Proper BVM technique

[JJR512]

My instructor says that the ideal BVM rate is 12 bpm, and since 60 seconds divided by 12 is 5, you squeeze the bag and release, count to five, and repeat.

It seems to me that this is putting five seconds between squeezes, but because the squeeze and release isn't instant, you're really spending more time on each cycle than five seconds. If it takes you two seconds to squeeze and release, then you count to five, that's actually seven seconds per cycle, which only gives you about 8.5 bpm.

I asked my instructor about this, and he said five seconds between squeezes is correct, and it was changed to this in 2005. I'm not sure what he means by "it was changed to this", if he's referring to state protocol, national guidelines, or what.

So I want to know if this is actually correct. It doesn't make much sense to me. I don't know what the clinical significance is between 8.5 and 12 bpm, so I don't even know how much it really matters. But I don't see why we shouldn't start counting to 5 at the same instant we start squeezing. We'd get done releasing the bag sometime between 2 and 3 in the count, I think, then we keep going to five, and start counting and squeezing again. That should give a true 12 bpm.

So what's the correct technique, and any other tips you can provide would be appreciated. I know not to squeeze the bag too hard and too fast.

 

[abckidsmom]

Honestly, I'm not sure what the current reccommendation is as to rate of assisted ventilations. I aim for 10-12/minute, by counting in my head "squeeze, 2, realease, 4, 5" I don't really say that out loud, but that's how I keep myself from ventilating too fast or too hard. I intentionally take the whole two seconds to get the chest to rise, and then release. If I catch myself having sped up, I add the 6th second for a while to even things out.

Not really an "official" technique, but it's worked for me.

 

[JJR512]

Honestly, I'm not sure what the current reccommendation is as to rate of assisted ventilations. I aim for 10-12/minute, by counting in my head "squeeze, 2, realease, 4, 5" I don't really say that out loud, but that's how I keep myself from ventilating too fast or too hard. I intentionally take the whole two seconds to get the chest to rise, and then release. If I catch myself having sped up, I add the 6th second for a while to even things out.

Not really an "official" technique, but it's worked for me.

Your counting method sounds great, and I think is probably what I'll aim to use once I'm out in the field. Unless the instructor (or someone else here) is able to give a very good reason for why it should be five seconds in between, for 8.5 bpm.

 

[abckidsmom]

Your counting method sounds great, and I think is probably what I'll aim to use once I'm out in the field. Unless the instructor (or someone else here) is able to give a very good reason for why it should be five seconds in between, for 8.5 bpm.

The expiratory phase is passive, so if you're not allowing enough time for all of the air to escape, you run an extreme risk of barotrauma to the tissues. I find that this count is acceptable to have the chest recoil to the starting position. It will recoil faster if the patient is intubate (less upper airway resistance) and slower in cases of bronchoconstriction (more lower airway resistance).

You just have to be aware, in IRL practice, of how that's looking. Sorry I'm no help in the classroom.

 

[Aidey]

My instructor says that the ideal BVM rate is 12 bpm, and since 60 seconds divided by 12 is 5, you squeeze the bag and release, count to five, and repeat.

It seems to me that this is putting five seconds between squeezes, but because the squeeze and release isn't instant, you're really spending more time on each cycle than five seconds. If it takes you two seconds to squeeze and release, then you count to five, that's actually seven seconds per cycle, which only gives you about 8.5 bpm.

I asked my instructor about this, and he said five seconds between squeezes is correct, and it was changed to this in 2005. I'm not sure what he means by "it was changed to this", if he's referring to state protocol, national guidelines, or what.

2005 is when the AHA guidelines changed.

Collectively we as a profession ventilate people way too fast. When I am ventilating a patient on capnography I pay more attention to the numbers than how fast I am ventilating. I always feel like I am ventilating too slow, but the numbers look good, and the capnography tracks breaths per minute, and it usually ends up between 10-14.

