Allergy & Asthma Network Mothers of Asthmatics (AANMA)

What’s Behind That Wheeze?

Published February - 4 - 2009 Print This Post

AANMA takes you deep inside your lungs to understand “when asthma happens . . . .”

Your lungs perform a vital function every day: They feed oxygen to your body and remove waste products with each breath. Most people don’t even notice the important work their lungs are doing – until there’s a problem.
A telltale cough . . . that tight feeling in your chest . . . the whistling wheeze at the end of your breath . . . . These are the familiar outward signs of what we call the noisy part of asthma. Other symptoms of asthma are less obvious but no less serious. The quiet part of asthma includes airway inflammation and swelling – it’s always there, waiting to kick-start symptoms as soon as you run into triggers like pet dander, pollen or smoke.
Knowing what’s actually happening inside your lungs is the first step to getting and keeping your asthma under control. AANMA takes you deep inside your lungs to understand “when asthma happens . . . .”


Follow That Breath
If you could peer all the way down your throat, you’d see that just below your neck, two bronchial tubes (called bronchi) branch off from your windpipe and lead into your lungs. Like a mirror image of a tree that divides into smaller branches as it reaches for the sky, your breathing tubes separate into smaller passageways (called bronchioles) that descend downward, creating an intricate maze in your lungs. Your bronchioles end in hundreds of millions of tiny air sacs called alveoli – this is where oxygen goes in and waste products like carbon dioxide come out of your bloodstream, all to help the rest of your body function.
From bronchi to alveoli, this complex network of airways measures about 1,500 miles. And if you spread all your alveoli flat on the ground, they would cover a tennis court!
How does all of this fit inside your chest?! The first part of your airways is fairly large (which is why we call them your large airways). Then they become very tiny (called small airways), some as thin as a strand of hair – so small that it takes just droplets of sticky mucus or slight swelling to clog them up and interfere with your ability to breathe.
Technically your “airways” start at your nose and end all the way down at your air sacs (alveoli). But asthma is a disease of the lungs, so when your doctor talks to you about airway inflammation and asthma, she generally means the lower half of your respiratory system – starting at the two large bronchi leading into your lungs and ending down in your alveoli.


Layers on the Inside
The inside of your airways is lined with layers of cells called the epithelium – think of it as the skin of your airways. Like the skin on the outside of your body, the epithelium is a barrier against immune system invaders such as allergens, irritants and germs.
Mucus cells in the epithelium squirt a steady supply of mucus to moisturize your airways, keeping them soft and supple. This mucus also traps particles and moves them out of your lungs by riding on top of tiny hair-like projections called cilia. Your cilia create a mucus wave, moving both the mucus and trapped particles into your throat where you either cough it up or swallow it all. (You produce and process about two quarts of the stuff every day!)
Surrounding your airways are strong bands of muscles whose major purpose is to hold breathing passages open. Without these muscles, your airways would collapse and stick together.

asthma-diagram


When Asthma Happens
When asthma symptoms flare, your airways become swollen, mucus backs up and your immune system – trying to battle invading allergens or germs – adds even more fluid to congested breathing passages. With your airways filling up, your bronchial muscles twitch and strain to hold them open.
What happens next is not so much that you can’t inhale, but rather that you can’t fully exhale. Used air gets trapped in the lungs, barely able to get out through the swollen, mucus-filled passageways. As it squeezes through, it makes a wheezing sound.
With trapped air filling your airways, there’s little room for fresh air to get in, but your body instinctively tries to clear the passageways with coughs or force more air inside with rapid, shallow breaths.
Asthma was once considered primarily a disease of the large airways, but research has indicated that very small airways (called distal airways, measuring less than 2 mm in diameter – just double the diameter of a grain of rice!) play an important part in asthma symptoms too, especially in difficult-to-control asthma. These airways are so small and deep inside the lungs that it is hard to measure how well they are functioning. It is also difficult for inhaled medications to penetrate down that far. But you can take steps to help your asthma medication reach as deep as possible into your airways.


Perfect Technique
Using the right technique for your metered-dose inhaler (MDI) or nebulizer is the first step to getting the dose of medication you need. Inhaler technique is the same no matter which MDI medication you’re using: Exhale. Depress the top of the canister as you slowly inhale a full, deep breath. Hold your breath for 10 seconds, then slowly exhale again. Wait a few moments before taking another dose. (The patient instructions that come with your medication will tell you exactly how long to wait between doses.) If you try to take a few quick puffs all together, the medication won’t reach your airways and you could be at risk for more severe asthma symptoms.
Nebulizer technique is important too. Close your lips carefully and securely over the mouthpiece or fit the face mask tightly over your mouth and nose. Keep inhaling until all the medication is gone – approximately 5 to 10 minutes. Talk with your doctor about which nebulizer is right for you and your medication. Some medicines require a specific type of nebulizer. If you are using a mouthpiece, be sure to breathe through your mouth only; pinching your nose shut may help you do that.
Cleaning your inhaler or nebulizer according to the manufacturer’s instructions will keep your equipment in top working condition.


Helpful Holding Chambers
A valved holding chamber can help you inhale medication deep into your airways – and decrease the amount of medication that’s deposited inside your mouth. A valved holding chamber suspends medication from an MDI for a few seconds to give you more time to inhale slowly and deeply so you can focus on your breathing and not on getting your timing just right. You must have a physician write you a prescription for a valved holding chamber.
If you’re using an inhaler with an HFA (hydrofluoroalkane) propellant, it’s important to use a static-free holding chamber to minimize the amount of medication that may get stuck to the inside of the holding chamber.


You Are What You Breathe

Anything you inhale becomes part of your physiology if it makes it past your immune system defenses. For people with allergic asthma, it’s critical to remove allergens and irritants from your environment to reduce your allergy and asthma symptoms and your need for medications. Take simple, no- or low-cost steps like the ones listed in AANMA’s Indoor AIRepair at Home, School and PlayTM kit (available free of charge at www.aanma.org or by calling 800.878.4403) to improve your indoor air quality and avoid overburdening your immune system.


What About That Wheeze?
The goal of your asthma management plan is to keep your lungs healthy and prevent breathing emergencies. By the time you start wheezing, your lung function is severely compromised by inflammation and mucus – you are in the midst of a serious asthma attack that requires time and medication to get under control. So don’t wait for the wheeze! Instead, treat asthma at the first sign of a problem and don’t delay asking for help if symptoms get worse.
Devon Smith knows too well how uncontrolled asthma feels. Devon was a pro at his Backyard BasketballTM video game, but he would tell his dad he couldn’t shoot a game of hoops in the driveway because he was too busy. In reality, running around outside made him short of breath, hurt his chest and caused him to cough and wheeze. Devon finally talked with his parents and medical care team about his symptoms and wrote an Asthma Wish ListTM to set goals for his asthma treatment plan. Now he’s back on the basketball court and giving his thumbs a break from video games!

Author:  Laurie Ross
First published: Allergy & Asthma Today, Spring 2007
Updated February 2009