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: Spirometry: 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 Exacerbations Mild Moderate Severe Respiratory Arrest Imminent Breathless Walking Talking At rest Talks in Sentences Phrases Words Alertness May be agitated Usually agitated Drowsy or confused Respiratory rate Increased Often >30/min Accessory muscles & suprasternal contractions Usually not 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 Hg possible 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 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 Severe 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% 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 Poor Response Within 1 hr &/or (+) risk factors S/Sx: severe drowsiness, confusion PEF < 40% predicted or personal best ABG: paC02 >42mm Hg Individualize decision re: hospitalization 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 Admit to Hospital Oxygen Inhaled SABA Systemic (oral or IV) corticosteroids Consider adjunct therapies Monitor vital signs, FEV1, PEF saO2 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 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 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 2-6 puffs of MDI or nebulizer treatment Good Response No wheezing or dyspnea PEF > 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: COORDINATED WITH: Section of Pulmonary Medicine Emergency Department