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metered dose inhaler (MDI)

Device for delivering a measured amount of inhaled pharmaceutical agent to the lungs. Procedure: proper use of metered dose inhaler (MDI) 1) remove cap & hold inhaler upright 2) shake thoroughly 3) tilt head back slightly & exhale steadily to functional residual capacity 4) position the inhaler 4 cm in front of the open mouth, or use a spacer between the actuator & the mouth 5) press down on the inhaler while taking a slow deep breath (3-5 seconds) 6) hold the breath at full inspiration for 5-10 seconds to allow the medication to reach deeply into the lungs 7) repeat inhalations as directed 8) wait 1 minute after inhalation before repeating; may permit deeper penetration into the lungs & ensure proper delivery of dose 9) rinse mouth out & expectorate after using inhaler Also dry powder inhalers (may be easier to use than MDI) [2], but are not more effective [3]. Different types: 1) turbohaler 2) diskhaler 3) Chlorofluorocarbon (CFC) 4) HydroFluoroAlkane (HFA) - softer spray than CFC - wash actuator with warm water weekly to prevent clogging [6] * Ref 2 claims diskhaler more difficult to use. * fluorocarbon inhalers have carbon footprints 20-30 times those of dry powder inhalers [12] 'Float Test' unreliable to determine if MDI is full [4] Counting puffs & carrying spare recommended Doser device counts puffs. Doesn't work with Atrovent, Intal or Tilade [4,6] Ventolin has dose counter [6] Propellant inhalers are overfilled and will spray long after an accurate dose can be ensured. [6] When used* for delivering beta-2 adrenergic receptor agonist, more effective than nebulizer for reducing hospitalization in children with asthma [5] * used with spacer children may not be able to perform maximum inhalation; 2-3 normal inhalations inhale as much aerosolized medication through a spacer as more inhalations [8] patients use inhalers incorrectly ~1/3 of the time [9] up to 90% of patients use their inhalers incorrectly [10]; correct inhaler use may reduce asthma exacerbations & COPD exacerbations [10] in-hospital training on inhaler-use techniques for patient hospitalized with COPD exacerbation can improve inhaler technique at hospital discharge [11]

Related

albuterol (Salbutamol, Ventolin, Proventil) albuterol/ipratropium (Combivent, DuoNeb) formoterol (Foradil, Perforomist) inhaled anticholinergic agent inhaled glucocorticoid salmeterol (Serevent, Serevent Diskus) terbutaline (Brethine, Bricanyl, Brethaine)

General

device (medical device)

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 18. American College of Physicians, Philadelphia 1998, 2018
  2. Journal Watch 21(9):71, 2001 Diggory P et al Comparison of elderly people's technique in using two dry powder inhalers to deliver zanamivir: randomised controlled trial. BMJ 322:577, 2001 PMID: 11238150
  3. Journal Watch 21(24):193, 2001 Ram FS et al, Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering beta (2 )agonists bronchodilators in asthma. BMJ 323:901, 2001 PMID: 11668134 Brocklebank D et al Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering corticosteroids in asthma. BMJ 323:896, 2001 PMID: 11668133
  4. Prescriber's Letter 10(1):6 2003 Prescriber's Letter 12(3): 2005
  5. Journal Watch 24(19):154, 2004 Castro-Rodriguez JA, Rodrigo GJ. beta-agonists through metered-dose inhaler with valved holding chamber versus nebulizer for acute exacerbation of wheezing or asthma in children under 5 years of age: a systematic review with meta-analysis. J Pediatr. 2004 Aug;145(2):172-7. PMID: 15289762 - Smyth RL, Jones A. Treatment of acute wheezing episodes in young children. J Pediatr. 2004 Aug;145(2):151-2. No abstract available. PMID: 15289758
  6. Prescriber's Letter 13(10): 2006 Tips for Correct Use of Metered Dose Inhalers (MDIs) Detail-Document#: 221007 (subscription needed) http://www.prescribersletter.com
  7. Prescriber's Letter 15(8): 2008 PATIENT HANDOUT: How to Use Your Spacer Device CHART: Choosing a Spacer Device For MDIs Detail-Document#: 240809 (subscription needed) http://www.prescribersletter.com
  8. Schultz A et al. Aerosol inhalation from spacers and valved holding chambers requires few tidal breaths for children. Pediatrics 2010 Dec; 126:e1493. PMID: 21078734
  9. Sanchis J et al. Systematic review of errors in inhaler use: Has patient technique improved over time? Chest 2016 Aug; 150:394 PMID: 27060726 Free Article
  10. Maricoto T, Monteiro L, Gama JMR et al. Inhaler technique education and exacerbation risk in older adults with asthma or chronic obstructive pulmonary disease: A meta-analysis. J Am Geriatr Soc 2019 Jan; 67:57 PMID: 30291745 https://onlinelibrary.wiley.com/doi/full/10.1111/jgs.15602
  11. Grandmaison G et al. An in-hospital intervention to reduce the proportion of misused inhalers at hospital discharge among patients with COPD: A non-randomised intervention study. Swiss Med Wkly 2024 Apr 4; 154:3394. PMID: 38579300 Free article https://smw.ch/index.php/smw/article/view/3394
  12. Tirumalasetty J et al. Greenhouse gas emissions and costs of inhaler devices in the US. JAMA 2024 Sep 24; 332:1017-1019. PMID: 39207797 https://jamanetwork.com/journals/jama/fullarticle/2822997 - Janson C et al. Carbon footprint impact of the choice of inhalers for asthma and COPD. Thorax 2020 Jan; 75:82. PMID: 31699805 PMCID: PMC6929707 Free PMC article https://thorax.bmj.com/content/75/1/82