Download The use of inhaler devices in children

The use of inhaler devices in
children
‫د هالة الرفاعي‬
• INTRODUCTION
• The pressurized metered dose inhaler (pMDI) has been
a mainstay in the
• treatment of respiratory diseases, especially asthma,
since its introduction in 1956. It is the most
• commonly prescribed delivery system for administering
inhaled bronchodilators and antiinflammatory
• agents worldwide
• Spacer devices, when used properly, substantially
improve the delivery of
• pMDIgenerated
• aerosols to the distal airways. The pMDI, used
alone or in combination with a spacer or
• valvedholding
• chamber, is the most convenient and
costeffective
• way to administer aerosolized
• medications for most patients.
• Dry powder inhalers (DPI) are a separate group of
medication aerosolizing devices widely used in the
• management of adult and pediatric pulmonary disease.
These devices eliminate the need for propellants,
• and are less dependent upon coordination of
inhalation and device actuation. Shortand
• longacting
• beta
• agonists and inhaled glucocorticoids are available for
administration via DPIs.
• The effectiveness of both delivery systems is
dependent upon several factors, including the
properties of
• the agent administered, design, temperature,
humidity, and patient technique
• Device technique
• should be assessed during every encounter to
ensure optimal use and drug delivery to the
lungs
• Propellants — Up to 80 percent of the aerosol
generated by a pMDI is propellant, historically
a
• chlorofluorocarbon (CFC) such as freon. The
cold blast resulting from the impact of
particles in the
• pharynx (the coldfreon
• effect) when pMDIs containing CFC were
actuated directly into the mouth
• The international ban on CFCs (the Montreal
Protocol) and the disadvantages described above
prompted
• the development of other propellants, such as
hydrofluoroalkanes (HFA), for use with pMDIs. In
some
• cases (such as with HFA beclomethasone ), the
use of HFA improves the delivery of drug to the
lower
• airways and decreases deposition in the
oropharynx
• Similarly, the output of respirable particles
• from an HFAalbuterol
• pMDI is superior to that from a pMDI
containing CFCalbuterol
• when both are
• administered using a spacer device
• Improved delivery to peripheral airways may
necessitate the
• reduction of drug dose, particularly when
using an inhaled glucocorticoid
• Plastic spacers have electrostatic charges within
the chamber that attract particles and
significantly
• reduce drug delivery to the lungs
• This effect may be particularly important when
starting
• bronchodilator therapy in acute asthma. One
option is to use a nonelectrostatic metal spacer,
where
• available
• Alternatively, the electrostatic charge within the plastic
spacer can be reduced by
• washing the spacer in a dilute solution
• Valvedholding
• chambers — The valvedholding
• chamber is a specialized spacer that incorporates a
• oneway
• valve that permits aerosol removal from the chamber
during inhalation and holds particles in the
• chamber during exhalation
• These devices can be fitted with a mouthpiece
or a sizeappropriate
• facemask, making them suitable for use in
infants and young children. When using a
facemask, it is
• important that it is well sealed and that dead
space volume is minimized to assure optimal
drug delivery
• There is no evidence that adding a spacer
improves drug delivery or efficacy as
compared with a
• correctly used pMDI alone
• but the addition of a spacer does correct for
poor pMDI technique in
• most patients and allows faster resolution of
symptoms in children with acute asthma
• In
• addition, using a spacer markedly decreases
oropharyngeal drug deposition and may
reduce both oral and
• systemic side effects, especially when used
with inhaled glucocorticoids
• The use of a spacer or valved holding chamber
is recommended for all children in whom
proper breath
• Pressurized MDI or nebulizer? — Many clinical
trials and metaanalyses
• indicate that the administration
• of beta agonists via pMDI with spacer is at
least as effective as, and possibly superior to,
delivery of
• medication by jet nebulizer in reversing acute
bronchospasm in infants and children
• In
• addition, patients using a pMDI with spacer
may experience fewer side effects (vomiting,
tremors,
• hypoxemia, tachycardia) as compared with
those using a jet nebulizer
• Pressurized MDIs were equal or superior to
nebulizers in studies of small infants with
bronchopulmonary
• Dysplasia
• wheezy infants between 4 and 12 months of
age and young children with
• moderate to severe asthma
• indicating the appropriateness of bronchodilator
therapy via a pMDI
• and valvedholding
