Venous Blood pH Calculator
Calculate venous blood pH using the Henderson-Hasselbalch equation for acid-base assessment
Calculate Venous Blood pH
Normal range: 22-26 mEq/L (venous blood)
Normal range: 41-51 mmHg (venous blood)
Example Calculations
Normal Venous pH
Values: HCO₃⁻ = 24 mEq/L, PaCO₂ = 46 mmHg
Calculation: pH = 6.1 + log₁₀[24 / (0.0308 × 46)] = 6.1 + log₁₀(16.95) = 7.33
Interpretation: Normal venous pH (within 7.31-7.41 range)
Venous Acidosis
Values: HCO₃⁻ = 15 mEq/L, PaCO₂ = 50 mmHg
Calculation: pH = 6.1 + log₁₀[15 / (0.0308 × 50)] = 6.1 + log₁₀(9.74) = 7.09
Interpretation: Venous acidosis (pH < 7.31)
Reference Ranges
Venous Blood pH
7.31 - 7.41
Normal range (more acidic than arterial)
Arterial Blood pH
7.35 - 7.45
For comparison
Bicarbonate (HCO₃⁻)
22 - 26 mEq/L
Venous normal range
Venous PaCO₂
41 - 51 mmHg
Higher than arterial CO₂
Clinical Applications
Acid-Base Assessment
Evaluate acid-base balance using venous samples
Emergency Medicine
Quick assessment when arterial access difficult
ICU Monitoring
Continuous monitoring of acid-base status
Metabolic Disorders
Diagnosis and monitoring of metabolic conditions
Henderson-Hasselbalch Equation
Formula Components
- • pH = 6.1 + log₁₀[HCO₃⁻ / (0.0308 × PaCO₂)]
- • 6.1 = pKa of carbonic acid system
- • 0.0308 = solubility coefficient of CO₂
Clinical Significance
- • Describes buffer system in blood
- • Relates pH to bicarbonate and CO₂
- • Foundation of acid-base physiology
Understanding Venous Blood pH
What is Venous Blood pH?
Venous blood pH measures the acidity or alkalinity of blood returning to the heart. It's typically more acidic than arterial blood due to higher CO₂ content from cellular metabolism and tissue respiration.
Clinical Significance
- •Alternative to arterial blood gas when arterial access is difficult
- •Less invasive procedure for acid-base assessment
- •Reliable for detecting significant acid-base disorders
- •Useful in emergency and critical care settings
Henderson-Hasselbalch Equation
pH = 6.1 + log₁₀[HCO₃⁻ / (0.0308 × PaCO₂)]