Sodium Bicarb

[tchristifulli]

So you get ROSC and you see a huge influx of C02. How long do you wait to give bicarb if the co2 remains elevated? Or is bicarb over rated and can cause more etc02?

 

[Jambi]

This is a great question...and a couple things that come to mind that I do not know.

1. How acidotic are typical arrest patients?
2. How quickly do pH levels return to normal after ROSC?

a. shouldn't a properly "compressed" and ventilated Pt maintain a somewhat regular pH (within reason) during resus?

Protocol for us is to get a 12-lead after ROSC, so for my money I think I'd wait to see how well the patient is oxygenating, and or what the 12-lead shows.

Please feel free to expose the flaws/gaps in my thinking. I am a new paramedic after all, but feel like I should know this.

 

[Jambi]

Did some quick searches and found some interesting articles. Both of them deal with the usefulness of ETC02 in identifying ROSC. We know that already of course.

This first one suggests that ABG values are less useful than venous samples during resus.
http://www.nejm.org/doi/pdf/10.1056/NEJM198607173150303

This second one is more interesting because they measured values during and after resus in those patients with ROSC, including peak values, but it's the following paragraph that interests my though process the most. This article also suggests that external bicarb may increase levels ETC02 levels, but the impact is likely minimal when compared to what is seen with ROSC.

The end-tidal C02 value peaked in all cases within two to five minutes of ROSC at a level that was almost three times greater than the value before ROSC. Within the next several minutes, the end-tidal C02 concentration slowly declined to a stable value in all patients that maintained ROSC.

article

So from what the latter is suggesting. it would seem that rapid buffering begins to occur after the introduction o2, and likely peaks at between 3-5 minutes, but doesn't return to values for some time. It still doesn't answer how fast it happens, or whether external bicarbonate would be beneficial. I would think it could be so long as ventilation and cardiac function is adequate to support gas clearing.

My next is how to make the clinical decision to use it? My worry is over buffering and causing an alkalotic state...which I think it the original question...lol

 

[chaz90]

I don't think I'd give bicarb in this scenario. No proven benefit for it during resuscitation, and even less post ROSC. If the patient has been resuscitated, we're moving in a positive direction and I don't need to throw another potentially harmful medication into the mix. Acid base balance is a complex and delicate science when applied to the body, and most ED docs don't even like to mess around with it too much. This is a job best left for ICU management, especially seeing as I don't have ABG values in the field and am just firing blindly at assumed acidosis. On a semi related note, my paramedic instructor used to refer to Sodium Bicarbonate as "pharmacological last rites" when applied to patients in arrest. Just something I found somewhat amusing...

 

[Jambi]

Here's more

this article is old but has useful information.

Finally, current studies indicate that the rationale of alkalinization during cardiac arrest must be critically examined in terms of ultimate benefit. Bicarbonate induced alkalosis, hypernatremia, hyperosmolality, and mixed venous hypercapnia are more likely to compromise rather than improve ultimate survival.’011 Objective evidence fails to securely establish that beneficial effects of alkali, especially sodium bicarbonate, outweigh these risks.

But then there's this article that supports it...

Conclusions:  Earlier and more frequent use of SB was associated with higher early resuscitability rates and with better long-term outcome. Sodium bicarbonate may be beneficial during CPR, and it should be subjected to a randomized clinical trial.

The first quote and article does a good job of summarizing my concerns.

 

[Anonymous]

I don't think I'd give bicarb in this scenario. No proven benefit for it during resuscitation, and even less post ROSC. If the patient has been resuscitated, we're moving in a positive direction and I don't need to throw another potentially harmful medication into the mix. Acid base balance is a complex and delicate science when applied to the body, and most ED docs don't even like to mess around with it too much. This is a job best left for ICU management, especially seeing as I don't have ABG values in the field and am just firing blindly at assumed acidosis. On a semi related note, my paramedic instructor used to refer to Sodium Bicarbonate as "pharmacological last rites" when applied to patients in arrest. Just something I found somewhat amusing...

I would agree with this.

Ensuring adequate ventilation and perfusion should be the focus.

also resist the urge to hyperventilate based on the capnography readings.

