Levo and pH
- 1Oct 16, '10 by Maevishwe had the most awful night last night starting at the beginning of the shift (1945). got a "code blue to c-section #2" page overhead so the sc and myself (the float/resource nurse) ran there and they're doing compressions on a lady who's not even closed up from her c-s yet! baby was good, but the mom ended up coming to us and it was basically an all night medical code with another official "code blue" called on her at around 0200. first time i've cried on the way home from work
anyways, my question was about the levo not working for her bp. her ph was in the 7.2 range on the first abg and she got an amp of hco3. then on the next abg (maybe an hour later) it was down to 7.19. then, since the bp was dropping so fast, the pma in the unit said to just run it wide open, but it wasn't working. the primary nurse (who's very experienced, whereas i've barely been in the icu for 2 years) said that the levo wouldn't do anything for the bp while the ph was so low. can someone explain this?
god, every night i work i seem to be overwhelmed with everything i don't know!!!
- 0Oct 16, '10 by ChiscaThink like a cell. If your body reverts to anaerobic respiration you are producing alot of lactic acid. This causes vasodilation and the levophed cannot overcome this even with boluses of sodium bicarb. As a neurotransmitter levophed facilitates communication between nerve cells and the muscles. If the muscles that constrict the blood vessels don't receive the message they won't constrict. Without correction of the underlying cause of acidosis it is only a matter of time before death arrives.
- 0Oct 16, '10 by General E. Speaking, RN(((hugs))) sorry you had a rough shift. I had the same problem. I have been nursing for a while but moved to ICU recently so I am still learning. My pt was on Neo, Levo, Epi AND Vasopressin. SBP barely 70s. ABGs read that pH was 6.9. After the bicarb the BP came up a bit and the charge nurse said "thanks to the bicarb". I, too, questioned why. Pretty much explained what the other poster said above. He went on to explain that acidosis also decreases the body's response to catecholamines.
- 0Oct 17, '10 by CRIMSONPH and volume both sound as though they may have been a contributing factor. If there is no volume, you can squeeze the Levo all you want but it will not help if there is nothing there. (Csection loss of fluids and blood)
A bicarb drip may have been a better option than just bolus'.
- 0Oct 19, '10 by MaevishThanks for the explanations! One thing though, I went to an amazing, all-day cardiac class and learned a ton. The only thing is, no one ever mentions the necessity of having a near-normal pH so that the levo (or whatever) does its job. Is this something that everyone assumes we know?
Also, in our septic pts who are adequately hydrated and the HP is still low, we start levo and the BP goes up. And these pts have really jacked up pG levels too, so I'm confused.
I just wanna understand it!
- 0Oct 21, '10 by RN1980having a decent ph level in order for drugs to work is not only a concern for levophed but for pretty much the rest of the presser family of drugs. like the above poster explained, if the cells are splitting open from a terrible ph there are no cells or only partailly functional poor cells to work with.
- 1Feb 7, '11 by OneHeartMenderlactic acidosis is a physiological condition characterized by low ph in body tissues and blood ([color=#0645ad]acidosis) accompanied by the buildup of [color=#0645ad]lactate especially [color=#0645ad]d-lactate, and is considered a distinct form of [color=#0645ad]metabolic acidosis.[color=#0645ad] the condition typically occurs when cells receive too little oxygen ([color=#0645ad]hypoxia), for example during vigorous exercise. in this situation, impaired cellular respiration leads to lower ph levels. simultaneously, cells are forced to metabolize [color=#0645ad]glucose [color=#0645ad]anaerobically, which leads to lactate formation. therefore, elevated lactate is indicative of tissue [color=#0645ad]hypoxia, [color=#0645ad]hypoperfusion, and possible damage. lactic acidosis is characterized by lactate levels >5 mmol/l and serum ph <7.3.
norepinephrine constriction of small terminal arterioles,on a2-mediated constriction. http://circres.ahajournals.org/cgi/reprint/66/6/1643
which is largely dependent on a2-receptors, was markedly
reduced by acidosis. the data suggest that
increases in local co2/h' concentration produced by
altered parenchymal tissue metabolic rate, oxygen
delivery, or blood ph may directly influence adrenergic
responsiveness of microvessels by a selective action
- 0Feb 7, '11 by TakeBackVasoconstriction of the smooth muscle cells on your vessels requires appropriate enzyme function. As your bloodstream is flooded with H+ (in your pt's metabolic acidosis), the enzymes deform and the "lock and key" mechanism fails. You can give all the norepi you want, but it won't work very well.
7.20 is severe acidosis. One amp HCO3 is a joke to that pH. As was already posted, this pt should get 2-4 amps IVP stat and a bicarb gtt. You can calculate the bicarb needed based on the pt's weight and base deficit, but in a code situation just push it in and fine tune it later.
The same principle for vascular smooth muscle also applies to cardiac contractility, so she had tone and pump failure most likely.
- 3Mar 23, '11 by tahoe77Absolutely, GREAT question!
As your body becomes more acidic or aklaline the proteins in your body and
the structure of different drugs, enzymes, metabolites denature and break
down. When your pH falls out of normal range in either direction the
structural shape of the molecules in your body are compromised.
Drugs that work before no longer work and are useless.
Once a molecule has an altered shape it no longer
fits in the receptor site for which it correlates.
If this is happening in your pt and you have
very low pH consistantly consider a bicarb gtt. Turn up
the rate on the vent, increase the tidal volume and try to figure out why they
are so damn acidotic. Are the kidney failing?
Sepsis? Flush out the lactate.
think of putting milk in lemon juice. It curdles right?
Thats because the acidic environment denatures
the protein in the milk.
The acidic environment is doing just that to your
body and all the other substances inside it.
Clear as mud?