So, honestly, count to 5 between squeezes. When you breathe in and out do you only pause for 2 seconds? The next time you count respirations on a patient who isn't in resp distress also count how long they pause between breaths.

 

[JJR512]

I don't know why I didn't think to check the textbook or protocols before asking the question here...

Our textbook is the Brady Emergency Care 11th Edition. On page 147, it says:

Ensure that the rate of [artificial] ventilation is sufficient—approximately 10-12 per minute in adults...

So just based on that, it seems the ~8.5 bpm achieved if putting a full five seconds between baggings is insufficient.

As for the Maryland protocols, I cannot find that it provides a specific rate at which to ventilate with the BVM, but it does say that an indication for using the BVM is "inadequate respiratory rate", which it says is less than 8 for adults. So if <8 is what the protocols considers "inadequate", it doesn't seem that artificially ventilating at a rate of around 8.5 is going to be much of an improvement.

(The Maryland Medical Protocols can be found here, first link in the list, if anyone's actually that interested: http://www.miemss.org/home/EMSProviders/EMSproviderProtocols/tabid/106/Default.aspx)

 

[JJR512]

2005 is when the AHA guidelines changed.

Collectively we as a profession ventilate people way too fast. When I am ventilating a patient on capnography I pay more attention to the numbers than how fast I am ventilating. I always feel like I am ventilating too slow, but the numbers look good, and the capnography tracks breaths per minute, and it usually ends up between 10-14.

So, honestly, count to 5 between squeezes. When you breathe in and out do you only pause for 2 seconds? The next time you count respirations on a patient who isn't in resp distress also count how long they pause between breaths.

Sorry, Aidey, I missed your reply before I started writing my last one.

I know that if I try to wait a full five seconds between when my chest finishes collapsing (end of exhalation) and I start drawing in the next breath, it isn't too many breaths before I start to feel SOB.

Your 10-14 rate sounds fine to me. The 12 that I think we're supposed to be aiming for is smack-dab in the middle of that. My concern is that putting a full five seconds between breaths doesn't really allow for 12, or even 10; it's more like 8 to 8.5.

 

[Aidey]

Here is the problem, counting to 5 is not 5 seconds. I guarantee that if you count to 2 between the end of one breath and the start of the second you will be ventilating the patient too fast.

 

[JJR512]

Here is the problem, counting to 5 is not 5 seconds. I guarantee that if you count to 2 between the end of one breath and the start of the second you will be ventilating the patient too fast.

No, when I say "count to five", yes I'm talking about seconds. Five seconds is specifically what the instructor was saying to count. He even demonstrating: "Squeeze, release, one one thousand, two one thousand, three one thousand, four one thousand, five one thousand, repeat."

So I'm not really interested in getting into an argument over how fast or slow different people count, counting speed in normal vs. stressful situations, or anything like that. Because when I'm talking numbers here, I'm talking seconds, or breaths per minute, or whatever specific measurement I mention along with that number; I'm not talking how fast it takes me, personally, to count to two or to five. I'm talking about how many artificial ventilations per minute do we actually want to deliver with a BVM, regardless of how we count it. That's what's important here.

 

[EMS/LEO505]

We were told to follow our pattern with the bvm. Meaning we breath in and as we do that we squeeze the bag, breath out etc..... Works out good, and actually helps the lot of us with preventing the hurricane of death haha

 

[Aidey]

Aim for 12.

However, how you count is of utmost importance and you should not dismiss methodology. When discussing ventilation you can not ignore the fact that people hyperventilate patients, and it is a serious problem that can have a negative affect on patient outcomes.

http://www.ncbi.nlm.nih.gov/pubmed/17289248

http://circ.ahajournals.org/cgi/content/abstract/01.CIR.0000126594.79136.61v1

 

[JJR512]

We were told to follow our pattern with the bvm. Meaning we breath in and as we do that we squeeze the bag, breath out etc..... Works out good, and actually helps the lot of us with preventing the hurricane of death haha

I was thinking about that method, but while that might work in class, I was worried that in a true stressful situation, I might be breathing faster, thus I might hyperventilate the patient.

