Dry Powder Inhalers: You Need to Breathe In “Hard and Fast”to Get the Powder Deep into the Lungs

Dry Powder Inhalers Have Internal Resistances

Background: Inhaled bronchodilators are the cornerstone for treatment of those with COPD. However, it is important that the person be able to inhale the medication deep into the lungs in order to open the airways and make it easier to breathe.

Of the four different inhaling devices for bronchodilators, the most common is called the pressured metered-dose inhaler shown in the figure below. Simply pressing the canister down releases a spray (aerosol) from the mouthpiece.

Example of metered-dose inhaler. This is a different system than dry powder inhalers.

Pressurized metered-dose inhaler.

Many bronchodilators are available in dry powder inhalers (see below). All dry powder devices have an internal resistance. As a result, you need to inhale “hard and fast” to literally pull the powder out of the device and inhale it deep into the lungs.

Different dry powder inhalers

Dry powder inhalers have an internal resistance.

There is a simple breathing test to determine if you have enough inspiratory force to inhale the powder successfully out of the inhaler. This test is called peak inspiratory flow rate (abbreviated PIFR). Here is a picture of the In-Check DIAL used to measure PIFR.

In-Check DIAL to measure the resistance of dry powder inhalers

In-Check DIAL to measure peak inspiratory flow rate

Study: Dr. Loh and colleagues at the Winston-Salem Baptist Medical Center in North Carolina measured PIFR in patients just before discharge from the hospital for a flare-up (exacerbation) of COPD. The study results are published on-line in the Annals of the American Thoracic Society on April 13 (doi: 10.1513/AnnalsATS.201611-903OC).

Results: 52% of the 123 subjects had a PIFR below 60 liters/min. A value of 60 or higher is considered “optimal” to inhale the powder deep into the lungs.   Those with PIFR less than 60 liters/min were more likely to be readmitted to the hospital over 90 days for another COPD flare-up (28%) compared with subjects who had PIFR at least 60 or higher (14%).

Conclusions: The authors concluded that a low PIFR is common in those admitted to the hospital for a COPD flare-up. They recommended that the medical team measure PIFR before discharge, especially if a dry powder is being prescribed.

My Comments: With a PIFR of less than 60, it more likely that some or most of the powder stays in the mouth and throat. IF you are taking a dry powder bronchodilator and IF you find that it does not help you breathe easier, then you should ask your health care provider to measure your PIFR. If an In-Check DIAL is not available to test your PIFR, then you should ask about a different delivery system – possibilities include a pressurized metered-dose inhaler, a soft mist inhaler, or a nebulizer.

Woman inhaling aerosol from nebulizer

Soft mist inhaler

Cleaning Inhalers: Is It Necessary? How do I Clean My Inhalers?

Cleaning Inhalers – Helps to Prevent Infection

Dear Dr. Mahler:

I recently read that I should clean my inhalers to make sure that they work correctly and to prevent infections. However, I can’t find any information that describes how to do this. I use Symbicort inhaler and Spiriva powder every day and ProAir as my rescue inhaler. What do you recommend?

Gerard from San Juan, Puerto Rico

Dear Gerard:

You ask an important question about keeping inhaler devices clean and working properly. Unfortunately, this topic – cleaning inhalers – has not received a lot of attention.

As I am sure that others with COPD have the same question or concern as you do, here is information for cleaning inhalers as well as nebulizers.

Metered-dose inhaler (abbreviated MDI)

Cleaning inhalers is important for metered-dose inhalers

Diagram of metered-dose inhaler

When you press down on the top of the chamber, the aerosol spray comes out of the metering chamber and enters the nozzle  (see above). There is concern that the spray might accumulate over time and clog the nozzle. Cleaning the actuator with running water and air drying is recommended periodically to reduce this possibility.

Dry-powder inhaler (abbreviated DPI)

Dry-powder inhalers

A clean, dry cloth should be used to wipe away any powder from the mouthpiece. This should minimize any contamination with bacterial or fungus. This should be done periodically.

