Philippine Consensus Reporton Asthma
Diagnosis and Management2009
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
• Inhaled glucocorticosteroids• Long-acting inhaled β2-agonists• Systemic glucocorticosteroids• Leukotriene modifiers• Theophylline• Cromones• Long-acting oral β2-agonists• Anti-IgE
Reliever Medications
• 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 ExacerbationsMild Moderate Severe Respiratory Arrest
Imminent
Breathless Walking Talking At rest
Talks in Sentences Phrases Words
Alertness May be agitated Usually agitated Usually agitated Drowsy or confused
Respiratory rate Increased Increased Often >30/min
Accessory muscles & suprasternal contractions
Usually not Usually Usually Paradoxical thoraco-abdominal 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 10-25mm 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 Hgpossible resp failure
Sa02 > 95% 91-95% <90%
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
• 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 SettingInitial Assessment: History, PE, PEF or FEV1, Sa02
PEF or FEV1 >40% predicted•Oxygen to achieve Sa02
>90%•Inhaled SABA by nebulizer or
MDI with valve holding chamber up to 3 doses in 1st
hour
Impending or actual respiratory arrest
•Intubation and mechanical ventilation with 100% 02•Nebulized SABA and
Ipratropium•Intravenous corticosteroids•Consider adjunct therapies
PEF or FEV1 <40% predicted•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
Repeat Assessment: PE, PEF, Sa02, other tasks as needed
Admit to hospital intensive care
Moderate Episode: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 Episode: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
Good ResponseResponse sustained for 1 hr
after last treatmentNo risk factors
•S/Sx: no distress, normal PE•PEF > 70% predicted or
personal best•Sa02 >90%
Poor ResponseWithin 1 hr &/or (+) risk factors•S/Sx: severe drowsiness,
confusion•PEF < 30% predicted or
personal best•ABG: paC02 >45mm Hg•Pa02< 60 mm Hg
Incomplete ResponseWithin 1 hr &/or (+) risk
factors•S/Sx: mild to moderate•PEF >50% but <70%
predicted or personal best•Sa02 not improving
Admit to Hospital
Improved•PEF >70%
•Sustained on meds
Discharge Home•Continue inhaled SABA q 3-4 hrs (or oral B2-agonist or
theophylline)•Continue oral steroids•Patient education
Admit to ICU:•Continue inh SABA+ inh anti-cholinergic
•Consider SQ,IV or IM B2-agonist•IV steoirds
•IV aminophylline•Continue oxygen
•Possible intub ation/mechanical ventilation
Moderate Episode Severe Episode
Not improved within 6-12 hrs
Discharge home Admit to ICU
Management of Asthma Exacerbations: Home Treatment
Assess Severity
Initial TreatmentInhaled SABA: up to two treatment 20 min apart of 2-
6 puffs of MDI or nebulizer treatment
Good Response
No wheezing or dyspneaPEF > 80% predicted or personal best
•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
Incomplete Response
Persistent wheezing & dyspnea (tachypnea)
PEF 50-79% predicted or personal best
•Add oral systemic corticosteroids•Continue inhaled SABA•Contact clinician urgently (this day) for further instructions
Poor Response
Marked Wheezing & dyspnea
PEF <50% predicted or personal best
•Add oral systemic corticosteroids•Report inhaled SABA immediately•If distress is severe & non-responsive to initial treatment: call your doctor AND ambulance transport
To ER