Aim for 12.

However, how you count is of utmost importance and you should not dismiss methodology. When discussing ventilation you can not ignore the fact that people hyperventilate patients, and it is a serious problem that can have a negative affect on patient outcomes.

Thanks, the number of bpm to aim for is what I was looking for. I am aware of avoiding hyperventilation. What I was worried about—indeed, it's the very purpose of this thread—was hypoventilation, which it seems is what will happen if we count a full five seconds between each breath. So it seems that if I count using abckidsmom's method, I'll be fine.

 

[emt_irl]

my take on it is and my clinical practice also say once advanced airway is placed ventilate at 8-10 resps per min. which equals to one squeze of the bag every 5 seconds if it takes 2 seconds to squeeze it in and release.

the way i see it is that 1 squeeze of the bvm will deliver 100% o2 in a big volume where as when breathing normally yourself you never truely breath in your entire volume. so 8 resps per min via bvm is better then lets says 12 resps per min at half capacity.

but once the spo2 is above 97% on the monitor and co2 is down, your doing ok.

hope that makes sense?

 

[Veneficus]

Don't foget it is not just an oxygenation issue but an intrathoracic pressure issue too.

An increase in thoracic pressure can be significant enough to collapse coronary arteries.

Easy to see where ventilating a nonperfusing heart could be a problem.

Chances are you will not ventilate too slowly, more likely too fast. In a hybernating state, tissues have a lower matabolic need. Introducing oxygen free radicals can break down cell membranes and permiating o2 into the cell can set of mitochondrial apoptotic cascades which are irreversible.

Less is often more when it comes to ventilation.

Consider BVM with CPR. If you bag at a rate of 12 per minute that reduces effective cardiac perfusion by 12 seconds. It takes approximately 5 compressions to build adequte perfusion pressure. At 100 compressions a minute that is a compression ~ 1.6 seconds. 1.6x5 = 8 so for every pause to vent, you will lose 8 seconds after the vent rebuilding perfusion pressure. If ventilating 2 times for 1 second in a (30/2 role) that is 12 seconds lost to vent. 1/2 that to 6 total pauses per minute 6x8=48 and it is possible to spend an entire minute performing CPR without sufficent perfusion pressure.

I agree, by capno is probably the best way. But all these numbers are not absolute in all people. (it would be much easier if they were)

 

[Smash]

The expiratory phase is passive, so if you're not allowing enough time for all of the air to escape, you run an extreme risk of barotrauma to the tissues. I find that this count is acceptable to have the chest recoil to the starting position. It will recoil faster if the patient is intubate (less upper airway resistance) and slower in cases of bronchoconstriction (more lower airway resistance).

You just have to be aware, in IRL practice, of how that's looking. Sorry I'm no help in the classroom.

An ETI doesn't decrease resistance, it increases it. Recall Poiseuille's Law and consider the length and diameter of the airway you have just created.

 

[JJR512]

Don't foget it is not just an oxygenation issue but an intrathoracic pressure issue too.

An increase in thoracic pressure can be significant enough to collapse coronary arteries.

Easy to see where ventilating a nonperfusing heart could be a problem.

Chances are you will not ventilate too slowly, more likely too fast. In a hybernating state, tissues have a lower matabolic need. Introducing oxygen free radicals can break down cell membranes and permiating o2 into the cell can set of mitochondrial apoptotic cascades which are irreversible.

Less is often more when it comes to ventilation.

Consider BVM with CPR. If you bag at a rate of 12 per minute that reduces effective cardiac perfusion by 12 seconds. It takes approximately 5 compressions to build adequte perfusion pressure. At 100 compressions a minute that is a compression ~ 1.6 seconds. 1.6x5 = 8 so for every pause to vent, you will lose 8 seconds after the vent rebuilding perfusion pressure. If ventilating 2 times for 1 second in a (30/2 role) that is 12 seconds lost to vent. 1/2 that to 6 total pauses per minute 6x8=48 and it is possible to spend an entire minute performing CPR without sufficent perfusion pressure.

