1. What is Peak Expiratory Flow Rate (PEFR)?

Peak Expiratory Flow Rate (PEFR) is a measurement of how fast a person can exhale air from their lungs. It is commonly used to monitor and manage asthma and other respiratory conditions. The predicted values help establish personal best readings and track changes in lung function.

2. How Does the Calculator Work?

The calculator uses the EU scale PEFR prediction equation for males:

Where:

• \( \text{Height} \) — Height in centimeters (cm)
• \( \text{Age} \) — Age in years
• 5.48 — Height coefficient
• 0.041 — Age coefficient
• 4.46 — Constant adjustment factor

Explanation: This equation calculates the predicted peak expiratory flow rate based on height and age using the European scale reference values for adult males.

3. Importance of PEFR Prediction

Details: Knowing predicted PEFR values helps in assessing lung function, monitoring respiratory conditions like asthma, evaluating treatment effectiveness, and detecting early signs of respiratory deterioration.

4. Using the Calculator

Tips: Enter height in centimeters and age in years. All values must be valid (height > 0, age between 1-120). This calculator provides predicted values for adult males using the EU scale reference equation.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal range for PEFR?
A: Normal PEFR varies by age, height, and gender. Generally, 80-100% of predicted value is considered normal, while values below 80% may indicate airflow limitation.

Q2: How often should PEFR be measured?
A: For asthma monitoring, typically twice daily - morning and evening. More frequent measurements may be needed during exacerbations or when adjusting medications.

Q3: What factors can affect PEFR readings?
A: Respiratory infections, asthma attacks, COPD exacerbations, poor technique, equipment issues, and recent smoking can all affect PEFR measurements.

Q4: Are there different prediction equations?
A: Yes, different scales exist (EU, US, Asian) with varying coefficients. This calculator uses the EU scale equation specifically for adult males.

Q5: When should I seek medical attention based on PEFR?
A: Seek medical help if PEFR drops below 50% of personal best, shows significant daily variation (>20%), or if you experience worsening respiratory symptoms.