Astham Education Series: Asthma equipment. Part 1: Med delivery systems

As I hinted in my last post in the series, this is going to be a post about all the different gadgets an asthmatic might have. The post will include links and descriptions, but as I have none of the rights to images, I won’t be using them directly here. Instead I’ll link to an article or image of one somewhere else and direct traffic to the person who created the image.

There are a few major categories that I’ll separate everything into just to keep stuff organized and a bit easier to follow: There are medication delivery systems – nebulizers, spacers, metered dose inhalers, dry powder inhalers, and the like. There are at home testing supplies – peak flow meter, pulmonary function testers, and pulse oximeters. There are accessories – specialized ways of carrying around your meds and equipment. Lastly, there are bookkeeping tools for keeping a symptom log – I’ll explore both hardcopy and software options.

This post, for the purpose of length, is going to be split into 3 parts: Medication delivery systems, at-home testing supplies, and accessories and bookkeeping supplies. This is the first part: Medication delivery systems.

What I call a medication delivery system is just a tool that lets you get your meds where they need to be. For people with injected drugs, this would be needles and syringes and suchlike. For asthmatics, they tend to be things that help you inhale stuff into your lungs (although some asthmatics, mostly extremely severe asthmatics, do use auto-injectors and injection pumps, so I’ll include those in this post, too).

The most recognizable medication delivery system is the metered dose inhaler (MDI). MDIs are a way of turning asthma medicine into a mist of fine particles small enough to get into your lungs. A good description of how they work can be found here. In short, the canister contains a mixture of propellant (a liquified, nontoxic and chemically inert gas), medicine, and one or more stabilizers.* The canister is connected to a valve which can only dispense a certain amount of the mixture at a time. When you squeeze the inhaler, the valve is opened briefly and the propellant expands rapidly, forcing the medicine out and into the air as a fine mist, which is then inhaled. Taking an MDI is a bit of an exercise in coordination. Instructions on how to use them properly are provided in detail by reliable medical websites such as Medline, or you can speak with a doctor, nurse, nurse practitioner, respiratory therapist, or pharmacist, all of whom should be able to instruct you in proper inhaler technique. In short, take the cap off, shake the inhaler, hold it about the width of two fingers in front of your mouth, breathe out gently and completely, then squeeze the canister down into the plastic holder as you inhale. Then hold your breath for 10 seconds, and breathe out slowly. It will take some practice to get the hang of the hand-lung coordination.

If you have trouble with taking an MDI properly, or if you are prone to severe attacks, you and your doctor may decide it’s a good idea to add a valved holding chamber or spacer. These are long, hollow, antistatic bubbles or tubes designed to eliminate the hand-lung coordination aspect of MDI use. How to use a spacer varies slightly depending on the design and brand, but typically you insert the MDI into one end, and either put the mask over the face of the person using it (if it has a mask) or put your mouth around the mouthpiece, then the medication is taken as directed by the spacer manufacturer. Spacers tend to be bulky and obvious, so it will usually attract attention and questions if you have or use one.

Let’s say you need a medicine that doesn’t come in a metered dose inhaler, or that you can’t do the breathing necessary to use one, even with a spacer. This is where nebulizers come in. Nebulizers are machines designed to make a mist of your medicine, which you then inhale. Because they tend not to be airtight, they’re not nearly as efficient with the medicine as MDIs or spacers, and as a result, you will have to use more medicine for the same effect. Like with spacers, proper nebulizer use varies a bit from device to device, but if you have one, you can speak to your pharmacist about how to use it. They are fairly straightforward once you know how to set them up, but they’re noisy and time-consuming relative to inhalers.

Next up is dry powder inhalers (DPIs). DPIs are a good alternative for those who don’t like noise or those who find they’re sensitive to propellants or stabilizers (of which I am one – certain brands of rescue puffer have a stabilizer that results in my asthma attack getting worse, not better, so I have to be careful which rescue inhalers I buy). DPIs do not have stabilizers or propellants. Instead they’re use dry, finely ground powder compounded with a bulking agent (usually lactose) contained in a capsule. Using the DPI properly pierces the capsule, and then you inhaling medicine from the inhaler carries it into your lungs. For DPIs to be appropriate for you, you need to be able to make a certain minimum inhalation force because otherwise the powder won’t get carried into your lungs, and so your doctor will usually give you a practice unit which will make noise when you inhale properly. If you’re unable to inhale strongly enough, DPIs are not an option for you.

The last two medication delivery devices are relatively rare for asthmatics. They are infusion pumps and auto-injectors. Infusion pumps for asthma are only used by those with very severe asthma, who need a constant supply of bronchodialator drug (often salbutamol or terbutaline) in their blood system. Often, they use subdermal infusion pumps similar to those used by people with diabetes. I’ve never been severe enough to need one, so I don’t know what they’re like, but they come with many of the same hazards of an insulin infusion pump, and hygiene is very important to avoid infection. Auto-injectors are used by those asthmatics who are prone to status asthmaticus and anaphylaxis. These auto-injectors are exactly the same as those used to treat severe allergic reaction and use the exact same drug (epinephrine) because in many cases, severe asthma attacks are severe allergic reactions. Information on how to use these auto-injectors properly is available from any manufacturer or first aid course.

That’s pretty much it for medication delivery devices for asthma. I haven’t covered any of the out-of-date and obsolete forms of asthma medication delivery devices, though I might examine that history in a later post. In my next post of this series, I’ll talk about home testing devices.


*As an aside, a lot of MDIs contain ethanol as a stabilizer, and this has been known to cause false positives on breathalyzer tests when the breathalyzer is performed shortly after taking your inhaler.

The previous post in this series is here.
The next post in this series is here.

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2 thoughts on “Astham Education Series: Asthma equipment. Part 1: Med delivery systems

  1. […] previous post in this series is here. The next post in this series is […]

  2. […] The previous post in this series is here. The next post in this series is here. […]

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