Base deficit and dehydration

[Intheair]

can someone explain this relationship to me and how it pertains to our asleep patient in the or. Why does dehydration in the or cause a base deficit. Also, the other day I had a patient with s/p renal transplant...with a base deficit of -6 no matter how much fluid i gave him. I couldnt correct it. My attending said he probably had some RTA and told me to give bicarb. Was this the propper thing to do?

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[militarymd]

can someone explain this relationship to me and how it pertains to our asleep patient in the or. Why does dehydration in the or cause a base deficit. Also, the other day I had a patient with s/p renal transplant...with a base deficit of -6 no matter how much fluid i gave him. I couldnt correct it. My attending said he probably had some RTA and told me to give bicarb. Was this the propper thing to do?

Base deficit is a calculated number from an ABG....not helpful unless you also have a serum HCO3 available...

Continued and excessive administration of Normal Saline will induce a "base deficit" in an otherwise normal person.

As for RTA....treatment is base supplementation ...if you feel you need to treat a number.....in the short term, an abnormal "base deficit" from RTA is meaningless and harmless.

Acidosis is not a bad condition....what one should worry about is WHAT is causing the acidosis...

 

[toughlife]

can someone explain this relationship to me and how it pertains to our asleep patient in the or. Why does dehydration in the or cause a base deficit. Also, the other day I had a patient with s/p renal transplant...with a base deficit of -6 no matter how much fluid i gave him. I couldnt correct it. My attending said he probably had some RTA and told me to give bicarb. Was this the propper thing to do?

What fluids were you giving the patient? What was his chloride? If his chloride was elevated and you were giving NS you have to think of hyperchloremic metabolic acidosis. Seen it in the vascular ICU with post-op patients who got NS instead of LRs in the OR.

just a thought.

 

[Noyac]

Base deficit is a calculated number from an ABG....not helpful unless you also have a serum HCO3 available...

Continued and excessive administration of Normal Saline will induce a "base deficit" in an otherwise normal person.

As for RTA....treatment is base supplementation ...if you feel you need to treat a number.....in the short term, an abnormal "base deficit" from RTA is meaningless and harmless.

Acidosis is not a bad condition....what one should worry about is WHAT is causing the acidosis...

For the sake of discussion. Say you are giving LR or at least mixing it up enough and the HCO3 is normal. What's your approach. Mine is to give more fluids assuming healthy pt otherwise (healthy heart, lungs kidneys). I still rarely give Bicarb. Unless needed however in trauma I'm a bigger fan of THAM.

 

[militarymd]

If the serum HCO3 (bicarbonate) is normal...then there is no acidosis...so there is nothing to do.

 

[KGUNNER1]

If the serum HCO3 (bicarbonate) is normal...then there is no acidosis...so there is nothing to do.

Don't know where to start, the comment about adding NS and causing a hyperchloremic metabolic acidosis is correct. Common case is chasing a BE or BD (however it is reported in your hospital) with continued NS boluses without finding out why. The concern is that you are dealing with a hypoperfused state. A lactate can help determine this.

Other common causes are aggressive NS replacement in DKA, where you actually convert an anion gap metabolic acidosis to a non-anion gap metabolic acidosis.

The body does well with respiratory acidosis; it doesn't like metabolic acidosis, regardless of the etiology. Some are more severe (like lactate induced), but even hyperchloremic metabolic acidosis can increase morbidity.

Forgot what you learned about bicarb. It is an independent variable, I can make it go up and down just by controlling the pCO2 (try it on a vented patient sometime - nothing severe of course).

If you are interested, a very nice, clean, quantitative approach has been pioneered by Stewart and really brought into the clinical arena by European anesthesiologists. Check out this website, but there are others as well.
http://www.anaesthetist.com/icu/elec/ionz/Findex.htm#Stewart.htm

Click on the "ionz" icon on the left hand side.

This is something you all should really look into and understand.

Good luck,

kg

 

[militarymd]

Stuart theory is crap.....it is not helpful clinically at all...

and I completely disagree about metabolic acidosis not being well tolerated....

You're IM right....take a look at the clinic patients who walk around with RTAs that "tolerate" it with no problems....

I agree that, in the long term, weeks and months...chronic metabolic acidosis will cause progrressive metabolic derangments that are undesirable....but in the short term...hours to days...acidosis (not less than a pH of 7.2) is absolutely benigh.

 

[KGUNNER1]

Stuart theory is crap.....it is not helpful clinically at all...

and I completely disagree about metabolic acidosis not being well tolerated....

You're IM right....take a look at the clinic patients who walk around with RTAs that "tolerate" it with no problems....

I agree that, in the long term, weeks and months...chronic metabolic acidosis will cause progrressive metabolic derangments that are undesirable....but in the short term...hours to days...acidosis (not less than a pH of 7.2) is absolutely benigh.

Your ignorance and immaturity are very obvious here and don't warrant any more of my time.

Just put that effort towards opening your mind, shutting your trap, and trying to learn something a little different than what you already think you know.

kg

 

[militarymd]

Your ignorance and immaturity are very obvious here and don't warrant any more of my time.

Just put that effort towards opening your mind, shutting your trap, and trying to learn something a little different than what you already think you know.

kg

Ad hominem attacks is a sign of ..you know what....

