CLINICAL PATHWAY
FOR
ADULT ASTHMA
Clinical Diagnosis of Asthma
• Variability:
– Episodic breathlessness, wheezing, cough, chest
tightness
– Precipitation by allergens or non-specific irritants”
e.g. smoke, fumes, strong smells or exercise
• Nocturnal worsening of symptoms
• Positive family history of asthma & atopic
disease
• Response to appropriate asthma therapy
Physical Examination Findings in
Asthma
• Most usual abnormal PE finding:
– Wheezing on auscultation – confirms presence of
airflow limitation
• PE:
– May be normal – because asthma symptoms are
variable
– Wheezing detected only on forced exhalation
– Wheezing may be absent in severe cases due to
severely reduced airflow and ventilation but
usually with other signs
Objective measurements in Asthma
diagnosis
• Rationale:
– Demonstration of reversibility of airflow limitation
enhances diagnostic confidence
– Patients esp. those with long-standing asthma,
frequently have poor recognition of symptoms
and poor perception of severity
– Physicians may inaccurately assess dyspnea and
wheezing
Lung Function Measurement in
Asthma
• Provides an assessment of severity of airflow
limitation, its reversibility and variability
• Provides confirmation of the diagnosis
• Provides complementary information about
different aspects of asthma control
Spirometry in Asthma
• Diagnosis of asthma:
– Degree of reversibility of FEV1 should be >12% and
>200ml from pre-bronchodilator value
• Spirometry:
– Reproducible but effort-dependent
– Pre- & post test lacks sensitivity esp. those on
treatment, so repeated testing at different visits is
advised
– Proper instructions on maneuver must be given
PEF measurement in Asthma
• Important in both diagnosis and monitoring
• Peak flow meters are relatively inexpensive,
portable, plastic and ideal for use in home
settings for day-to-day objective
measurement of airflow limitation
• Can underestimate degree of airflow
limitation particularly in severe cases
PEF measurement in Asthma
• Can be helpful to confirm the diagnosis of
asthma:
– 60 L/min (or 20% or more pre-BD PEF)
improvement after inhalation of a bronchodilator
– A diurnal variation of >20% (with twice daily
readings >10%)
PEF measurement in Asthma
• Can help to improve asthma control esp. in
those with poor perception of symptoms:
– Self-monitoring using a PEF chart
• Can help to identify
environmental/occupational causes of asthma
symptoms:
– PEF daily or several times a day over periods of
suspected exposure to risk factors (at home,
workplace, during exercise or other activities)
Controller Medications
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Inhaled glucocorticosteroids
Long-acting inhaled β2-agonists
Systemic glucocorticosteroids
Leukotriene modifiers
Theophylline
Cromones
Long-acting oral β2-agonists
Anti-IgE
Reliever Medications
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Rapid-acting inhaled β2-agonists
Systemic glucocorticosteroids
Anticholinergics
Theophylline
Short-acting oral β2-agonists
Asthma Exacerbations
• Episodes of progressive worsening of
shortness of breath, cough, wheezing or chest
tightness or some combination of these
symptoms
• Characterized by significant decreases in PEF
or FEV1 which are more reliable indicators of
severity of airflow obstruction than degree of
symptoms
• May range from mild to life-threatening
Severity of Asthma Exacerbations
Mild
Moderate
Severe
Respiratory Arrest
Imminent
Breathless
Walking
Talking
At rest
Talks in
Sentences
Phrases
Words
Alertness
May be agitated
Usually agitated
Usually agitated
Respiratory rate
Increased
Increased
Often >30/min
Accessory muscles &
suprasternal
contractions
