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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

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:

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: Identify Primary Disorders

  • Metabolic Acidosis: HCO₃⁻ < 22 mEq/L
    • Calculate expected PaCO₂: (1.5 × HCO₃⁻) + 8
    • Check for respiratory compensation or additional disorders.
  • Metabolic Alkalosis: HCO₃⁻ > 26 mEq/L
    • Calculate expected PaCO₂: (0.7 × (HCO₃⁻ − 24)) + 40
    • Check for respiratory compensation or additional disorders.
  • Respiratory Acidosis: PaCO₂ > 45 mmHg
    • Acute: HCO₃⁻ increases by 1 for every 10 mmHg increase in PaCO₂.
    • Chronic: HCO₃⁻ increases by 3.5 for every 10 mmHg increase in PaCO₂.
  • Respiratory Alkalosis: PaCO₂ < 35 mmHg
    • Acute: HCO₃⁻ decreases by 2 for every 10 mmHg decrease in PaCO₂.
    • Chronic: HCO₃⁻ decreases by 5 for every 10 mmHg decrease in PaCO₂.

Step 5: Determine Compensation Status

  • Evaluate if the compensation is appropriate based on the expected values.
  • Identify any additional metabolic or respiratory disorders.

Step 6: Calculate Anion Gap

  • Uncorrected Anion Gap: Na⁺ − (Cl⁻ + HCO₃⁻)
  • Corrected Anion Gap: Adjust for albumin if provided.
    • Normal albumin is 4 g/dL. For each 1 g/dL albumin is below 4, add 2.5 to the anion gap.
  • Interpretation:
    • High anion gap (>12) suggests the presence of unmeasured anions, often seen in metabolic acidosis.
    • Normal anion gap indicates no significant unmeasured anions.

Step 7: Interpret Results

Combine the findings from the pH analysis, primary disorder identification, compensation status, and anion gap calculation to form a comprehensive interpretation.

Display the results, including primary disorders, compensation status, and anion gap, to guide clinical decision-making.

By following these steps, healthcare professionals can effectively use the ABG Calculator to analyze acid-base disorders and provide appropriate patient care.

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