In this Issue October 2004

• No daily symptoms

• No salbutamol use

• No night-time waking due to asthma

• Morning PEF ≥ 80% predicted

• No exacerbations

• No hospital emergency visits

• No treatment-related adverse effects leading to therapy change

To review the published research go to

Can Guideline-defined Asthma Control Be Achieved?: The Gaining Optimal Asthma ControL Study

(Am. J. Respir. Crit. Care Med. 2004; 170: 832-835)
 

Useful Resource

GINA 
(http://www.ginasthma.com/)

An Empty Metered Dose Inhaler - how do you know?

With the transition of most pressurised metered dose inhalers (MDI) to chlorofluorocarbon (CFC) free formulations, it is timely to review how people with asthma determine whether their MDI is empty.

In a recent study from the Wake Forest University School of Medicine in the USA, almost three quarters of the children and parent’s questioned did not know the number of actuations that were available in their MDI. Furthermore of the 50 children and parents involved in the study, all used their MDI until they could no longer "hear" the medication when actuating.

When measuring MDI depletion under different circumstances in the laboratory, hydrofluoroalkane (HFA) canisters typically had 52% more actuations than the nominal dose and CFC canisters had 86% more.

The study researchers concluded that if patients are not taught to recognise when an MDI is empty, they might continue to use the medication for up to twice the intended duration.

How to recognise when an MDI is empty

Until accurate dose counters are added to MDIs, counting the number of doses administered is the only accurate method with which to tell when the canister should be discarded.

Several “popular” methods for determining whether an MDI was still useful include floating the MDI in water* or listening for contents while shaking.

Neither of these methods provides an accurate measure of the MDI contents and, in particular, MDI canisters should be kept dry to avoid any clogging of the actuating mechanism.

The USA National Heart, Lung, and Blood Institute suggest that the only reliable method for determining the number of doses remaining in a canister is to subtract the number of doses used from the number available.

Other strategies for monitoring MDI use may include noting the date that a preventer medication MDI would need to be replaced based on the dose required or using a dose counter.

With reliever medication MDIs that may only be used occasionally, keeping track of doses may be a challenge. People with asthma and their carers should be educated and encouraged to employ strategies that best suit them to monitor MDI use.

It is vital to note that if your usual reliever medication is not working, immediately seek medical help.

To review the published study go to

How Do Patients Determine That Their Metered-Dose Inhaler Is Empty?
(Bruce K. Rubin and Lolly Durotoye, Chest 2004 126: 1134-1137)

*Accuracy of Float Testing for Metered-Dose Inhaler Canisters
(J Am Pharm Assoc 42(4):582-586)

The Bushfire Season is Here

Whether you live in a bushfire prone area or you are a fire fighter, it is vital that you have your Asthma Action Plan up to date and readily available as we head into the bushfire season. 

Inhalation of smoke may cause a range of respiratory problems, including asthma. A combination of smoke and extreme weather conditions may trigger asthma symptoms such as wheeze, difficulty breathing, chest tightness or cough and cause problems for people with asthma as well as those people who are not normally affected by smoke.

The National Asthma Council recommends that people with asthma should follow their personal Asthma Action Plan and continue taking their medication, especially preventer medication.

If anyone is concerned about the effects of bushfire smoke and their asthma they should see their doctor for a check up. Their doctor can review their Asthma Action Plan in case their asthma symptoms worsen or new symptoms develop.

Fire fighters should take extra special care of their asthma where they may have long and intensive exposure to smoke.

Finally, people who do not normally suffer chest complaints should not hesitate to seek medical assistance if smoke affects their breathing.

Useful Resources

First Aid for Asthma

Asthma Action Plans