bagging rate for a desaturated patient

[ketap]

hi, this might be a silly question, i had a patient who just has been intubated, the patient's SpO2 was 57-62%..so to increase the O2 Saturation , should i then hyperventilate the patient(bagging rate :as fast as possible) or should i keep it at a constant steady rate maybe at 12 - 20 times per minute?

this intrigued me , because sometimes hyperventilating will cause great improvement at Sao2 but sometimes maintaining steady state rate will result the same thing---and i think this is what the books tell us to do (e.q maintaining 10 times per minute in cardiac arrest patient --ACLS gudieline or 12 times per minute for respiratory arrest)

but i found also that overtime, hyperventilating will also result in decreasing FiO2 and in the end it will decrease O2 saturation also...

so ,what should i do? people keep telling me to just hyperventilate the patient but i am not sure if it is the right thing to do..please give your opinion about this..thx u very much,friends 🙂

oh,one thing: Can a rocuronium cause cardiac arrest to a 11 month old child with pneumonia and sepsis? thx u again

regards,Ketap🙂

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[WilcoWorld]

Hypoventilated patients need to be ventilated, not hyperventilated. Bagging as fast as you can is almost never going to benefit the patient.

 

[WilcoWorld]

oh,one thing: Can a rocuronium cause cardiac arrest to a 11 month old child with pneumonia and sepsis? thx u again

Yes, it can. But so can pneumonia and sepsis.

 

[ketap]

so, what bagging rate would you suggest? between 12 to 20 times per minute with an adequate volume just to bring the chest rises?thx u 🙂

 

[southerndoc]

Hypoventilated patients need to be ventilated, not hyperventilated. Bagging as fast as you can is almost never going to benefit the patient.

I disagree. Hypercapnea is a cause of hypoxemia, and as such, hyperventilation will help oxygen saturation (particularly in the short term). Remember the alveolar gas equation.

Hyperventilation can only cause hypoxemia with breath stacking.

 

[TheBlueBlazer]

I'm not sure that hypercapnea can cause hypoxia per se. Hyperventilation beyond 6 or 7 breaths is pointless (maybe a couple more if your sat is super low) provided you are ventilating with 100% FiO2, because once you've filled the alveoli and your dead space with 100% Oxygen, you're able to supply any alveolar blood O2 demands while still maintaining a high partial pressure of oxygen within the alveoli. If you're bagging with 100% O2 and you're not getting your sats up within a few normal tidal volume breaths you need to either add a peep valve to your bag, you didn't fill your reservoir, or the patient has some sort of lung disease like ARDS or unventilated segment like one filled with fluid or mucus plugged that is preventing the sats from coming up. Also, don't forget that pulse ox tends to lag a little bit.

 

[Colbert]

If you have a patient who's oxygenation is low, the ways to increase that is more oxygen (FiO2) and to increase PEEP. PEEP will hopefully pop open any of those collapsed alveoli. You can throw a PEEP valve on your BVM.

It's important to recognize that oxygenation and ventilation are basically two different processes. You can have 100% O2 sat but a PCO2 of 100 as well and be screwed.

 

[southerndoc]

Ventilation and oxygenation are two different things, but they are related. This is why severely hypercapneic patients are very often hypoxemic. Hyperventilation should be trialed before adding PEEP. If the patient is still hypoxemic after hyperventilation, then add PEEP (provided you are already ventilating with an FiO2 of 1).

 

[Hernandez]

Ventilation and oxygenation are two different things, but they are related. This is why severely hypercapneic patients are very often hypoxemic. Hyperventilation should be trialed before adding PEEP. If the patient is still hypoxemic after hyperventilation, then add PEEP (provided you are already ventilating with an FiO2 of 1).

Just a slight tweak..... Sometimes hyperventilation can induce PEEP and improve oxygenation by increasing mean airway pressures. So when I see a pt who responds to brisk bagging then drops othe vent, the majority of the time it will be a sign to me that they need more peep. I have a low threshold for throwing a peep valve on an ambu bag, but that doesn't mean I crank it up past the base setting.

The answer to the original question is.....it depends on the scenario.......

 

[ketap]

hi ,Friends, i am so excited to have so many opinion..thx u very much 🙂 but i have few more questions :

Southerndoc: this is what makes me confuse..lots of people surrounds me tell me that hypoventilation makes hypercarbia and then makes hypoxia..i agree to that...but, why do we need another hyperventilation if we have done adequate preoxygenation (almost always done hyperventilated,i believe) before?

