For adults and children over 5 years old, lung (pulmonary) function tests are used to check how well the lungs are working. Poor lung function is a sign that your asthma isn't well controlled. In some cases, lung function tests are also used in asthma emergencies to help your doctor understand the severity of an asthma attack or how well treatment is working.
Lung function tests include:
Peak flow. Your doctor may take a peak flow reading when you come in for a scheduled visit or for emergency treatment during an asthma attack. This test measures how quickly you can breathe out. You may also use a peak flow meter at home to monitor your lung function.
The results of this test are known as peak expiratory flow (PEF). A peak flow test is done by blowing into a mouthpiece as hard and as fast as you can with a single breath (expiration).
Spirometry. During spirometry, you take deep breaths and forcefully exhale into a hose connected to a machine called a spirometer. A common spirometry measurement is forced expiratory volume, which measures how much air you can breathe out in one second.
The results of this test are known as forced expiratory volume (FEV). Spirometry can also measure how much air your lungs can hold and the rate at which you can inhale and exhale.
Nitric oxide measurement. This exam measures the amount of nitric oxide gas you have in your breath when you exhale. High nitric oxide readings indicate inflammation of the bronchial tubes.
- Pulse oximetry. This test measures the amount of oxygen in your blood. It's measured through your fingernail and only takes seconds.
If you and your doctor have worked out an asthma plan, follow its directions at the first sign of an asthma attack.
This generally means taking two to six puffs of a quick-acting (rescue) inhaler to get airway-expanding medication, such as albuterol (ProAir HFA, Proventil HFA, Ventolin HFA, others) and levalbuterol (Xopenex), deep into your lungs. Small children and those who have trouble with inhalers can use a nebulizer. After 20 minutes, you can repeat the treatment one time if necessary. If you continue to wheeze or feel breathless after treatment, visit your doctor or urgent care that day.
If you're having symptoms of a severe asthma attack, such as difficulty speaking because you're so short of breath, use your quick-acting (rescue) medication and get to a doctor's office or urgent care immediately.
Your doctor may recommend that you continue to use quick-acting medication every three to four hours for a day or two after the attack. You might also need to take oral corticosteroid medication for a short time.
If you go to the emergency room for an asthma attack in progress, you'll need medications to get your asthma under immediate control. These can include:
- Short-acting beta agonists, such as albuterol. These are the same medications as those in your quick-acting (rescue) inhaler. You may need to use a machine called a nebulizer, which turns the medication into a mist that can be inhaled deep into your lungs.
- Oral corticosteroids. Taken in pill form, these medications help reduce lung inflammation and get your asthma symptoms under control. Corticosteroids can also be given intravenously, typically to patients who are vomiting or who are experiencing respiratory failure.
- Ipratropium (Atrovent HFA). Ipratropium is sometimes used as a bronchodilator to treat a severe asthma attack, especially if albuterol is not fully effective.
- Intubation, mechanical ventilation and oxygen. If your asthma attack is life-threatening, your doctor may put a breathing tube down your throat into your upper airway. Using a machine that pumps oxygen into your lungs will help you breathe while your doctor gives you medications to bring your asthma under control.
After your asthma symptoms improve, your doctor may want you to stay in the emergency room for a few hours or longer to make sure you don't have another asthma attack. When your doctor feels your asthma is sufficiently under control, you'll be able to go home. Your doctor will give you instructions on what to do if you have another attack.
If your asthma symptoms don't improve after emergency treatment, your doctor may admit you to the hospital and give you medications every hour or every few hours. If you're having severe asthma symptoms, you may need to breathe oxygen through a mask. In some cases, a severe, persistent asthma attack requires a stay in the intensive care unit (ICU).
Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.
Lifestyle and home remedies
All asthma attacks require treatment with a quick-acting (rescue) inhaler such as albuterol. One of the key steps in preventing an asthma attack is to avoid your triggers.
- If your asthma attacks seem to be set off by outside triggers, your doctor can help you learn how to minimize your exposure to them. Allergy tests can help identify any allergic triggers.
- Washing your hands frequently can help reduce your risk of catching a cold virus.
- If your asthma flares up when you exercise in the cold, it may help to cover your face with a mask or scarf until you get warmed up.
Preparing for your appointment
Be prepared for your visit to your doctor so that you can get the most out of your appointment. At each visit:
- Take your asthma action plan with you. If you haven't made one yet, work with your doctor to create one. This plan should discuss how to treat an asthma attack.
- Bring your peak flow meter results and all of your medications.
- Be prepared to discuss your symptoms, and how much your asthma has been bothering you. Often, periodic changes in treatment are needed to keep asthma under control and to prevent asthma attacks.
- Be prepared to demonstrate using your metered-dose inhaler. Improper use can reduce an inhaler's effectiveness.
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. Some good questions to ask your doctor include:
- Do my medications or treatment plan need to be changed?
- What are the signs that I may be about to have an asthma attack?
- What can I take to prevent an asthma attack when my symptoms get worse, or when I'm exposed to my triggers?
- What steps do I need to take to stop an asthma attack in progress?
- When do I need to go to the emergency room or seek other emergency treatment?
- I'm having more heartburn. What can I do to prevent this?
- Is it time for my flu shot? Am I due for a pneumonia shot?
- What else can I do to protect my health during cold and flu season?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
- Have you noticed anything that makes your asthma worse?
- What medications are you taking?
- How and when are you taking them?
- Can you show me how you use your inhaled medication?
- Are you having any problems with your medications?
- Do you know when to call me or go to the hospital?
- Do you have any questions about your asthma action plan?
- Are you having any problems with your asthma action plan?
- Is there anything you want to be able to do that you can't because of your asthma?
Aug. 02, 2019