How to Calculate Arterial Blood pH

The Arterial Blood pH Calculator estimates the acidity (pH) of arterial blood using the Henderson-Hasselbalch equation, which is based on bicarbonate (HCO₃⁻) and arterial carbon dioxide partial pressure (PaCO₂). The formula used is:

Where:

• \( [\text{HCO}_3^-] \): Bicarbonate concentration in the blood (in mEq/L or mmol/L, normal range: 23-30 mEq/L).
• \( \text{PaCO}_2 \): Partial pressure of carbon dioxide in arterial blood (in mmHg, normal range: 35-45 mmHg).

Enter the bicarbonate and PaCO₂ values to compute the arterial blood pH.

Using the Arterial Blood pH Calculator

This calculator is designed to assist healthcare professionals in assessing acid-base balance and diagnosing conditions such as acidosis or alkalosis by estimating arterial blood pH.

Input the bicarbonate concentration (in mEq/L) and PaCO₂ (in mmHg). The calculator will display the arterial blood pH value and indicate whether it suggests acidosis, alkalosis, or normal pH.

Normal pH Ranges:

• Normal arterial blood pH: 7.35-7.45
• Acidosis: pH < 7.35 (too acidic)
• Alkalosis: pH > 7.45 (too alkaline)

Example: Calculate the pH for bicarbonate = 24 mEq/L and PaCO₂ = 40 mmHg.

1. Bicarbonate: \( 24 \, \text{mEq/L} \)
2. PaCO₂: \( 40 \, \text{mmHg} \)
3. Calculation: \( \text{pH} = 6.1 + \log_{10}\left(\frac{24}{0.03 \times 40}\right) = 6.1 + \log_{10}\left(\frac{24}{1.2}\right) = 6.1 + \log_{10}(20) \approx 6.1 + 1.3010 = 7.401 \)
4. Result: Arterial blood pH ≈ 7.40 (Normal)

Use this tool for quick and accurate pH calculations in clinical settings, but consult a healthcare provider for diagnosis and treatment decisions.