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Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator

Easily calculate and compute alveolar-arterial (a-a) oxygen gradient abg calculator with accurate equations, live formulas, and expert guidance.

0.21 = room air.

Calculated Result
14.7 mmHg

A-a Oxygen Gradient

A-a Oxygen Gradient

14.7 mmHg

Alveolar Arterial Gradient Mm Hg

14.7

Alveolar Pao2 Mm Hg

99.7

Expected Age Adjusted Normal

17.8

Pathology Interpretation

Normal A-a Gradient: Hypoxemia likely due to hypoventilation or low ambient FiO2

14.7 — mmHg

Calculation Breakdown

  1. Applied FormulaDifferentiates intrapulmonary causes of hypoxemia (V/Q mismatch, shunt, fibrosis) from extrapulmonary hypoventilation.A\text{-}a = P_A\text{O}_2 - P_a\text{O}_2, \quad P_A\text{O}_2 = F_i\text{O}_2(P_{\text{atm}} - P_{\text{H}_2\text{O}}) - \dfrac{P_a\text{CO}_2}{R}

A-a Gradient Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.03.77.31115A-a Oxygen Gradient

What Is the Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator?

This tool computes alveolar-arterial (a-a) oxygen gradient abg calculator with high precision arithmetic.

How Does the Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator Work?

Differentiates intrapulmonary causes of hypoxemia (V/Q mismatch, shunt, fibrosis) from extrapulmonary hypoventilation.

Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

A-a=PAO2−PaO2,PAO2=FiO2(Patm−PH2O)−PaCO2RA\text{-}a = P_A\text{O}_2 - P_a\text{O}_2, \quad P_A\text{O}_2 = F_i\text{O}_2(P_{\text{atm}} - P_{\text{H}_2\text{O}}) - \dfrac{P_a\text{CO}_2}{R}

Differentiates intrapulmonary causes of hypoxemia (V/Q mismatch, shunt, fibrosis) from extrapulmonary hypoventilation.

How to Use the Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator

  1. Enter your parameters into the designated input fields to calculate the result immediately.

Step-by-Step Example Calculation

Alveolar-Arterial (A-a) Oxygen Gradient ABG Calculator Example

Input Values:

patientAgeYears:55
fractionInspiredOxygen:0.21
arterialPo2:85
arterialPco2:40
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required mmHg.

Factors That Affect the Result

  • Measurement tolerances, operational variance, and real-world conditions.

When Should You Use This Calculator?

  • Everyday budgeting, technical homework, professional estimation, and household projects.

Assumptions & Limitations

  • Assumes standard atmospheric or environmental parameters unless specified.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Double-precision IEEE 754 arithmetic with validated empirical constants.

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