INTRODUCTION — Inhaled medications are the cornerstone of asthma therapy, but they can only be effective if they are used properly. Correct technique delivers the medication more effectively and leads to better airway responses.The result of poor technique is that little or no medicine reaches the lungs.
Unfortunately, many people with asthma do not use the best inhaler technique. However, studies have shown that almost everyone can learn proper inhaler technique with adequate training and practice.
METERED DOSE INHALERS — Metered dose inhalers (MDIs) are used to deliver a variety of inhaled medications, including quick relief bronchodilators such as Proventil®, Ventolin®, or Alupent®, and controller medicines such as corticosteroids (Flovent®, QVAR®, Pulmicort®, and others) and cromolyn (Intal®). Medications are delivered by pushing down on a canister to release a specific amount of aerosolized medication. An MDI consists of a pressurized canister, a metering valve and stem, and a mouthpiece actuator (show figure 1).
The canister contains the drug suspended in a mixture of propellants, surfactants, preservatives, flavoring agents, and dispersal agents. The propellant has traditionally been a chlorofluorocarbon (CFC). Since the development of an international agreement to ban CFCs, new CFC-free propellants have become available, which use hydrofluoroalkane (HFA) instead of CFCs. Patients who previously used CFC devices should be aware that HFA devices may have a different feel or taste compared to their old device. However, this does not mean the medicine is not reaching their lungs.
COMMON INHALER MISTAKES — Only a portion of the medicine sprayed out of any MDI successfully reaches the lungs, even when used properly. Three common problems can further decrease the efficiency of the device and the delivery of inhaled medications: The medication is sprayed out faster than the patient can breathe it in. The patient inhales before finishing the spray of medication. The patient inhales after the medication is sprayed.
Other common mistakes include inhaling through the nose instead of the mouth, squeezing the canister twice but only inhaling once, and forgetting to take the cap off the mouthpiece.
With inhaled corticosteroids, poor technique may also increase the risk of hoarseness and fungal infection (thrush). For this reason, patients are advised to rinse their mouth with water or brush their teeth and tongue after using inhaled steroids.
For people who have persistent difficulty timing their breath with spraying the medication, there are MDIs available that automatically release the medication when the person breathes in (ie, Maxair Autohaler®).
Another alternative patients may discuss with their healthcare provider is the use of dry powder inhalers (DPIs). DPIs eliminate the need to coordinate inhalation and hand movement. DPIs deliver a fine powder to the lungs when the patient breathes in (show figure 3). Patients who use dry powdered inhalers need to inhale more forcefully than is necessary with a traditional aerosol inhaler. Thus, DPIs may not be suitable for the elderly or persons with nerve or muscle weakness. Also, patients must take care not to blow (exhale) directly into the device before breathing in, as this can scatter the medicine before it can be inhaled.
SPACER DEVICES — Medication delivery can be improved by adding a spacer device to the inhaler. A spacer holds the medicine in a chamber after it has been released from the canister, allowing the patient to inhale slowly and deeply once or twice (show figure 2). Spacers can dramatically decrease the amount of medicine deposited in the back of the mouth or on the tongue, allowing much more of the medicine to reach the lungs.
There are many spacers on the market, although little is known about the benefit of one type versus another. In general, larger sized spacers appear to be more effective than smaller ones. Proper technique and frequent cleaning are important to ensure optimal drug delivery. The package insert that comes with the spacer should be read carefully for specific directions about cleaning and use.
Cleaning the spacer — Although the powder residue that is deposited in the chamber is not harmful, it is recommended that the spacer be cleaned periodically. The spacer should be washed with warm water and dishwashing detergent; washing with water alone causes an electrostatic charge to develop, reducing the effectiveness of the spacer.
TECHNIQUE — When using a metered dose inhaler (with or without a spacer): Shake the inhaler for five seconds If using a spacer, place the mouthpiece of the inhaler into the small end of the spacer Position the inhaler with the index finger on the top of the medication canister and the thumb supporting the bottom of the inhaler Place the spacer tube or mouthpiece between the lips Close mouth around spacer or mouthpiece (show figure 4). For spacers that have a mask, hold the mask snugly to the face Exhale normally (not forcefully) Press down the top of the medication canister with the index finger to release the medication At the same time as the canister is pressed, inhale deeply and slowly until the lungs are completely filled; this should take four to six seconds Hold the medication in the lungs for 4 to 10 seconds before exhaling Wait a minimum of 15 seconds before repeating these steps for a second puff Rinse the mouth after using an inhaled steroid, and spit the water out rather than swallowing it
ASTHMA ATTACK CARE AND PREVENTION — Patients with asthma should work with their healthcare provider to ensure that their medication regimen is successful for both treating and preventing asthma attacks. Depending upon the severity of a patient's asthma, the treatment plan may include regular visits with the provider, use of one or more medications, avoiding asthma triggers, and/or home peak flow monitoring. At each visit, patients should demonstrate how they use an inhaler to their healthcare provider to ensure that the correct technique is used. (See "Patient information: Overview of managing asthma" and see "Patient information: How to use a peak flow meter" and see "Patient information: Trigger avoidance in asthma").
Ensuring medication is available — Patients should always have an adequate supply of their medication(s). This includes verifying that medication is not expired and that a spare MDI is available.
Determining when an inhaler is empty — It is not always possible to determine when an MDI canister is empty by shaking it, because some propellant remains in the canister after all of the medication has been used. A few MDIs are now being manufactured with integrated dose counters, including Ventolin-HFA®, available in the United States since June 2006. In the absence of a counter, patients may maintain a log of the number of sprays used. The MDI should be disposed of when the designated number of sprays has been reached, even if it is still possible to continue spraying. In the past, patients have been instructed to drop the canister into a bowl of water and observe how it floats. However, studies have determined that this method is not reliable and it is no longer recommended.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
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Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Schecker, MH, Wilson, AF, Mukai, DS, et al. A device for overcoming discoordination with metered-dose inhalers. J Allergy Clin Immunol 1993; 92:783.
2. Toogood, JH. Helping your patients make better use of MDIs and spacers. J Respir Dis 1994; 15:151.
3. Melani, AS, Zanchetta, D, Barbato, N, et al. Inhalation technique and variables associated with misuse of conventional metered-dose inhalers and newer dry powder inhalers in experienced adults. Ann Allergy Asthma Immunol 2004; 93:439.
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