• chamber in all age groups. In young children with
moderate to severe acute asthma,
• the pMDI with valved holding chamber produced
a greater reduction in wheezing and significantly
• decreased the need for admission (33 percent
versus 60 percent) as compared with the jet
nebulizer
• Data suggest that four to six puffs of albuterol by
pMDI and valvedholding
• chamber are therapeutically
• equivalent to 2.5 mg by jet nebulizer
• In addition, the dose of drug delivered via pMDI
with
• valvedholding
• chamber can be readily titrated to clinical effect,
which may decrease side effects and
• reduce cost
• These data have led some authors to suggest
that the pMDI with valvedholding
• chamber should be the preferred method for
administering bronchodilators to infants and
children with
• acute asthma at home, as well as in the
emergency department and hospital
Spacer technique
• In one study, almost half of parents received
• inadequate instruction in spacer use for
infants and young children
• Although most of the parents
• thought the procedure was easy to
understand, errors that affected the efficiency
of medication
• administration were common
DRY POWDER INHALERS
• A dry powder inhaler (DPI) is a breathactuated
• device containing
• micronized drug particles with a mass median
aerodynamic diameter (MMAD) of less than 5
μm that are
• usually aggregated with carrier particles (such
as lactose or glucose) of greater diameter
• Drug is
• delivered to the airways by the inhalation of
air over a punctured drugcontaining
• capsule or blister
• DPIs have several advantages compared with
pMDI that are reviewed in the table
• The clinical effects of drugs administered by
DPI are similar to those administered by
pMDI.
• This is true even when beta agonists are
administered in the treatment of acute
asthma
• There is
• evidence that at least some of these
breathactuated,
• drypowder
• devices (eg, Turbuhaler) actually
• enhance pulmonary deposition of inhaled
glucocorticoids and provide equal
improvement in lung
• function at a lower dose compared with
meterdose
• InhalersIn addition, oropharyngeal side effects
• appear to be less common when
glucocorticoids are delivered by DPI
• Device selection — Shor t and
• Long acting
• beta agonists and inhaled glucocorticoids are
available for
• administration via DPIs. A number of different
types of DPIs are commercially available
• Several factors may influence the efficiency of
drug delivery by DPIs. The age of the child and
presence
• of asthma symptoms affect peak inspiratory
flow
• In addition, the design of the device affects
• the resistance to inspiration and the
inspiratory flow required to aerosolize the
medication
• For instance,
• the Diskus is reliable at both low and high flow
rates
• and may be suitable for use in children as
• young as four years of age and patients with
severely impaired lung function (FEV1 less
than 30 percent
• predicted)
• In contrast, highresistance
• devices, such as the Turbuhaler, require
greater inspiratory
• flow to efficiently aerosolize a high percentage
of the nominal dose, and are not as reliable at
lower
• inspiratory flow rates or in patients with
severe airway obstruction
SUMMARY
• The two main types of inhaler devices used to
administer aerosolized medications are the
• pressurized metered dose inhaler (pMDI) and the
dry powder inhaler (DPI). The effectiveness of
• both delivery systems is dependent upon several
factors, including the properties of the agent
• administered, design, temperature, humidity, and
patient technique. Device technique should be
• assessed during every encounter to ensure
optimal use and drug delivery to the lungs
• Many clinical trials and metaanalyses
• indicate that the administration of beta agonists
via pMDI
• with spacer is at least as effective as, and possibly
superior to, delivery of medication by jet
• nebulizer in reversing acute bronchospasm in
infants and children. In addition, patients using a
• pMDI with spacer may experience fewer side
effects compared with those using a jet nebulizer
• A dry powder inhaler (DPI) is a breathactuated
• device containing micronized drug
• These devices eliminate the need for propellants,
and are less dependent on
• coordination of inhalation and device actuation
• However, relatively high inspiratory
• flow rates are required to deaggregate and
aerosolize the drug
• A dry powder inhaler (DPI) is a breathactuated
• device containing micronized drug
• These devices eliminate the need for propellants,
and are less dependent on
• coordination of inhalation and device actuation
• However, relatively high inspiratory
• flow rates are required to deaggregate and
aerosolize the drug.
‫شكرا الصغائكم •‬