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Normal Values
Etiology and Clinical Manifestations
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Quick Reference

    Metabolic Acidosis
    Clinical Manifestations
    • hyperkalemia: shift of acid to ICF and K+ to the ECF
    • anorexia, nausea, and vomiting
    • warm, flushed skin
    • cardiac dysrhythmias & CNS dysfunction
    • headache, diarrhea, tremors

    Metabolic Alkalosis
    Clinical Manifestations
    • cardia dysrhythmias; seizures; confusion; muscle twitching, agitation
    • >pH;>HC03; normal PaCo2 or elevated if compensation occurs

    Respiratory Acidosis
    Clinical Manifestations
    • > PaCo2; HCO3 is normal or > with renal compensation
    • vasodilatation; cardiac dysrhythmias, tachycardia, somnolence, decreased ventilation

    Respiratory Alkalosis
    Clinical Manifestations
    • > pH; < PaC02; HCO3 normal or low due to compensation
    • nausea, vomiting, tingling of fingers
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Assessment :: Assessment Step 2 :: Respiratory vs. Metabolic

    Step Two: Once you have determined the pH, you can move on to determine the 'primary' problem, or which system, respiratory or metabolic is the prime messenger. Let's look at the two systems and understand the rationale behind determination of the 'primary' problem.

    Respiratory System

    If you keep in mind that carbon dioxide acts as the ‘acid’ of the human body, you will be able to determine if the primary acid-base imbalance is respiratory. Chemically speaking, there is an equilibrium between carbonic acid and bicarbonate. Therefore, just remember that an increased PaCO2 (greater than 45mmHg) along with an acidosis (pH less than 7.35) represents a RESPIRATORY ACIDOSIS. If you have a situation where there is a decreased PaCO2 (less than 35mmHg) and an alkalosis (pH greater than 7.45) you will have a RESPIRATORY ALKALOSIS! Easy. Right?

    Metabolic System

    Keep in mind that HCO3 represents a ‘base’ situation, and if there is an increased HCO3 (greater than 26 mEq/L) in an alkalotic environment (pH greater than 7.45) there is a METABOLIC ALKALOSIS. On the opposite side of the coin, if there is a decreased HCO3 (less than 22 mEq/L) in an acidic environment (pH less than 7.35) this will be representative of METABOLIC ACIDOSIS.

    If you need to review the above steps, that is OK. If you understand the above material, let's move on to COMPENSATION!

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