Hello all, I need help in understanding this one ABG problem.
For most scenarios, I understand why something is a respiratory or metabolic cause. For the questions that that have both the CO2 and HCO3 going in the same direction, I am still confused.
For example: pH is 7.33, PaCO2 is 34, HCO3 is 27, and PO2 is 96. The answer is Metabolic acidosis; partially compensated.
Why is it a metabolic cause rather than a respiratory cause? Both values of CO2 and HCO3 are technically moving towards "alkaline," so I cannot tell what is causing the acidosis. Also, is it partially compensating b/c the CO2 and bicarb are going in the same direction?
Respiratory opposite metabolic equal is ROME. You can use it to determine the primary cause by looking at the pH and the PaCO2. If they are moving in opposite directions (pH up PaCO2 down or vise-versa) it is respiratory in the same direction (or equal) it is metabolic.[/quote']
After trying to logically learn this concept, I came across ROME a few years ago and have never looked back.
Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
Resp = lungs / Met = kidneys
Acidosis = low pH / Alkalosis = high pH
Respiratory acidosis: Hypoventilation, increased CO2 levels. The lungs cannot remove enough CO2 that the body produces (example - airway problems, COPD)
Respiratory alkalosis: Hyperventilation, low CO2 levels. Your body is breathing in more O2, and there is not enough CO2 to maintain balance (example -
Metabolic acidosis: Increase in acid production, kidneys are not removing acid from the body efficiently (example, renal failure)
Metabolic alkalosis: Increase in bicarbonate (for example, think too many antacids, or loss of GI secretions through suction)
Hello all, I need help in understanding this one ABG problem.
For most scenarios, I understand why something is a respiratory or metabolic cause. For the questions that that have both the CO2 and HCO3 going in the same direction, I am still confused.
For example: pH is 7.33, PaCO2 is 34, HCO3 is 27, and PO2 is 96. The answer is Metabolic acidosis; partially compensated.
Why is it a metabolic cause rather than a respiratory cause? Both values of CO2 and HCO3 are technically moving towards "alkaline," so I cannot tell what is causing the acidosis. Also, is it partially compensating b/c the CO2 and bicarb are going in the same direction?
Any help would be greatly appreciated.
There is a typo somewhere in this question. With an elevated bicarb, metabolic can't be a primary derangement, with a low CO2, respiratory can't be primary.
Other big causes of metabolic acidosis are aspirin OD (that's salicylic ACID) and hypoxic tissue (like mesenteric artery thrombosis, resulting in a whole lot of anaerobic metabolism in the gut). But either of those, or any other metabolic acidoses for that matter, pretty immediately consume bicarb, so you would never see an elevated bicarb in metabolic acidosis.
In a metabolic acidosis, you would see low bicarb, and the compensatory mechanism would be hyperventilation to decrease CO2 below normal. You do not have that combination in this question.
In a respiratory acidosis, you would have a high CO2, and the (chronic) compensation would be elevated bicarb. You don't have that combination in this question either.
Your thinking is completely correct-- the question / answer is wrong.
Heres how i learned and understood it dont overthink it ok just learn this trick and the levels ph 7.35-7.45 bicarb or hco3 22-28 co2 35-45 po2 80-100 if ph is below 7.35 its acidic if above 7.45 its alkaline if ph and co2 or po2 are oPPositeor diffeRRENT= ResPiratory . Rember that different has an R = Resp. If the ph and co2 or po2 are saMe or both decreased or elevated= Metabolic saMe has an M = Metabolic. Trick always work. If hc03 is elevated or decreased and p02 and c02 are normal its meatabolic. Hope this helps and doesnt confuse you!
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