Medisafe PEAK FLOW METER

DESCRIPTION

A Peak Flow Meter (like those from Medisafe) is a portable, handheld device used to measure how well air moves out of your lungs. It is a vital tool for individuals managing asthma or chronic bronchitis to monitor airway narrowing before symptoms even start.

Device Specifications & Features

The Medisafe Peak Flow Meter is designed for simplicity and accuracy. Here are the key components:

• Measurement Scale: It uses a Wright-McKerrow scale, typically ranging from 60 to 800 L/min (Liters per minute).

• Color-Coded Zone System: It features adjustable red, yellow, and green indicators. These help you categorize your readings based on your “Personal Best”:

  • Green (80-100%): All clear; management is working.

  • Yellow (50-80%): Caution; airways are narrowing.

  • Red (<50%): Medical emergency/danger.

• Universal Mouthpiece: Usually comes with a reusable plastic mouthpiece that can be cleaned easily.

• Internal Piston/Vane: A mechanical spring-loaded system that moves a pointer to your highest achieved flow rate.

How it Works

When you blow into the device, the force of your breath moves a piston against a spring. The distance the piston travels corresponds to your Peak Expiratory Flow (PEF).

The physics behind the measurement can be simplified as the relationship between pressure and flow rate:

Where:

• $Q$ is the volumetric flow rate.

• $A$ is the cross-sectional area of the opening.

• $v$ is the velocity of the air.

Why Use It?

Think of it like a thermometer for your lungs. Just as you check a temperature to see if you have a fever, you check your peak flow to see if your lungs are “inflamed” or constricted.

• Early Warning: It can detect changes in the airways hours or days before you feel wheezy.

• Trigger Identification: Helps you see if certain environments (pollen, pets, cold air) are dropping your numbers.

• Medication Check: Helps you and your doctor see if your “preventer” inhaler is actually doing its job.

Quick Usage Guide

1. Zero it out: Slide the red marker down to the bottom of the scale.

2. Stand up: This allows your lungs to expand fully.

3. Deep breath: Take the deepest breath possible.

4. The “Blast”: Place your lips tight around the mouthpiece and blow out as hard and fast as you can (like blowing out birthday candles).

5. Record: Note the number where the marker stopped. Repeat three times and record the highest of the three.