In case you didn't know...the Stuart theory is not new....it had been around for years when I was in training over a decade ago....a concept that I discussed with multiple attendings as a resident and fellow a decade ago....and to residents as an attending since....

As I said...crap for the clinician....if you find it helpful in guiding you in the care of your patients....good for you...

Seems to me...you're the one stuck in what you have learned...and unable to move beyond... the "metabolic acidosis is bad"..."why?"..."because it's not 'normal'" stage.

 

[KGUNNER1]

Ad hominem attacks is a sign of ..you know what....

Sounds like you have a few gray hairs and dentures, so you should know better. Shame, shame.

The current critical care, anesthesiology, surgical literature is chock full of current papers on various etiologies of "acute" metabolic acidoses and how they are all detrimental on a cellular, immunologic, organ, and overall clinical level.

Granted, Stewart is cumbersome, I won't argue that, actually if you just calculate an anion gap corrected for albumin you'll get clinically close enough to the SIG that it is useful. If you calculate the SID, you'll identify hyperchloremia in less than 2 seconds, without it, many docs still just look at the absolute chloride level and if it is not "in the red" they think everything is okay.

In critically ill patients when lactate acidosis was suspected (i.e. ongoing resuscitation), metabolic acidosis in general was associated with about a 45% mortality when compared to those that don't have it. Lactate was associated with about a 56% mortality, SIG about 40% and chloride around 30% where no metabolic acidosis was associated with about 25% mortality.

Several papers highlight associations between the immune response, coagulation abnormalities, renal perfusion, post-operative N/V, etc... to hyperchloremia.

Please show me where I said Stewart's approach was new. I'd like to see that. I never stated it was new.

Not impressed with the example your setting.

kg

 

[militarymd]

As you said, "acidosis" is correlated/associated with increased morbidity/mortality/badness....as published in countless/countless articles.

However, academically, I always want to point out that when one interprets the findings of an article/study, one always need to remember what PATIENT POPULATION one the study is referring to.

In the setting of critical illness (trauma, sepsis, etc.), there is insufficient oxygen delivery and lack of efficient oxygen utilization which leads to the acidosis.....

Acidosis is a marker or canary bird for the underlying disease...so of course...acidosis is bad.....

A large portion of critical care medicine literature is dedicated to finding the holy grail monitor....one which guides the proper amount of fluid resuscitation without excessive sodium overload.

Looking at the acid/base balance is just one of many monitoring modalities looked at....filling pressures, gastric tono, lactate, delta down/up, RVEDI, SVO2, and countless others....

WHAT I AM SAYING is that simple acidosis in the patient popultation with RTA (congenital or drug/anesthesia induced) or saline administration...ie iatrogenic causes....is well tolerated..in the timeframe of hours to days....

I stand by the following:

Acidosis is not a bad condition....what one should worry about is WHAT is causing the acidosis...

oh and btw ..I thought you were done with me.

 

[Bougie]

I find that the base deficit is useful for guiding bicarbonate treatment. I typically only give bicarb if the pH is less than 7.25. The loading formula is body weight in Kg x base deficit x 0.3. I usually give half that amount in the first hour. I know there are a million other ways to do this...

 

[Noyac]

I find that the base deficit is useful for guiding bicarbonate treatment. I typically only give bicarb if the pH is less than 7.25. The loading formula is body weight in Kg x base deficit x 0.3. I usually give half that amount in the first hour. I know there are a million other ways to do this...

That is a cookie cutter approach. You pick a number and start a treatment. It may not be wrong but your a doctor and you are trained to address each pt and scenario individually. This is what differentiates you from a nurse. For example, if you have a pt who you are resuscitating after a trauma and you are at 7.20 pH then you may not need Bicarb but instead fluids or PRBC's. Just an example.

Look at Mil's statements and think about it for a minute. If you know the reason for the acidosis, hypovolemia for example, then fix the problem instead of treating the acidosis directly.

I will commend yo on your approach with the bicarb formula however. It is a calculated approach which does work well. I'm just cautioning you against knee jerk responses. Nice job, carry on.

 

[jetproppilot]

can someone explain this relationship to me and how it pertains to our asleep patient in the or. Why does dehydration in the or cause a base deficit. Also, the other day I had a patient with s/p renal transplant...with a base deficit of -6 no matter how much fluid i gave him. I couldnt correct it. My attending said he probably had some RTA and told me to give bicarb. Was this the propper thing to do?

Why am I bumping all these threads?

Because they are relevant.

And cool.

And more interesting than the political vibe currently dominating GasForums.

Time to tug the reigns back on the political s hit. And emphasize what most people come here for.

 

[jetproppilot]

Base deficit is a calculated number from an ABG....not helpful unless you also have a serum HCO3 available...

Continued and excessive administration of Normal Saline will induce a "base deficit" in an otherwise normal person.

As for RTA....treatment is base supplementation ...if you feel you need to treat a number.....in the short term, an abnormal "base deficit" from RTA is meaningless and harmless.

Acidosis is not a bad condition....what one should worry about is WHAT is causing the acidosis...

And, Geez.....

ANYBODY WANNA GO HEAD TO HEAD WITH MIL ON CLINICALLY RELEVANT INFO??

I dont.