CLINICAL PATHWAY FOR ADULT ASTHMA. Clinical Diagnosis of Asthma Variability: – Episodic...

CLINICAL PATHWAYFOR

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

• 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 (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

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 (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

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 SettingCONTINUATION

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 < 40% predicted or

personal best•ABG: paC02 >42mm Hg

Incomplete ResponseWithin 1 hr &/or (+) risk

factors•S/Sx: mild to moderate•PEF or FEV1 40-69%

predicted or personal best•Sa02 not improving

Admit to Hospital-Oxygen

- Inhaled SABA-Systemic (oral or IV)

corticosteroids-Consider adjunct

therapies-Monitor vital signs,

FEV1, PEF saO2

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

Admit to ICU:•Continue inhaled SABA+ inhaled anti-

cholinergic•Consider SQ,IV or IM B2-agonist

•IV steroids•IV aminophylline•Continue oxygen

•Possible intubation/mechanical ventilation

Moderate exacerbation Severe Exacerbation

Individualize decision re: hospitalization

IMPROVE

Discharge Home( see below) 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 SettingCONTINUATION

Admit to Hospital

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.

IMPROVE

Key

• 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 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

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