Soft mist inhaler (abbreviated SMI)

Soft mist inhaler

All that is required with the soft mist inhaler is to clean the mouthpiece with a damp cloth. It is recommended that cleaning be performed periodically.

Nebulizer

The main source of nebulizer contamination is the patient. People of all ages tend to drool into the mouthpiece which explains why bacteria are frequently found in the reservoir (cup) after use.

nebulizer is one delivery system in which cleaning inhalers is important.

Hand held nebulizer

Any liquid that remains in the cup after you have finished inhaling leaves a wet environment with potential for growth of bacteria. This has led to the recommendation that the nebulizer be rinsed, washed, and air dried after each use.

Here are specific recommendations: Detach the medicine cup and mouthpiece from the tubing. Wash the medicine cup and mouthpiece with warm soapy water and rinse them with water. Place the equipment on a clean towel to fully air dry. Make sure to do this after each treatment and daily.

  • Don’t wash the tubing. If it gets wet, replace the tubing. Also, don’t put any parts of the nebulizer into a dishwasher to clean it because the heat can warp the plastic. Tubing should be changed periodically, usually every two weeks.

Here is a way to disinfect the mouthpiece and cup every other day. Mix a solution of 1 part distilled white vinegar and 3 parts warm tap water in a clean bowl. Soak the nebulizer parts (except the tubing and mask) for 60 minutes, then rinse thoroughly and air dry.

 

Nebulizer Therapy – Can It Help Me Breathe Easier?

When to Consider Nebulizer Therapy

Dear Dr. Mahler:

I have severe COPD and attend pulmonary rehab sessions at the nearby hospital.  I take Advair in the purple disk twice a day and Spiriva powder in the capsule each morning. One of the other patients at rehab told me that she uses medicines in a nebulizer machine and this helps her breathe much better than when she used different inhalers in the past. Do you think that nebulizer therapy might help me?

Tracy from Bellingham, WA

Dear Tracy,

There are four different delivery systems for inhaled medications to treat those with COPD: metered-dose inhalers (commonly called puffers); dry powder inhalers; soft mist inhalers; and nebulizers. Some examples are shown below. In general, pharmaceutical companies have mainly been developing new bronchodilator medications as dry powders.

Metered-dose Inhaler

Metered-dose Inhaler

Examples of dry-powder inhalers

Examples of dry-powder inhalers

With dry powder inhalers, you need to take a hard and fast breath in – in order to pull the powder out of the device and overcome its internal resistance. Some individuals, especially those with more advanced COPD, may not have enough strength to successfully break up the powder packet in the inhaler device and then inhale the powder particles deep into the lower parts of the lungs.

Nebulizer therapy is used frequently to deliver bronchodilator medications to those with COPD who are experiencing a flare-up (exacerbation) both in the Emergency Department and in the hospital. Many patients with COPD find that this approach works better because you just breathe in and out normally when inhaling the medications from the nebulizer, and you don’t have to have to hold your breath as you do with the other delivery systems.

Inhaler machine for nebulizer therapy

Hand held nebulizer

There are four major reasons why your health care provider might prescribe nebulizer therapy: you have difficulty using the other inhaler devices [because of arthritis of the hands and wrists or because of difficulty following instructions (dementia)]; you have difficulty coordinating the steps to release the medication from the device, inhaling correctly, and then holding your breath for as long as possible; you are not able to breathe easier with inhaler devices; AND you do not have adequate force when breathing in to pull the powder out of the inhaler.

I suggest that you ask your health care provider whether a trial of nebulizer medications is appropriate, especially since you don’t feel it is easier to breathe with your current inhalers. Both types of bronchodilators (beta-agonists and muscarinic antagonists) as well as an inhaled corticosteroid are available in solutions for use in a nebulizer. These three different types of medications are similar to the Advair and Spiriva dry powder inhalers that you are currently using.

Best wishes,

Donald A. Mahler, M.D.