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The nurse reviews the following arterial blood gases and understands that the patient has which acid-base imbalance?
pH 7.49, PCO2 41, HCO3 38

Explanation

•Uncompensated metabolic alkalosis is correct because there is an increase in pH (alkalosis), increase in HCO3 (metabolic in origin), and PCO2 is normal (this tells us the lungs are not compensating).

Respiratory Acidosis:
•Respiratory system is the cause
•Increase in PCO2, decrease in pH
•Compensation - Kidneys reabsorb Bicarb (HCO3)

Metabolic Acidosis:
•Caused by loss of bicarb or build up of acids - Lactic acidosis, diarrhea, renal failure, ketones, ammonium intoxication. Not caused by respiration.
•HCO3 decreases, pH decreases
•Compensation - hyperventilation to eliminate CO2

Respiratory Alkalosis:
•Caused by excessive ventilation
•Decrease in PCO2, increase in pH
•Compensation - Kidneys excrete HCO3

Metabolic Alkalosis
•Acid (H+) lost from emesis, diuretics. Retention of HCO3 from medications, hyperaldosteronism
•Increase in HCO3, Increase in pH
•Compensation - Repiratory centers are not stimulated, this leads to hypoventilation and CO2 retention

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