Peak Flow Meter
Peak Flow Meter
A peak flow meter is a portable, handheld device that measures Peak Expiratory Flow Rate (PEFR) - the maximum speed of expiration. It's an essential tool for monitoring and managing asthma in pediatric patients.
Key Points
- Measures air flow in liters per minute (L/min)
- Typical measurement range: 60-800 L/min
- Best used in children over 5 years old
- Available in low-range and standard-range versions
- Critical for home monitoring of asthma
Types Available
- Mechanical Peak Flow Meters
- Standard range (60-800 L/min)
- Low range (50-400 L/min)
- Digital Peak Flow Meters
- Electronic measurement
- Data storage capability
- Bluetooth connectivity options
Technical Aspects
Device Components
- Mouthpiece (disposable or reusable)
- Measurement scale (usually color-coded)
- Sliding indicator
- Reset mechanism
- Handle grip
Accuracy Factors
- Regular calibration requirements
- Temperature and humidity effects
- Proper cleaning and maintenance
- Device positioning
- Patient technique
Quality Standards
- EN 13826 compliance
- ATS/ERS guidelines adherence
- ISO standards for medical devices
- Accuracy tolerance: ±10%
Usage Guidelines
Proper Technique
- Reset indicator to zero position
- Stand or sit upright
- Take a deep breath
- Form tight seal around mouthpiece
- Blow out as hard and fast as possible
- Record the reading
- Repeat 3 times
- Record highest value
Best Practice Guidelines
- Measure twice daily (morning and evening)
- Record values in asthma diary
- Clean device regularly
- Replace annually or as recommended
- Keep consistent measurement time
Result Interpretation
Zone System
- Green Zone (80-100% of personal best)
- Airways are clear
- Continue regular medication
- Yellow Zone (50-80% of personal best)
- Airways are narrowing
- Caution needed
- Follow action plan
- Red Zone (below 50% of personal best)
- Medical emergency
- Immediate action required
- Seek medical attention
Determining Personal Best
- Record readings for 2-3 weeks when well
- Take readings at same time daily
- Highest consistent reading is personal best
- Update every 6-12 months
- Adjust zones based on personal best
Clinical Applications
Diagnostic Uses
- Asthma monitoring and management
- Exercise-induced bronchospasm assessment
- Response to bronchodilator therapy
- Identification of asthma triggers
Clinical Pearls
- Consider diurnal variation
- Account for growth in pediatric patients
- Factor in concurrent medications
- Document technique education
- Regular review of patient technique
Limitations
- Effort-dependent measurement
- Age restrictions (typically >5 years)
- Coordination requirements
- Not suitable for all respiratory conditions
