Cpap

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noisyone

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I'm a student currently pursuing my EMT certification in Kansas. I was hoping someone could help me understand CPAP a little better, and when it's appropriate to use it.

Please correct me where I might be mistaken. Here is my understanding so far.....

When a patient is in mild respiratory distress, and needs a small amount of O2, we would use a nasal canula set to about 2-6 lpm.

When a patient is in moderate distress, but breathing on their own, we use a non rebreather mask set to about 10-15 lpm.

When a patient is not breathing on their own, or if the breathing is inadequate, we use a BVM.

Where does CPAP come in? Our teacher made it seem like CPAP is great, but I don't really understand what the criteria is for using it.

Thanks in advance.
 
How about if the patient is breathing on their own, but the breaths are too slow or too shallow to provide proper perfusion? You osculate the lung quadrants, and the lower lobes present diminished breathing sounds..

How about a patient with COPD who has pulmonary edema?
 
Household6 said:
How about if the patient is breathing on their own, but the breaths are too slow or too shallow to provide proper perfusion? You osculate the lung quadrants, and the lower lobes present diminished breathing sounds..

How about a patient with COPD who has pulmonary edema?
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May want to auscultate the lung fields first haha...

Think about what sort of disease processes prevent the patient's airway from remaining "open" (for a simpler term). In many cases a BVM could be used in the same manner, but it is far more difficult to do so.
 
BVMs, are awesome, but lets say you're working the ER and a patient needs breathing assist. There's no way you want to stand at their bedside for the next 6 hours squeezing a bag, right?
 
CPAP is used primarily in cases of pulmonary edema and COPD, coupled with nebulized medication. It's NOT a replacement for a vent or BVM. The patient has to be conscious and able to maintain his own airway. It reduces work of breathing and may prevent intubation.
 
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This is all good information. Thanks to everyone that has posted so far.
 
First, consider the role of the pressure generated by CPAP and not the flow used to create it, because these are often confused. Consider individual alveoli as being bunches of balloons. We all know from personal experience that the hardest part of the balloon is getting them open at the very beginning. Same for lungs...when babies take their first breath alveoli are collapsed, however they are coated with a liquid called surfactant, which prevents them from fully collapsing at end exhalation. Surfactant is one of the last substances to develop in utero, and this is why preemies can have such a hard time breathing (and are placed on CPAP until they develop their own surfactant or have some instilled).

Looking at a case of congestive heart failure, the fluid entering into the lungs washes out the surfactant leading to the collapse of the alveoli. Having them open and close with each breath or having some segments open and neighbouring ones collapsed can tear them apart from shear stresses (ARDS). So, the role of CPAP is to apply additional pressure above ambient to re-recruit those alveoli and prevent them from collapsing again on every respiratory I:E cycle. Once they are recruited, the work of breathing decreases and breathing becomes easier, often lessening the need for supplemental % oxygen. This is why its only for spontaneously breathing patients, but its only a stop gap solution until the initial problem is fixed with nitrates, diuretics, etc

Another common way of describing CPAP is a "pneumatic stent" to maintain patency of the alveoli. This also works for snoring, to maintain the soft palate in the upper airway instead.
 
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I was going to say it helps recruit alveoli and "splints" the airways open to put it simply then ThadeusJ came in for the mf'in win!
 
Or as my good alter ego Dr Gofast says, your lungs depend on the outside air pressure to rush in and inflate your lungs as your diaphragm makes room for more air. The CPAP increases that ambient pressure, but only under the mask and into your airways.

And surfactant, like some firefighting agents to make "wetter water", breaks down the surface tension and molecular attraction in the normal fluid in the alveoli so those fluids don't make it harder for the alveolar walls to let go of each other and admit air. Like the opposite of spitting on a suction cup to make it stick better.
 
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DEmedic said:
CPAP is used primarily in cases of pulmonary edema and COPD, coupled with nebulized medication. It's NOT a replacement for a vent or BVM. The patient has to be conscious and able to maintain his own airway. It reduces work of breathing and may prevent intubation.
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I'd argue that, as you noted, it's carved out a nice little chunk of patients who would have otherwise been intubated in anticipation of them crashing due to increased work of breathing.
 
Household6 said:
BVMs, are awesome, but lets say you're working the ER and a patient needs breathing assist. There's no way you want to stand at their bedside for the next 6 hours squeezing a bag, right?
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We'll take the PVC challenge.
 
Tigger said:
May want to auscultate the lung fields first haha...



Think about what sort of disease processes prevent the patient's airway from remaining "open" (for a simpler term). In many cases a BVM could be used in the same manner, but it is far more difficult to do so.
Click to expand...


I don't know of many providers able manipulate a BVM to provide the CONSTANT positive pressures seen with CPAP. :)
 
DEmedic said:
I don't know of many providers able manipulate a BVM to provide the CONSTANT positive pressures seen with CPAP. :)
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Which it's why it's such a lovely improvement! Bagging a COPD exacerbation isn't particularly effective.
 
Intermittent positive pressure (inhalation augmentation such as synchronized BVM) ought to still do a bit of good. If there is a constant pressure gradient higher than that of the exhalation, then the spent air will not leave the lungs, requiring increased exhalation pressure…which describes COPD all over again.

Actually if you took an elastic reservoir with similar valve setup to a BVM but selectively restrict the outlet to control outlet pressure you could pump into it at will, within some limits and get a constant tunable outflow.

Oh, that's been invented too! Without the valves no less.
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DEmedic said:
I don't know of many providers able manipulate a BVM to provide the CONSTANT positive pressures seen with CPAP. :)
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Well that's for 2 reasons:

1. BVM's do not provide constant O2 flow on the patient side (however, Mapleson bag circuits do).

2. Most BVM's do not come with PEEP valves.

I just don't see the harm in a trial of CPAP even when the patient is obtunded. Especially if they are sat upright and low PEEP is used. If they've got spontaneous respirations it'll likely work better than us fighting them with a bag. A bag which'll let them rebreathe if we're not squeezing...a bag which delivers far higher pressures.
 
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Christopher said:
Well that's for 2 reasons:

1. BVM's do not provide constant O2 flow on the patient side (however, Mapleson bag circuits do).

2. Most BVM's do not come with PEEP valves.

I just don't see the harm in a trial of CPAP even when the patient is obtunded. Especially if they are sat upright and low PEEP is used. If they've got spontaneous respirations it'll likely work better than us fighting them with a bag. A bag which'll let them rebreathe if we're not squeezing...a bag which delivers far higher pressures.
Click to expand...



I was being facetious. :)
 
There is a great CE video at the Bound Tree Medical CE site on CPAP. Check it out.
 
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