Henrnandez: that is interesting..thx u, i think that explain why sometime we can have increased Sa O2 with hyperventilation..never thought about that before...but, i have question :what "base setting" you refer to?

Colbert: how can i create PEEP with my BMV bag? i am sorry, i really have never apply PEEP with BMV bag before..🙂

regards, Ketap 🙂

 

[Hernandez]

The peep valve we use if you place on the bag provides 5cm peep unless you crank the valve down.

 

[jwk]

If you have a patient who's oxygenation is low, the ways to increase that is more oxygen (FiO2) and to increase PEEP. PEEP will hopefully pop open any of those collapsed alveoli. You can throw a PEEP valve on your BVM.

It's important to recognize that oxygenation and ventilation are basically two different processes. You can have 100% O2 sat but a PCO2 of 100 as well and be screwed.

This!!!

Slower deeper breaths and a little PEEP or positive pressure in whatever way you can manage. Also - remember most SaO2 monitors have a 12-second delay/processing time AND if you don't have a pleth waveform (artifact, movement, etc), whatever number you see is meaningless.

 

[patch28]

If you have a patient who's oxygenation is low, the ways to increase that is more oxygen (FiO2) and to increase PEEP. PEEP will hopefully pop open any of those collapsed alveoli. You can throw a PEEP valve on your BVM.

It's important to recognize that oxygenation and ventilation are basically two different processes. You can have 100% O2 sat but a PCO2 of 100 as well and be screwed.

And, conversely, if the hospital O2 is accidentally hooked up to 100% nitrogen, you could bag like a madman and get the pCO2 down to 30, but because you'd be delivering a hyooxic gas mixture, your sats would be in the gutter as well.

 

[Hamhock]

Another addition to the discussion:

Stop worrying about how to bag or when to add the PEEP valve to the traditional BVM in a patient who was just intubated.

Don't use the BVM at all.

Just put the patient on the vent. Adjust your PEEP and Fi02.

It drives me nuts when I see RT or residents trying to bag most patients after intubation. Do they really think they are better than the machine to their left?

HH

 

[Hernandez]

Another addition to the discussion:

Stop worrying about how to bag or when to add the PEEP valve to the traditional BVM in a patient who was just intubated.

Don't use the BVM at all.

Just put the patient on the vent. Adjust your PEEP and Fi02.

It drives me nuts when I see RT or residents trying to bag most patients after intubation. Do they really think they are better than the machine to their left?

HH

<10% of time a human is better than the machine.

 

[UnderwaterDoc]

I don't see the harm behind some hyperventilation if sats are dropping. I understand the physiology and the fact that it will likely not make much of a difference to bag faster, but I dare anyone to sit there, watch the sats plummet, and keep bagging at 8/minute.

 

[WilcoWorld]

the patient's SpO2 was 57-62%..so to increase the O2 Saturation , should i then hyperventilate the patient(bagging rate :as fast as possible) or should i keep it at a constant steady rate maybe at 12 - 20 times per minute?

I'd like to clarify something here. The OP referred to hyperventilation as "bagging rate :as fast as possible". That is pretty much NEVER going to be a good idea. Yes, if a patient is hypercapnic then he may need his rate increased, but not all hypoxia is associated with hypercarbia.

Most of the time, when a patient is hypoxic, the modifications that his bagging needs are 1) Better seal 2) Clearing of obstruction (like a big tongue) and 3) Adequate exhalation.

Steady bagging with good technique at a reasonable rate is MUCH better than hyperventilation in almost every case (salicylate toxicity being an exception).

 

[Hernandez]

I don't think I've ever seen anyone (doc, nurse, RT) bag at an appropriate rate,

 

[Arcan57]

I'd like to clarify something here. The OP referred to hyperventilation as "bagging rate :as fast as possible". That is pretty much NEVER going to be a good idea. Yes, if a patient is hypercapnic then he may need his rate increased, but not all hypoxia is associated with hypercarbia.

Most of the time, when a patient is hypoxic, the modifications that his bagging needs are 1) Better seal 2) Clearing of obstruction (like a big tongue) and 3) Adequate exhalation.

Steady bagging with good technique at a reasonable rate is MUCH better than hyperventilation in almost every case (salicylate toxicity being an exception).

