Dekhuijzen et al. created an algorithm to take patient's inspiratory flow and coordination ability into consideration when selecting inhaler devices:

Is this patient able to generate an adequate inspiratory flow?
e.g. patient with severe hyperinflation in COPD or during asthma attacks
Is this patient able to coordinate device manipulation and inspiratory effort?
e.g. patient with arthritis

Patient		Sufficient inspiratory flow	YES	Coordination OK	YES	Click to see inhaler list with all boxes ticked except Nebuliser
		NO		NO
Click to see inhaler list with all boxes ticked except DPI and Nebuliser	YES	Coordination OK		Click to see inhaler list with all boxes ticked except MDI (without spacer) and Nebuliser
		NO
		Click to see inhaler list with all boxes ticked except MDI (without spacer) and DPI

INHALER LIST
	Metered-Dose Inhaler (MDI)
	Metered-Dose Inhaler (MDI) with spacer
	Dry Powder Inhaler (DPI)
	Breath actuated aerosol
	Soft Mist inhaler
	Nebuliser

Adapted from Dekhuijzen et al., 2013¹
MDI: metered-dose inhaler | DPI: dry powder inhaler

Physicians have an important role in helping their patients to find the device that best fits their needs, in terms of their age, dexterity, inspiratory capacity, cognitive ability, health literacy, and preference.²

Overview of the main characteristics of inhaler devices²
Inhaler type	Pros	Cons
pMDI	Portable and compact Multidose device Metered dose Established/familiar Available for most inhaled medications	Require coordination High deposition in mouth and oropharynx "Cold Freon" effect Contain propellants
pMDI+spacer	Lower dependency on inspiratory effort Easier to coordinate Higher lung deposition than pMDI Reduced mouth and oropharynx deposition	Less portable than pMDI Certain spacers may acquire electrostatic charge Additional cost to pMDI Requires regular maintenance
BA-MDI	Portable and compact Multidose device Breath-actuated	Contain propellants "Cold Freon" effect Requires a moderate inspiratory effort
DPI	Portable and compact Breath-actuated Does not contain propellants Multidose devices available	Requires a minimum inspiratory effort May not be appropriate for emergency situations Multiple designs (may be confusing for the patient) May be complicated to load
SMI	Portable and compact Multidose device Lower dependency on inspiratory effort High fine-particle fraction High lung deposition; low mouth and oropharynx deposition Does not contain propellants	Not breath-actuated Only one device currently available
Nebulizers	Can be used at any age Can be used by acutely ill No specific inhalation technique required Can be used to dispense drugs not available as pMDI or DPI	Most lack portability Some require an outside energy source Can result in longer treatment times Can be expensive

Adapted from Kaplan et al., 2018²
BA-MDI: breath-actuated metered-dose inhaler | DPI: dry powder inhaler
pMDI: pressurized metered-dose inhaler | SMI: soft mist inhaler