Alkalosis/ Acidosis- Question?

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I'm not understanding how to differntiate between metabolic/respritory acidosis and alkalosis when given a patients vitals and lab values.

Example:

A diabetic client comes to the emergnecy room with a serum glucose of 650; ABG's: pH 7.10, CO2 30 mm Hg, HCO3 of 15 mEq/L. Based on these findings the nurse should anticipte immediate treatment for:

What's an easy way to distinguish the different alkalosis and acidosis??

Thanks,

-J

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This patient is in an acidotic state- note the pH of 7.10 (7.35-7.45 is normal- yes I know it says different things in different books, this is what my book says) and the HC03 (HCO3 is the appropriate value to look at for determining alk/aci states) is 15 mEq/L(20-29 normal). Wether or not it is respiratory or metabolic depend on the circumstances of the patients condition- have they been exposed to gases/enviromental hazards, are their breathing patterns abnormal or do they have a medical diagnoses at work? I would imagine that this patient would be treated with Sodium Bicarbonate or some sort of IV solution to try to raise their pH along with identification and elimnation of the source of their imbalanced pH. My advice on how to tell the difference is generally anything related to lungs/pulmonary is respiratory and everything else is metabolic. If anyone else has a better answer then please correct any mistakes I may have made I'm not an expert

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A way that works for me:

Look at the pH: a normal pH value is between 7.35-7.45. If the value is high, then write down an upward arrow and this represents alkalosis. If the value is low, then write a downward arrow and this represents acidosis.

Look at the PaCO2: normal value is between 35-45. If the value is high, write an upward arrow and this represents acidosis. If the value is low, write a downward arrow and this represents alkalosis.

Look at the HCO3: normal value is between 22-26. If the value is high, write an upward arrow and this represents alkalosis. If the value is low, write a downward arrow and this represents acidosis.

Use the pH value to determine whether the condition is acidosis or alkalosis. If all the arrows for the values point in the same direction, then the condition is metabolic. If the pH and PaCO2 arrows point in opposite directions, then the condition is respiratory.

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Specializes in Critical Care.

What's an easy way to distinguish the different alkalosis and acidosis??

Thanks,

-J

ROME: Respiratory Opposite, Metabolic Equal.

Respiratory Opposite means that if the pH and the CO2 are in opposite directions (one is low, one is high), the source is respiratory.

Metabolic Equal means that if the pH and HCO3 are in the same direction (both low or both high), the source is metabolic. Note: Often the CO2 will also be in the same direction here as a method of respiratory compensation.

Your patient is in partially compensated metabolic acidosis: their pH is less than 7.35, so they are in acidosis. Their HCO3 is low, and it is in the same direction as the pH, so this tells you it is metabolic. The CO2 is also low, which tells you they are breathing off CO2 in an attempt to raise the pH.

Basically, your body compensates oppositely. For instance, if you're in metabolic acidosis, respiratory alkalosis is the mechanism of compensation. This essentially means hyperventilation. You might need to encourage the patient to breathe faster on their own, or judging by the extreme acidosis they are in, you might be expecting to intubate the patient and mechanically hyperventilate them in order to blow off CO2 and raise their pH. Additionally, while alkalyzing agents such as HCO3 might be administered, the preferred treatment will be to identify and correct the cause. Is it diabetic ketoacidosis? Is a lactic acidosis from perhaps rhabdomyolysis? Metabolic acidosis can have some complex causes and may require complex treatments.

Edit: Didn't even see your glucose. Given that they are not getting glucose into their cells, their body has resorted to burning fat as a source of energy. The byproducts of the metabolism of fatty acids are ketones, which include acetone and several acids. A build up of these byproducts in the blood makes one acidotic. Your patient has diabetic ketoacidosis.

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Specializes in Critical Care.
A way that works for me:

Look at the PaCO2: normal value is between 35-45. If the value is high, write an upward arrow and this represents acidosis. If the value is low, write a downward arrow and this represents alkalosis.

Not good.

You can have low PaCO2 levels with compensated metabolic acidosis, and you can have high PaCO2 levels with compensated metabolic alkalosis.

Look at the HCO3: normal value is between 22-26. If the value is high, write an upward arrow and this represents alkalosis. If the value is low, write a downward arrow and this represents acidosis.

Ditto. If the HCO3 is elevated it can also be compensation for respiratory acidosis and if it's low it can be compensation for respiratory alkalosis.

The only determinate of acidosis versus alkalosis is the pH.

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Specializes in Maternal - Child Health.

What's an easy way to distinguish the different alkalosis and acidosis?

-J

For the purposes of interpreting blood gasses, it is easiest to stick with hard and fast values, not ranges.

For pH, use the norm of 7.40. Anything lower is acidotic. Anything higher is alkalotic. In your example, your patient is clearly acidotic.

Next look at the pCO2. Again use the hard and fast value of 40. Anything higher is abnormally elevated, likely due to respiratory depression. Anything lower indicates that CO2 is being blown off at an increased rate, probably due to tachypnea, which is a compensation for metabolic disturbances. Your patient's pCO2 is decreased, indicating that she is probably tachypneic in an effort to blow off CO2 and compensate for the excess of metabolic acids in her bloodstream.

Lastly look at the HCO3. Normal range is 22-26. Use 24 as your hard and fast value. HCO3 of less than 24 indicates a base deficit. Greater than 24 is a base excess. Your example shows a significant base deficit.

Your patient has a metabolic acidosis with respiratory compensation. Given the elevated blood sugar level, what do you think caused the metabolic acidosis? What treatment would you anticipate?

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Specializes in med/surg, telemetry, IV therapy, mgmt.

this is addressed in several places on sticky threads:

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Specializes in ED, ICU, MS/MT, PCU, CM, House Sup, Frontline mgr.

OP: Use Daytonite's links. I did this for my exam a few weeks ago and was able to find a strategy that worked without failure. No matter what question I got I answered correctly even given the little information you posted. GL! In fact, the information you posted is enough to know that it is Uncompensated Metabolic Acidosis.

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hi!

all the information posted here is great. i wanted to add my 2 :twocents: and attach this file that was on one of my old instructor's website. hope its also helpful to you. :up:

jadu1106 :heartbeat

Arterial Blood Gases Basic Principles.doc

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i'm not understanding how to differntiate between metabolic/respritory acidosis and alkalosis when given a patients vitals and lab values.

example:

a diabetic client comes to the emergnecy room with a serum glucose of 650; abg's: ph 7.10, co2 30 mm hg, hco3 of 15 meq/l. based on these findings the nurse should anticipte immediate treatment for:

what's an easy way to distinguish the different alkalosis and acidosis??

thanks,

-j

this is the best link i have ever foun in explaining acid base.

realnurseed (education for real nurses by a real nurse)

if it doesn't bring you right to the page look on the tool bar on the left hand column and scroll down to ez way to remember abg

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