If you're trying to increase intrathoracic pressure to decrease venous return to prevent ROSC in someone with an extended down time then hyperventilation may be just the thing.

 

[Siggy]

Did you check to make sure you were getting a good reading on the pulse oximeter (good waveform if waveform pleth is available, good bar bounce if it's just the bars? Is the number changing slightly (+/- 1-2 or so)?)? More than once I've seen people make decisions off of a pulse ox reading that wasn't accurate if they took the time to look at more than just the displayed number.

 

[The White Coat Investor]

If a patient desats due to prolonged intubation or something I bag fast until the SpO2 is rising rapidly, then bag at what I would consider a more typical rate. Perhaps 5 or 10 fast breaths. Certainly not long term.

 

[jwk]

If a patient desats due to prolonged intubation or something I bag fast until the SpO2 is rising rapidly, then bag at what I would consider a more typical rate. Perhaps 5 or 10 fast breaths. Certainly not long term.

SaO2 is not a function of respiratory rate - it's a function of tidal volume/inspiratory pressure. If you're bagging quickly, you're likely not generating enough of either one.

 

[Birdstrike]

There's no exact answer for this. You don't want them desatting, but you don't want hyperventilation either. Plus, who's counting? Get them on a vent.

 

[RustedFox]

Another addition to the discussion:

Stop worrying about how to bag or when to add the PEEP valve to the traditional BVM in a patient who was just intubated.

Don't use the BVM at all.

Just put the patient on the vent. Adjust your PEEP and Fi02.

It drives me nuts when I see RT or residents trying to bag most patients after intubation. Do they really think they are better than the machine to their left?

HH

There's a really good talk on EmCrit.org about "using the vent as a BVM". Totally worth the listen.

 

[The White Coat Investor]

SaO2 is not a function of respiratory rate - it's a function of tidal volume/inspiratory pressure. If you're bagging quickly, you're likely not generating enough of either one.

I give them BIG fast breaths. Happy?

If they desatted to say 75%, then I continue this until I see the number start rising quickly. We're talking less than 30 seconds here.

Probably doesn't matter either way. I certainly can't prove my way is better.

 

[WilcoWorld]

👍

If you're trying to increase intrathoracic pressure to decrease venous return to prevent ROSC in someone with an extended down time then hyperventilation may be just the thing.

👍

 

[The White Coat Investor]

👍

👍

If we're talking about dead people, then yes, ventilation doesn't seem to help. In fact, if they're still dead when they get to us, I've found very little that helps. Don't get me wrong, I get ROSC as often as you do......but the truth is if the medics don't get it, then it doesn't matter much if you do.

 

[RPedigo]

If someone had a difficult airway and was hypoxemic from the apneic time (and had an adequate preoxygenation), they are almost certainly also hypercapneic. Although as stated before that ventilation and oxygenation are different processes, they are also to some extent related. From the alveolar air equation you can see that they are related:

PAO2 = FiO2 (Pbarometric - Pwater) - (PaCO2/R)

So plugging in normal values for a healthy patient breathing room air:
PAO2 = 0.21 (760 - 47) - (40/0.8) = 100 mmHg

If they were adequately oxygenating but only had half the minute ventilation, their CO2 would be 80 (PACO2 is inversely proportional to minute ventilation) -- if you just plug those numbers back in to the alveolar air equation:
PAO2 = 0.21 (760 - 47) - (80/0.8) = 50 mmHg

So from the alveolar air equation, at least, it seems that just simply having hypercapneia can worsen hypoxemia. Granted a CO2 change acutely to 80 from 40 would have its own problems, so this is an extreme example. Since the pH changes 0.08 for every 10 mmHg CO2, you'd also have your pH dropped to 7.08. But based on this,hypercapneia in and of itself can also contribute to some extent to hypoxemia and the processes are not completely independent.

Given that, it would seem reasonable to me to bag someone initially more rapidly and deeper to clear their carbon dioxide load as long as there was appropriate expiratory time and not excessive tidal volumes to prevent breath stacking and barotrauma. I'd be interested to hear the thoughts of others regarding this, though.

 

[southerndoc]

Hyperventilation with a normal pCO2 will also increase oxygenation in the same manner. Hence the reason I referred to the alveolar gas equation earlier. Plugging in a pCO2 of 40 and then changing that to 15 by hyperventilation will also raise your O2 saturations. However, this is a temporary fix.