Interpreting Acid-Base Disorders

Overview

• Interpretation of acid-base disorders involves a three-step process.
• Acid-base lab values include pH, PCO2, and HCO3 (bicarbonate).

Steps to Interpret Acid-Base Disorders

Step 1: Evaluate pH

• Normal range: 7.35 to 7.45
  • Acidosis: pH < 7.35
  • Alkalosis: pH > 7.45

Step 2: Evaluate PCO2

• Normal range: 35 to 45 mmHg
• Determine if PCO2 is moving in the opposite direction of pH:
  • If yes, indicates a respiratory disorder:
    • Respiratory Acidosis
    • Respiratory Alkalosis
• PCO2 and pH move in opposite directions in respiratory disorders.
• If PCO2 is normal or moving in the same direction as pH, proceed to Step 3.

Step 3: Evaluate HCO3 (Bicarbonate)

• Normal range: 22 to 26 mmHg
• Determine if HCO3 is moving in the same direction as pH:
  • If yes, indicates a metabolic disorder:
    • Metabolic Acidosis
    • Metabolic Alkalosis

Recap

• Determine whether pH indicates acidosis or alkalosis.
• Check if PCO2 moves in the opposite direction of pH for respiratory disorders.
• Consider HCO3 for metabolic disorders if PCO2 is normal or moves in the same direction as pH.

Additional Resources

• Visit Picmonic.com for more learning resources that offer visual aids to help remember these processes.