation failure


  • Being on the vent is bad; patient should be reasonably safe for SBT

  • You should do SBT/SAT on safe patients every day (wake up and breathe trial)

  • One of the most important weaning predictors is RSBI (f/Vt) - <105 has been show to have a reduced reintubation rate

  • Always think about why you intubated a patient in the first place before you extubate; and think about expected clinical course

  • For high risk patients, consider a period of rest after SBT, HFNC or BiPAP post-extubation

  • Track your reintubation rate - it shouldn’t be too high or too low


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