How Valved Holding Chambers Work



* Financial support for this article provided by Lupin Pharmaceuticals, Inc. 

HC2When attached to a metered-dose inhaler (MDI), a valved holding chamber (VHC) captures the medicated mist as it sprays out, allowing you to inhale the dose at your own speed. The Guidelines for the Diagnosis and Management of Asthma (Expert Panel Report 3) by the National Asthma Education and Prevention Program support the use of VHCs because they help patients – especially young children – use their inhaler more effectively and easily.1

VHCs are available by prescription only.2 Your physician may recommend a specific brand, or you may choose one from an allergy or medical supply company.

When considering different VHC models, think about ease of use and durability, how it will work with your prescribed metered-dose inhaler (MDI), and these features:

Mouthpiece

The mouthpiece should be shaped to allow you to close your lips securely around the opening while you inhale. Most mouthpieces also have caps to protect them and keep them clean.

Valve

The holding chamber’s one-way valve should trap the medication inside and prevent you from exhaling into the chamber.3 The valve seals the chamber completely, opening only when you inhale. It also pulls out large particles of medication too big to get into your lungs and airways, keeping them from settling in the mouth or throat.4

Mask

Using a mask is helpful for children who are unable to close their lips securely around a mouthpiece or who need to take several breaths to inhale the medication fully.5 The size of the mask is usually determined by the size of the patient’s face. The mask must be fitted tightly and softly over the user’s mouth and nose so the medication cannot escape.6 Some masks attach to the mouthpiece; others replace it completely. One new holding chamber features a mask with a slot for a pacifier for young children to put in their mouth during treatment, offering comfort during the procedure.7

Holding Chamber

Volume of VHCs vary, but in the United States, most are less than 200 mL.8 An adult can empty a 150-200 mL holding chamber in one breath; for a 2-year-old, it may take 2-3 breaths. Fewer inhalations are required to empty smaller devices, which can be beneficial for young children.9 Consider a see-through chamber; this helps you confirm the MDI is activated properly. You can also see when the device needs cleaning. Consider one with an anti-static chamber to reduce the amount of medication that sticks to chamber walls.10

Audible Inhalation Alert

Inhaling too quickly or forcefully can prevent fine medication particles from reaching the target area of your airways. As a result, some holding chambers are fitted with a whistle to help you monitor the speed of your inhalation. If you hear the whistle, slow down.11

Visual Breath Indicator

Also called an inspiratory flow indicator, the visual breath indicator moves as the user inhales, allowing you to confirm if the medication is being taken.12 It helps you watch the breathing pattern so you can activate the MDI at the right time. You can also count the breaths taken.

MDI Adaptor

This is the opening where you insert your MDI and it should be flexible enough to seal tightly around the inhaler’s mouthpiece. Use a holding chamber that accommodates the inhaler’s plastic actuator, not just the metal canister.

Exhalation Vents

Exhalation vents around the mouthpiece or built into a mask give your breath a way out. It’s important to keep from breathing into the holding chamber because the force of your breath could affect the suspension of the medication and you could lose the dose.

Before using your holding chamber for the first time, pull out the instruction sheet and review it carefully. Work with your doctor or nurse to make sure you know how to use it, as well as how to maintain and clean the device properly. It’s worth the time – your lungs will thank you.

For tips on how to use a valved holding chamber, click here


REFERENCES

1) National Heart, Lung and Blood Institute (2007), Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. Retrieved from: http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines/full-report

2) American Academy of Allergy, Asthma & Immunology (2016). Spacers and valved holding chambers (VHCs) for use with metered dose inhalers (MDIs). Retrieved from: https://www.aaaai.org/conditions-and-treatments/library/asthma-library/spacers-asthma.

3) National Heart, Lung and Blood Institute (2007), Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. Retrieved from: http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines/full-report

4) National Heart, Lung and Blood Institute (2007), Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. Retrieved from: http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines/full-report

5) National Heart, Lung and Blood Institute (2007), Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. Retrieved from: http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines/full-report

6) American Academy of Allergy, Asthma & Immunology (2016). Spacers and valved holding chambers (VHCs) for use with metered dose inhalers (MDIs). Retrieved from: https://www.aaaai.org/conditions-and-treatments/library/asthma-library/spacers-asthma.

7) InspiraChamber product. Retrieved from http://www.inspirachamber.com/index.html#top

8) A Guide to Aerosol Delivery Devices for Respiratory Therapists, 3rd Edition (2013). American Association of Respiratory Therapists. Retrieved from https://www.aarc.org/app/uploads/2015/04/aerosol_guide_rt.pdf

9) A Visual Indicator for Inhalation from a Valved Holding Chamber (VHC) is an Important Attribute when Delivering Inhaled Medication to Infants, ResearchGate.net. Retrieved from: https://www.researchgate.net/publication/237523465_A_Visual_Indicator_for_Inhalation_from_a_Valved_Holding_Chamber_VHC_is_an_Important_Attribute_when_Delivering_Inhaled_Medication_to_Infants

10) Valved Holding Chambers and Spacers, American Lung Association. Retrieved from: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/asthma/living-with-asthma/managing-asthma/valved-holding-chambers-and.html

11) Enhancing Asthma Medication Delivers – Spacers and Valved Holding Chambers (2016), NASN School Nurse; S. Schoessler and T. Winders, National Association of School Nurses

12) A Visual Indicator for Inhalation from a Valved Holding Chamber (VHC) is an Important Attribute when Delivering Inhaled Medication to Infants, ResearchGate.net. Retrieved from: https://www.researchgate.net/publication/237523465_A_Visual_Indicator_for_Inhalation_from_a_Valved_Holding_Chamber_VHC_is_an_Important_Attribute_when_Delivering_Inhaled_Medication_to_Infants