High Flow Nasal Cannulas

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urge

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Educate me on the use of this device versus non invasive ventilation when used to prevent (re)intubation for patients in respiratory distress.

Any success stories? Any failures?

How much flow is in a Bipap?

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A recent RCT suggests that, post-extubation, HFNC can decrease the rate of reintubations significantly even in healthy patients, when compared to regular nasal cannula. The advantage of HFNC over BiPAP is higher comfort levels (allows eating, speaking, coughing, no mask injury), better compliance, better secretion evacuation (it also humidifies them), while possibly decreasing dead space.

AFAIK, the same can't be said pre-intubation, although it can buy enough time in selected cases. Its PEEP level is in the 5-6 com H2O magnitude, even at high flows, so BiPAP is better for hypercarbia or CHF patients, or whenever you need more pressure support. Generally I use NIV in either form as long as I (fore)see significant improvement in the short-term. It can work beautifully in selected patients who would have increased complications if intubated (immunodeficiency, chronic severe lung disease etc.), provided that the factors leading to hypoxia/hypercarbia are aggressively treated. If it doesn't work in 24-48 hours, I intubate.

I never pay attention to the BiPAP flow rate, only to IPAP/EPAP.
 
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A recent RCT suggests that, post-extubation, HFNC can decrease the rate of reintubations significantly even in healthy patients, when compared to regular nasal cannula. The advantage of HFNC over BiPAP is higher comfort levels (allows eating, speaking, coughing, no mask injury), better compliance, better secretion evacuation (it also humidifies them), while possibly decreasing dead space.

AFAIK, the same can't be said pre-intubation, although it can buy enough time in selected cases. Its PEEP level is in the 5-6 com H2O magnitude, even at high flows, so BiPAP is better for hypercarbia or CHF patients, or whenever you need more pressure support. Generally I use NIV in either form as long as I (fore)see significant improvement in the short-term. It can work beautifully in selected patients who would have increased complications if intubated (immunodeficiency, chronic severe lung disease etc.), provided that the factors leading to hypoxia/hypercarbia are aggressively treated. If it doesn't work in 24-48 hours, I intubate.

I never pay attention to the BiPAP flow rate, only to IPAP/EPAP.
I knew you would have done input on this.

What's the physiology behind the high flow? Increased tidal volumes?
 
I knew you would have done input on this.

What's the physiology behind the high flow? Increased tidal volumes?
Dead space washout. Basically the same effect as increased tidal volumes, but without lung distension and barotrauma.
 
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Dead space washout. Basically the same effect as increased tidal volumes, but without lung distension and barotrauma.
There is a nice review article in Chest for those who have access.

http://www.ncbi.nlm.nih.gov/pubmed/25742321

I have to say I'm a little underwhelmed after reading it. There is a lot of hoopla about them where I'm at but after reading the review it doesn't seem so great.
 
seems to get some folks through without intubation, better tolerated than cpap masks

There is some literature around that shows they work great for apneic oxygenation ... Though I haven't tried that out
 
Use it very frequently, it will give you another 12-36 hours to get whatever it truly behind the oxygenation issue to be treated. I like it because it is better tolerated by the patients than face mask CPAP and you can continue to use the high flows with low Fio2, i.e. if you want a little peep put the NC at 50 l/min but an Fio2 of 35 or 40%. I have averted intubations many times with this maneuver. One draw back that i have seen is bowel dilation in the high gas flows but i dont think any different risk that traditional CPAP/BiPAP.
 
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