I agree, by capno is probably the best way. But all these numbers are not absolute in all people. (it would be much easier if they were)

Most of what you said up until "Consider BVM with CPR" is way over my head. I'm not educated to understand all that. I could just take your word for it, but with no basis for understanding it, and you not being my instructor, I really can't.

About the CPR, I understand the book method, but every time I've seen it done in the real world, it's one person continuously compressing and another continuously bagging. Except for pausing to check for return of spontaneous breathing and circulation, etc. None of the 30/2 that's the book method, it's both going on at the same time. And what you talk about in that paragraph not only makes it sound as if that's a good thing, it also makes it sound like even if one actually is doing the book 30/2 method, the less time you lose in the bagging part, the better—in other words, doing it at 12 bpm and getting it done quicker is better than spending more time doing it at 8 bpm.

In any event, I've made a list of points to discuss with the instructor tomorrow evening, and I want to thank everyone for all the things presented for my consideration.

 

[usalsfyre]

About the CPR, I understand the book method, but every time I've seen it done in the real world, it's one person continuously compressing and another continuously bagging. Except for pausing to check for return of spontaneous breathing and circulation, etc. None of the 30/2 that's the book method, it's both going on at the same time. And what you talk about in that paragraph not only makes it sound as if that's a good thing, it also makes it sound like even if one actually is doing the book 30/2 method, the less time you lose in the bagging part, the better—in other words, doing it at 12 bpm and getting it done quicker is better than spending more time doing it at 8 bpm.

Bagging should be continuous only if a secure airway is in place. Otherwise your very likely to end up with a fair amount of gastric distension, and resulting emisis. Not good....

You will feel like your bagging to slow. Your not, I promise. When I was regularly taking care of vent patients I set my initial rate at 10 assuming the pt wasn't hyperventilating before, and adjusted as needed based on ETCO2. Very rarely did it need to be changed. And the only patient I can recall that was hypoxic at this rate had massive pulmonary contusion interfering with gas exchange. Remember that positive pressure ventilation screws with hemodynamics (our bodies run on a negative pressure system) and artificial airways make it much harder to get rid of that pressure.

I would bet with the next AHA update (not the upcoming one in a few months) we quit ventilating patients in the first 10 minutes of CPR and focus on high quality chest compressions.

 

[Veneficus]

Most of what you said up until "Consider BVM with CPR" is way over my head. I'm not educated to understand all that. I could just take your word for it, but with no basis for understanding it, and you not being my instructor, I really can't.

Always glad to see the time I spend giving out knowledge for free that I have paid dearly for in time and money is not wasted.

 

[JJR512]

Always glad to see the time I spend giving out knowledge for free that I have paid dearly for in time and money is not wasted.

It's not that I don't appreciate your trying to help, it's just that if I don't understand something, it doesn't help me at all. I mean, I'm an EMT-B, and technically not even that since I didn't get recertified last year and am taking the class over again. I haven't had A&P, general biology, and all the paramedic classes. So I really don't know anything about "free radicals" and "mitochondrial apoptotic cascades". I don't know if it's my ignorance that needs to be excused, or your arrogance that you can just toss those terms around like everybody will know what you're talking about that needs to be excused. And I can't ask you to explain those to me, not unless you can give me a complete biology, anatomy, and physiology lesson to provide the framework I'd need to understand the explanation, otherwise I'd need to ask you to explain the explanation, then explain the explanation of the explanation, and so on. And that's not really fair for me to ask you to give me a couple of college-level courses for free.

So again, thanks for trying to help; I'm sorry it didn't work out for me, but I really am grateful that you did try. I guess I'll just have to take the bits that I actually could understand (from everyone), and discuss it all with my instructor tomorrow.

 

[Aidey]

Ok, I'm not trying to be a jerk here, but I tried to explain it to you without going into the science too much and you still dismissed what I had to say.