Usually not
Usually
Usually
Paradoxical thoracoabdominal movement
Wheeze
Moderate, often only
end-expiratory
Loud
Usually loud
Absence of wheeze
Pulse/min
<100
100-120
>120
Bradycardia
Pulsus paradoxus
Absent <10mmHg
May be present 1025mm Hg
Often present > 25 mm
Hg
PEF after initial BD %
predicted or %
personal best
Over 80%
Approx 60-80%
<60% predicted or
personal best
(<100/min or response
lasts 2 hrs)
PaO2 and/or PaC02
Normal <42 mm Hg
< 42 mm hg
< 60 mm Hg
Possible cyanosis
>42 mm Hg
possible resp failure
Sa02
> 95%
91-95%
<90%
Drowsy or confused
Features of Patients at high-risk for
asthma-related death
• Current use of or recent withdrawal from systemic
corticosteroids
• Emergency care visit for asthma in the past year
• History of near-fatal asthma requiring intubation or
mechanical intubation
• Not currently using inhaled steroids
• Overdependence on rapid acting inhaled β2-agonists,
esp. those with more than one canister monthly
• Psychiatric disease or psychosocial problems, incl. the
use of sedatives
• Noncompliance with asthma medication plan
Management of Asthma Exacerbations
• Treatment of exacerbations depends on:
– The patient
– Experience of health care professional
– Therapies that are the most effective for the
particular patient
– Availability of medications
– Emergency facilities
Treatment of Exacerbations
• The aims of treatment are to:
– Relieve airway obstruction as quickly as possible
– Relieve hypoxemia
– Restore lung function to normal as early as
possible
– Plan and avoidance of future relapses
– Develop a written action plan in cases of future
exacerbations
Management of Asthma Exacerbations
• Primary therapies for exacerbations:
– Repetitive administration of rapid-acting inhaled
β2-agonists
– Early introduction of systemic glucocorticosteroids
– Oxygen supplementation
• Closely monitor response to treatment with
serial measures of lung function
Criteria for Hospitalization
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Inadequate response to therapy within 1-2 hours
Persistent PEF <50% after 1 hour of treatment
Presence of risk factors
Prolong symptoms prior to ER consult
Inadequate access to medical care and
medications
• Difficult home condition
• Difficulty in obtaining transport to hospital in
event of further deterioration
Asthma Exacerbations and
Hospitalization
• Despite appropriate therapy ~10 to 25% of ER
patients with acute asthma will require
hospitalization
• The response to initial treatment in the ER is a
better predictor of the need for hospitalization
than is severity on presentation
• FEV1 or PEF appears to be more useful in
adults for categorizing severity of
exacerbation and response to treatment
Management of Acute Exacerbations: Hospital Setting
Initial Assessment: History, PE, PEF or FEV1, Sa02
PEF or FEV1 >40% predicted
(Mild to Moderate)
•Oxygen to achieve Sa02
>90%
•Inhaled SABA by nebulizer or
MDI with valve holding
chamber up to 3 doses in 1st
hour
PEF or FEV1 <40% predicted
(Severe)
•Oxygen to achieve Sa02 >90%
•High dose inhaled SABA +
Ipratropium by nebulizer or MDI
with valve holding chamber
every 20 min or continuously
for 1 hour
Impending or actual
respiratory arrest
•Intubation and mechanical
ventilation with 100% 02
•Nebulized SABA and
Ipratropium
•Intravenous corticosteroids
•Consider adjunct therapies
Repeat Assessment:
PE, PEF, Sa02, other tests as needed
Admit to hospital intensive care
-see below
Moderate Exacerbation:
PEF or FEV1 -40-69% predicted or
personal best
•PE: moderate symptoms
•Treatment:
•Inhaled SABA every 60 mins
•Oral systemic corticosteroids
•Continue treatment 1-3 hrs
provided there is improvement:
