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PULMONOLOGY
Bronchodilators
Diagnoses and
assessment
» A clinical diagnosis
»
»
»
of COPD should be
considered in any patient
who has dyspnoea,
chronic cough or sputum
production, and a history
of exposure to risk factors
for the disease.
Spirometry is required
to make the diagnosis
in this clinical context.
The presence of a post-
bronchodilator FEV1/
FVC <0.70 confirms the
presence of persistent air
flow limitation and thus of
COPD.
The goals of COPD
assessment are to
determine the severity
of the disease, including
the severity of air flow
limitation, the impact
on the patient’s health
status, and the risk of
future events (such as
exacerbations, hospital
admissions, or death), in
order to guide therapy.
Comorbidities occur
frequently in COPD
patients, including
cardiovascular disease,
skeletal muscle
dysfunction, metabolic
syndrome, osteoporosis,
depression, and lung
cancer. Given that they
can occur in patients
with mild, moderate and
severe air flow limitation
and influence mortality
and hospitalisations
independently,
comorbidities should be
actively looked for, and
treated appropriately if
present.
» Non-surgical
bronchoscopic lung
volume reduction
techniques should not
be used outside clinical
trials until more data is
available.
8
|
May 2017
Increase the FEV1 or change
other spirometric variables,
usually by altering airway
smooth muscle tone, are
termed bronchodilators.
Bronchodilators improve
emptying of the lungs, tend to
reduce dynamic hyperinflation
at rest and during exercise,
and improve exercise
performance. The extent of
these changes, especially in
severe and very severe patients,
is not easily predictable from
the improvement in FEV.
Bronchodilator medications are
given on either an as-needed
basis or a regular basis to
prevent or reduce symptoms.
Beta 2 -agonists
The principal action of beta 2 -
agonists is to relax airway
smooth muscle by stimulating
beta 2 -adrenergic receptors,
which increases cyclic
adenosine monophosphate
(cAMP) and produces
functional antagonism to
bronchoconstriction. The
bronchodilator effects of short-
acting beta 2 -agonists usually
wear off within four to six hours.
Regular and as-needed use
of short-acting beta-agonists
improve FEV1 and symptoms.
The use of high doses of
short-acting beta 2 -agonists
on an as-needed basis in
patients already treated with
long-acting bronchodilators
is not supported by evidence,
may be limited by side effects,
and cannot be recommended.
For single-dose, as-needed
use in COPD, there appears
to be no advantage in using
levalbuterol over conventional
bronchodilators.
Long-acting inhaled beta 2 -
agonists show duration of
action of 12 or more hours.
Formoterol and salmeterol
significant