Overview
Asthma is a disease in which inflammation of the airways causes airflow into and out of the lungs to be restricted. When an asthma attack occurs, mucus production is increased, muscles of the bronchial tree become tight, and the lining of the air passages swells, reducing airflow and producing the characteristic wheezing sound.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Led by Dr. Jonathan Pulchalski, a patient undergoes bronchial thermoplasty for the treatment of persistent asthma in the bronchoscopy suite in the Yale New Haven Hospital. This innovative procedure is only one of the many available treatment options that asthma sufferers may be advised to pursue at the YCAAD.
About
Bronchial Thermoplasty
Bronchial thermoplasty is an innovative, new, non-drug procedure developed for the treatment of severe persistent asthma. Bronchial thermoplasty delivered by the Alair® System uses thermal energy to reduce the muscle associated with airway constriction in asthma patients. Clinical studies of this treatment have demonstrated sustained improvements in asthma control up to a year following the treatment. Treated patients not only enjoyed improved asthma-related quality of life for the year following treatment but also fewer severe asthma attacks, fewer visits to the emergency room for respiratory symptoms, and fewer days lost from work/school or other daily activities due to asthma symptoms.
Overview of Bronchial Thermoplasty Procedure
Bronchial thermoplasty delivered by the Alair® System is performed under direct visualization through the working channel of a standard flexible bronchoscope that is introduced through a patient’s nose or mouth and into their lungs. The tip of the small diameter Alair® catheter is expanded to contact the walls of targeted airways reachable by the bronchoscope. Controlled thermal energy then is delivered to the airway walls to reduce the presence of airway smooth muscle that narrows the airways in patients with asthma.
Bronchial thermoplasty is performed in a bronchoscopy/ endoscopy suite and takes about an hour to complete. The minimally invasive procedure, like many other flexible endoscopy procedures, is done under moderate sedation. No
incision is necessary. Post-procedure, patients typically are observed and monitored for approximately 2-4 hours.
There is an expected transient increase in the frequency and worsening of respiratory-related symptoms immediately following bronchial thermoplasty. These events typically occur within one day of the procedure and resolve within seven days, on average, with standard care. An overnight hospital stay may be appropriate in the event of worsening asthma symptoms after the procedure.
Animation of Bronchial Thermoplasty (BT) with the Alair® System
The Alair® Bronchial Thermoplasty (BT) System is the first device-based asthma treatment approved by the FDA and has been shown to help adults with severe asthma gain better control of their disease.
BT uses a small, flexible tube (a bronchoscope), that is inserted through the mouth or nose and guided into the lungs. When the bronchoscope reaches the desired airway, a catheter applies controlled energy to the airway wall to reduce the amount of excess airway smooth muscle. A reduction of airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks and improving patients quality of life.
A typical BT treatment session lasts less than an hour to complete and a total of three treatment sessions is required to treat the entire lung.
Bronchodilators are a type of medication that make breathing easier. They do this by relaxing the muscles in the lungs and widening the airways (bronchi).
They're often used to treat long-term conditions where the airways may become narrow and inflamed. This includes:
- asthma – a common lung condition caused by inflammation of the airways
- chronic obstructive pulmonary disease (COPD) – a lung disease that blocks the airways
Bronchodilators may be either:
- short-acting – used as short-term relief from sudden, unexpected attacks of breathlessness
- long-acting – used regularly to help control breathlessness in asthma and COPD
Bronchodilators and corticosteroids
Inhaled corticosteroids are the main treatment for asthma. They reduce inflammation and prevent flare-ups.
However, some people may also benefit from taking bronchodilators. These help to keep the airways open and enhance the effects of corticosteroids.
In people with asthma, long-acting bronchodilators should never be taken without corticosteroids.
In COPD, treatment is given with short or long-acting bronchodilators first. Corticosteroids are then added in some severe cases.
Treatment with corticosteroids and bronchodilators may require the use of separate inhalers. However, increasingly these medications are provided together in a single inhaler.
Types of bronchodilator
The 3 most widely used bronchodilators are:
- beta-2 agonists – like salbutamol, salmeterol, formoterol and vilanterol
- anticholinergics – like ipratropium, tiotropium, aclidinium and glycopyrronium
- theophylline
Beta-2 agonists and anticholinergics are available in both short-acting and long-acting forms. Theophylline is only available as an oral tablet in a long-acting form.