However, because I am a glutton for punishment, I will translate for you. This is your one freebie, if you don't understand something spend some time looking up the terms you don't understand so you can learn about it.

Don't foget it is not just an oxygenation issue but an intrathoracic pressure issue too.

It isn't just about how much oxygen you are giving the patient, it is also about how much pressure gets built up in the chest cavity.

An increase in thoracic pressure can be significant enough to collapse coronary arteries.

Too much pressure in the chest cavity can cause the vessels around the heart to collapse, and when they collapse blood can't flow.

Easy to see where ventilating a nonperfusing heart could be a problem.

You can ventilate all you want, but if those vessels are collapsed the heart isn't going to get any oxygen.

Chances are you will not ventilate too slowly, more likely too fast. In a hybernating state, tissues have a lower matabolic need. Introducing oxygen free radicals can break down cell membranes and permiating o2 into the cell can set of mitochondrial apoptotic cascades which are irreversible.

You will bag your patient too fast. When a person is in cardiac arrest they don't need as much energy to run their bodily functions because those bodily functions aren't functioning. If you give them more oxygen than they need you can set off a chain reaction of programed cell death, which there is no way to stop. Or, too much O2 = dead cells.

Less is often more when it comes to ventilation.

Don't ventilate too fast!

Consider BVM with CPR. If you bag at a rate of 12 per minute that reduces effective cardiac perfusion by 12 seconds. It takes approximately 5 compressions to build adequte perfusion pressure. At 100 compressions a minute that is a compression ~ 1.6 seconds. 1.6x5 = 8 so for every pause to vent, you will lose 8 seconds after the vent rebuilding perfusion pressure. If ventilating 2 times for 1 second in a (30/2 role) that is 12 seconds lost to vent. 1/2 that to 6 total pauses per minute 6x8=48 and it is possible to spend an entire minute performing CPR without sufficent perfusion pressure.

During CPR compressions create a blood pressure, and adequate blood pressure is needed to force the blood to go 'round and 'round and deliver oxygen. Every time you stop compressions to give a breath you cause the patients blood pressure to drop. Once it has dropped, you spend the first 5 compressions building it back up again. Between pausing to breathe and the 5 compressions it takes to build up a BP, it is possible that you may never reach an adequate BP to make that blood go 'round and 'round and deliver oxygen to the patient. Thus, less ventilation = a better blood pressure.

My own note: This is probably why we will be going to 50:2 or 100:2 (or even 50:1 or 100:1) CPR in the future. 30:2 is better than 15:2, but it is very possible with 30:2 we are still not building up an adequate blood pressure to deliver oxygen to the patient.

I agree, by capno is probably the best way. But all these numbers are not absolute in all people. (it would be much easier if they were)

Capnography (a paramedic skill) is awesome, but it doesn't work the same for all people.

Most of what you said up until "Consider BVM with CPR" is way over my head. I'm not educated to understand all that. I could just take your word for it, but with no basis for understanding it, and you not being my instructor, I really can't.

About the CPR, I understand the book method, but every time I've seen it done in the real world, it's one person continuously compressing and another continuously bagging. Except for pausing to check for return of spontaneous breathing and circulation, etc. None of the 30/2 that's the book method, it's both going on at the same time. And what you talk about in that paragraph not only makes it sound as if that's a good thing, it also makes it sound like even if one actually is doing the book 30/2 method, the less time you lose in the bagging part, the better—in other words, doing it at 12 bpm and getting it done quicker is better than spending more time doing it at 8 bpm.

In any event, I've made a list of points to discuss with the instructor tomorrow evening, and I want to thank everyone for all the things presented for my consideration.

There are two ways to do CPR, with an advanced airway and without. Without an advanced airway CPR is done with a 30:2 compression to breath ratio. When it is with an advanced airway compressions are constant. If you are seeing people do constant compressions without an advanced airway, they are doing it wrong.