 

[Anonymous]

You are gonna drive yourself nuts researching this. One of those debatable topics with good arguments on both sides.

This JEMS article does a good job summarizing things: http://www.jems.com/article/patient-care/sodium-bicarbonate

 

[MSDeltaFlt]

So you get ROSC and you see a huge influx of C02. How long do you wait to give bicarb if the co2 remains elevated? Or is bicarb over rated and can cause more etc02?

I would not give NaHCO3 post ROSC without ABG's giving a diagnosed metabolic acidosis requiring alkalinization. If your PaCO2 and/or EtCO2 is elevated then you have a respiratory problem. Giving NaHCO3 will increase PaCO2 thereby decreasing pH making everything worse. Drop the PaCO2 first. If the pH is still low due to low HCO3, then by all means give bicarb. If the pH is low despite hyperventilation, nkrmal HCO3, and patient is euthermic, then check CMP. Odds are patient has an Anion Gap acidosis. Might need K+, Na+, and/or Cl-.

 

[teedubbyaw]

I would not give NaHCO3 post ROSC without ABG's giving a diagnosed metabolic acidosis requiring alkalinization. If your PaCO2 and/or EtCO2 is elevated then you have a respiratory problem. Giving NaHCO3 will increase PaCO2 thereby decreasing pH making everything worse. Drop the PaCO2 first. If the pH is still low due to low HCO3, then by all means give bicarb. If the pH is low despite hyperventilation, nkrmal HCO3, and patient is euthermic, then check CMP. Odds are patient has an Anion Gap acidosis. Might need K+, Na+, and/or Cl-.

Nice post. I was about to say this seems more like respiratory and bicarb is not indicated for respiratory acidosis.

 

[Aprz]

CO2 + H2O <-> H2CO3 <-> HCO3- + H+

When sodium bicarbonate (NaHCO3) is administered, the bicarbonate (HCO3-) is suppose to mix with the hydrogen ions (H+) to make carbonic acid (H2CO3), and the carbonic acid dissolves into water (H2O) and carbon dioxide (CO2). The patient can breath out or we can ventilate the carbon dioxide if aveoli perfusion is good which is how we increase the pH, or reduce acidosis. If the patient is already breathing out a lot of carbon dioxide, there is no point in administering it cause they already are breathing out the carbon dioxide. If you administer sodium bicarbonate, it would increase their end tidal CO2 (EtCO2).

 

[Dwindlin]

Only one good reason to ever "push" an amp of bicarb. I'll occasionally toss a few amps in a liter and run it in with my maintenance fluids.

 

[Carlos Danger]

Only one good reason to ever "push" an amp of bicarb. I'll occasionally toss a few amps in a liter and run it in with my maintenance fluids.

Tricyclic OD

FTW

 

[NomadicMedic]

Crush/hyperK.

 

[Dwindlin]

Tricyclic OD

FTW

Crush/hyperK.

Imminent herniation. Amp of Sodium Bicarb is crazy hypertonic. I'll never understand it, but I can keep all the Sodium bicarb I want on random unlocked carts and no one bats an eye when someone asks for it to be pushed. But I mention 3% saline and 50 people have an anger stroke unless I plan on placing a central line.

 

[DrankTheKoolaid]

Haha Weingart says the same exact thing about bicarbonate and 3%

 

[Dwindlin]

Haha Weingart says the same exact thing about bicarbonate and 3%

That's because he's a smart guy. That blog was one of my favorite resources during school.

 

[fma08]

Haha Weingart says the same exact thing about bicarbonate and 3%

Thanks for pointing out Weingart. I hadn't seen his blog before, but it looks great for school.

 

[Dwindlin]

Thanks for pointing out Weingart. I hadn't seen his blog before, but it looks great for school.

His vent and acid base lectures are probably the best I've ever heard.

 

[fma08]

His vent and acid base lectures are probably the best I've ever heard.

I'll keep that in mind. Thanks!

 

[18G]

I would not push sodium bicarb in the field for a ROSC. At that point I would focus my actions on optimizing the patient's perfusion and ventilation which will start to correct the acidosis.

As others said, I've seen no support for bicarb with ROSC. Maintain blood pressure and good ventilation and induce hypothermia.