Beta-2 agonists
Beta-2 agonists are used for both asthma and COPD, although some types are only available for COPD. They're usually inhaled using a small, hand-held inhaler. They may also be available as tablets or syrup.
For sudden, severe symptoms they can also be injected or nebulised. A nebuliser is a compressor used to turn liquid medication into a fine mist. This allows a large dose of the medicine to be inhaled through a mouthpiece or face mask.
Beta-2 agonists stimulate receptors called beta-2 receptors in the muscles that line the airways. This causes them to relax and allows the airways to dilate (widen).
They should be used with caution in people with:
- an overactive thyroid (hyperthyroidism) – a condition that occurs when there's too much thyroid hormone in the body
- cardiovascular disease – any disease of the heart or blood vessels
- an irregular heartbeat (arrhythmia)
- high blood pressure (hypertension)
- diabetes – a lifelong condition that causes a person's blood sugar level to become too high
In rare cases, beta-2 agonists can make some of the symptoms and possible complications of these conditions worse.
Anticholinergics
Anticholinergics (also known as antimuscarinics) are mainly used for COPD. A few are also licensed for asthma.
They're usually taken using an inhaler. However, some may be nebulised to treat sudden and severe symptoms.
Anticholinergics cause the airways to dilate by blocking the cholinergic nerves. These nerves release chemicals that can cause the muscles lining the airways to tighten.
They should be used with caution in people with:
- benign prostatic hyperplasia – a non-cancerous swelling of the prostate
- a bladder outflow obstruction – any condition that affects the flow of urine out of the bladder, like bladder stones or prostate cancer
- glaucoma – a build-up of pressure in the eye
In people with benign prostatic hyperplasia or a bladder outflow obstruction, anticholinergics can cause problems urinating.
Glaucoma can get worse if anticholinergic medication unintentionally gets into the eyes.
Theophylline
Theophylline is taken in tablet form.
It's unclear exactly how theophylline works. However, it seems to reduce any inflammation (swelling) in the airways and relaxes the muscles lining them.
The effect of theophylline is weaker than other bronchodilators and corticosteroids. It's also more likely to cause side effects, so is often only used alongside these medicines if they're not effective enough.
Theophylline should be used with caution in people with:
- an overactive thyroid
- cardiovascular disease
- liver problems – like liver disease
- high blood pressure
- stomach ulcers – open sores that develop on the stomach lining
- epilepsy – a condition that affects the brain and causes repeated seizures (fits)
Theophylline may cause these conditions to get worse. In people with liver problems, it can sometimes lead to a dangerous build-up of medication in the body.
Other medicines can also cause abnormal build-up of theophylline in the body. This should always be checked by your doctor.
Elderly people may also need extra monitoring while taking theophylline.
Side effects of bronchodilators
Bronchodilators can sometimes cause side effects, although these are usually mild or short-lived.
The side effects of bronchodilators can vary depending on the specific medication you're taking. Make sure you read the leaflet that comes with your medication to see what the specific side effects are.
Pregnancy and breastfeeding
In most cases, bronchodilators should be taken as normal while pregnant or breastfeeding.
However, speak to your GP if you regularly use bronchodilators and are considering having a baby or think you might be pregnant.
Pregnancy may affect your asthma. This means it's important to continue taking your medication and have it monitored regularly. This will ensure that the condition is controlled.
Interactions with other medicines
Bronchodilators may interact with other medicines. This could affect the way they work or increase your risk of side effects.
Some of the medicines that can interact with bronchodilators (particularly theophylline) include:
- some diuretics – a type of medication that helps remove fluid from the body
- some antidepressants – including monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs)
- digoxin – a medication used to treat arrhythmias
- benzodiazepines – a type of sedative that may be used as a short-term treatment for anxiety or sleeping problems (insomnia)
- lithium – a medication used to treat severe depression and bipolar disorder
- quinolones – a type of antibiotic medication
This isn't a complete list of all the medications that can interact with bronchodilators. Also, not all of these interactions apply to each type of bronchodilator.
You should always read the patient information leaflet (PIL) that comes with your medication. You may be able to find a specific PIL in the MHRA database on GOV.UK.
If in doubt, speak to your pharmacist or GP.