1. What is Predicted Peak Flow?

Predicted Peak Expiratory Flow (PEF) is an estimate of the maximum speed of expiration, used primarily in asthma management and respiratory assessment. It helps establish personalized expected values based on individual characteristics.

2. How Does the Calculator Work?

The calculator uses the peak flow prediction equation:

Where:

• \( Height \) — Height in centimeters (cm)
• \( Age \) — Age in years
• \( -4.46 \) — Adjustment factor for males only

Explanation: The equation accounts for the relationship between height, age, and gender in determining expected peak flow values. Taller individuals typically have higher PEF values, while PEF decreases with age.

3. Importance of Peak Flow Prediction

Details: Knowing predicted PEF values is crucial for asthma management, monitoring respiratory function, detecting early signs of airway obstruction, and assessing response to bronchodilator therapy.

4. Using the Calculator

Tips: Enter height in centimeters, age in years, and select gender. All values must be valid (height > 0, age between 1-120). For females, the -4.46 adjustment is not applied.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal peak flow reading?
A: Normal values vary by individual characteristics. Generally, 80-100% of predicted value is considered normal, 50-80% indicates caution, and below 50% requires medical attention.

Q2: How often should peak flow be measured?
A: For asthma management, typically twice daily - morning and evening, or as directed by healthcare provider. More frequent monitoring during exacerbations.

Q3: What factors can affect peak flow readings?
A: Recent bronchodilator use, respiratory infections, time of day, effort during testing, and proper technique can all influence readings.

Q4: Are there different prediction equations?
A: Yes, various equations exist based on different populations. This calculator uses a commonly accepted formula suitable for general clinical use.

Q5: When should I seek medical help?
A: If readings fall below 50% of personal best, show significant variability, or if symptoms worsen despite medication.