make decision in < 4 hours
Severe Exacerbation:
PEF or FEV1 < 40% predicted or personal best
•PE: Severe symptoms at rest, accessory muscle use,
chest retraction
•History: high-risk for asthma related death
•No improvement after initial treatment
•Treatment:
•Oxygen
•Nebulized SABA+Ipratropium hourly or
continuous
•Oral systemic corticosteroids
•Consider adjunct therapies
Management of Acute Exacerbations: Hospital Setting
CONTINUATION
Moderate exacerbation
Good Response
Response sustained for 1 hr
after last treatment
No risk factors
•S/Sx: no distress, normal PE
•PEF > 70% predicted or
personal best
•Sa02 >90%
Discharge Home
•Continue inhaled SABA
•Continue oral steroids
•Consider initiation of ICS
•Patient education:
-Review medications, including
inhaler technique
-Review/ initiate action plan
-Recommend close medical
follow-up
Discharge Home
( see below)
improve
Severe Exacerbation
Incomplete Response
Within 1 hr &/or (+) risk
factors
•S/Sx: mild to moderate
•PEF or FEV1 40-69%
predicted or personal best
•Sa02 not improving
Individualize decision re:
hospitalization
Admit to Hospital
-Oxygen
- Inhaled SABA
-Systemic (oral or IV)
corticosteroids
-Consider adjunct
therapies
-Monitor vital signs,
FEV1, PEF saO2
Poor Response
Within 1 hr &/or (+) risk
factors
•S/Sx: severe drowsiness,
confusion
•PEF < 40% predicted or
personal best
•ABG: paC02 >42mm Hg
Admit to ICU:
•Continue inhaled SABA+ inhaled anticholinergic
•Consider SQ,IV or IM B2-agonist
•IV steroids
•IV aminophylline
•Continue oxygen
•Possible intubation/mechanical
ventilation
IMPROVE
Criteria for ICU Admission
• Lack of response to initial therapy in ER
• Presence of confusion, drowsiness, other signs
of impending arrest or loss of consciousness
• Impending respiratory arrest:
– PaO2 < 60 mmHg on supplemental oxygen
– PaCO2 > 45 mmHg
Management of Acute Exacerbations: Hospital Setting
CONTINUATION
Admit to Hospital
IMPROVE
Discharge home
•-Continue inhaled SABAs
•Continue oral systemic steroids
•Continue on ICS
•Patient education:
-Review medications, including inhaler technique
-Review/ initiate action plan
-Recommend close medical follow-up
• Before discharge, schedule follow-up appointment
with primary care provider and/or asthma specialist in
1-4 weeks.
Key
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FEV- Forced Expiratory Volume in 1 second
ICS- Inhaled Corticosteroids
PCo2- Partial pressure Carbon Dioxide
PEF- Peak Expiratory Flow
SABA- Short Acting Beta2 agonist
SaO2- Oxygen Saturation
ADDITIONAL PATIENT
EDUCATION
Home Assessment
Management of Asthma Exacerbations:
Home Treatment
Assess Severity
Initial Treatment
Inhaled SABA: up to two treatment 20 min apart of 26 puffs of MDI or nebulizer treatment
Good Response
Incomplete Response
Poor Response
No wheezing or dyspnea
PEF > 80% predicted or personal best
Persistent wheezing & dyspnea
(tachypnea)
Marked Wheezing & dyspnea
•Contact clinician for follow-up
Instructions & further management
•May continue inhaled SABA over 3-4 hrs
for 24-48 hrs
•Consider short course of oral systemic
corticosteroids
PEF 50-79% predicted or personal
best
•Add oral systemic corticosteroids
•Continue inhaled SABA
•Contact clinician urgently (this
day) for further instructions
PEF <50% predicted or personal best
•Add oral systemic corticosteroids
•Report inhaled SABA immediately
•If distress is severe & nonresponsive to initial treatment: call
your doctor AND ambulance
transport
To ER
REFERENCE
• Philippine Concensus Report on Asthma
Diagnosis and Management 2009 by PCCP
Council on Bronchial Asthma
• PREPARED BY:
– Section of Pulmonary Medicine
• COORDINATED WITH:
– Emergency Department