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Arterial Blood Gas Interpretation Calculator

About this Calculator

Understanding the physiological principles behind acid-base balance and interpreting the results based on the provided code is crucial. Here's a step-by-step tutorial on how to use this calculator to analyze acid-base disorders:

Analyzing Acid-Base Disorders Using the Arterial Blood Gas (ABG) Calculator

Step 1: Gather Patient Data

Before using the calculator, collect the following patient data:

  • pH: Indicates the acidity or alkalinity of the blood
  • PaCO₂: Partial pressure of carbon dioxide, reflecting respiratory function
  • HCO₃⁻: Bicarbonate level, indicating metabolic function
  • Sodium (Na⁺), Chloride (Cl⁻), and Albumin: Electrolytes used to calculate the anion gap

Step 2: Input Validation

Ensure that the input values fall within the physiological ranges:

  • pH: 6.8 to 7.8
  • PaCO₂: 15 to 130 mmHg
  • HCO₃⁻: 3 to 45 mEq/L
  • Sodium: 110 to 170 mEq/L
  • Chloride: 70 to 130 mEq/L
  • Albumin: 0.1 to 7 g/dL

Step 3: pH Analysis

  • Acidemia: pH < 7.35
  • Alkalemia: pH > 7.45
  • Normal pH: 7.35 ≤ pH ≤ 7.45

Step 4: Primary Disorders

Metabolic Disorders

  • Metabolic Acidosis: HCO₃⁻ < 22 mEq/L
    • Expected PaCO₂ = (1.5 × HCO₃⁻) + 8
    • Check respiratory compensation
  • Metabolic Alkalosis: HCO₃⁻ > 26 mEq/L
    • Expected PaCO₂ = (0.7 × (HCO₃⁻ − 24)) + 40
    • Check respiratory compensation

Respiratory Disorders

  • Respiratory Acidosis: PaCO₂ > 45 mmHg
    • Acute: HCO₃⁻ ↑ by 1 per 10 mmHg PaCO₂ ↑
    • Chronic: HCO₃⁻ ↑ by 3.5 per 10 mmHg PaCO₂ ↑
  • Respiratory Alkalosis: PaCO₂ < 35 mmHg
    • Acute: HCO₃⁻ ↓ by 2 per 10 mmHg PaCO₂ ↓
    • Chronic: HCO₃⁻ ↓ by 5 per 10 mmHg PaCO₂ ↓

Final Steps

Step 5: Compensation Status

  • Evaluate if compensation is appropriate
  • Check for mixed disorders

Step 6: Anion Gap

  • Calculate: Na⁺ − (Cl⁻ + HCO₃⁻)
  • Correct for albumin if needed
  • Normal range: 8-12 mEq/L

Step 7: Final Interpretation

Combine all findings to form complete assessment

mmHg
mEq/L
mEq/L
mEq/L
g/dL
Optional: Used for corrected anion gap
Primary Disorder
-
Compensation
-
Anion Gap
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