The nurse admits a client in the ED and performs an arterial blood gas. The results are pH: 7.51,  PCO2: 49,  PO2: 85,  and  HCO3: 35.  Which of the following describes this ABG result?


• Partially compensated metabolic alkalosis is correct because there is an increase in pH (alkalosis) and an increase in HCO3 (indicating that the cause has to be metabolic in origin).  

• PCO2 is also elevated, which tells us the lungs are attempting to compensate by retaining CO2 via decreasing respirations (but have not yet fully compensated.)

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 a buildup 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 - Respiratory centers are not stimulated, which leads to hypoventilation and CO2 retention.

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