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Acute Asthma: 2009 Update

Acute Asthma: 2009 Update. Heather Lemon-Mulé, MD Director, Pediatric Allergy & Immunology St. Barnabas Hospital July 28, 2009. Definition of Asthma. A chronic inflammatory disease of the lungs characterized by reversible airway obstruction and airway hyper-reactivity

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Acute Asthma: 2009 Update

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  1. Acute Asthma:2009 Update Heather Lemon-Mulé, MD Director, Pediatric Allergy & Immunology St. Barnabas Hospital July 28, 2009

  2. Definition of Asthma A chronic inflammatory disease of the lungs characterized by reversible airway obstruction and airway hyper-reactivity Acute asthma exacerbations are paroxysmal episodes of wheeze, cough, tachypnea, dyspnea, hypoxia, respiratory failure

  3. Etiology of Acute Exacerbations Viral agents identified in >80% of pediatric asthma exacerbations and >50% of adult asthma exacerbations Rhinovirus is identified in>65% of wheezing episodes caused by URIs Peaks in hospital admissions for asthma correlate with RV seasons (spring and fall)

  4. Acute Asthma Etiology

  5. Etiology of Acute Asthma Exacerbations Allergen exposure (aeroallergen) Exercise Atypical bacteria GERD Sinusitis ASA/NSAID ingestion (AERD)

  6. Pathophysiology

  7. Pathophysiology: Virus-Induced Wheezing

  8. Pathophysiology of Acute Asthma

  9. Pathophysiology: Virus-Induced Wheezing

  10. RV in Asthma: Innate Immune Defect? Interferons are anti-viral proteins produced in the innate immune response to viral infections IFN-β induces apoptosis in infected cells; decreased production of IFN-β in asthmatics allows increased viral replication Asthmatics also have decreased production of IFN-α and IFN-λ

  11. Allergy and Viral Infections: Synergy? Murray et al (Thorax 2006) showed allergen-exposed, atopic asthmatic children at greater risk for hospital admission with LRT viral infections Similar findings in adult asthmatic patients (BMJ 2002)

  12. Allergen Sensitization and Exposure Exposure to seasonal allergens implicated in sudden asthma-related deaths Alternaria sp exposure is associated with exacerbations and a 200-fold increased risk for respiratory arrest HDM, cat and CR sensitization are RF for emergency treatment Grass pollen sensitization (“thunderstorm asthma”) is associated with asthma exacerbation epidemics

  13. Role of Atypical Bacteria? Cunningham et al (Eur Respir J 1998) showed strong correlation between C. pneumoniae-specific IgA in NLF and asthma exacerbation frequency in children Wark et al (Eur Respir J 2002) found 38% of adults treated in ED for asthma exacerbations had serologic evidence of C. pneumoniae reactivation and greater lower airway inflammation Both studies had high viral detection rates (85% and 76%)

  14. Role of Atypical Bacteria? Johnston et al (NEJM 2006) performed RDBPCT with telithromycin in adult asthmatics experiencing acute exacerbations >50% of patients had serologic evidence of infection but only 3 by PCR assay (C. pneumoniae) Telithromycin treated patients had improved symptom scores, but not lung function compared with placebo

  15. Differential Diagnosis of Acute Asthma Bronchiolitis (and other viral PNAs) Croup Bacterial Pneumonia (typical or atypical) Foreign Body Vocal Cord Dysfunction Allergic Reaction Panic Attack Congestive Heart Failure Pertussis CF exacerbation

  16. Determining Exacerbation Severity Clinical signs and symptoms Objective measurements (functional assessment) Implications for management

  17. Signs and Symptoms of Acute Asthma Modified from NAEPP Guidelines 2007

  18. Determining Severity: PEF

  19. Determining Severity: Functional Assessment

  20. RF for Asthma-Related Death: Asthma History Previous severe exacerbations (especially history of ETI or ICU admission) ≥2 admissions for asthma within previous 12 months ≥3 ED visits for asthma within previous 12 months Hospitalization or ED visit within past month Use of >2 canisters of SABA/month Difficulty perceiving asthma symptoms or severity of exacerbations

  21. Other RF for Asthma-Related Death Social: low SES or inner city residence, illicit drug use or other major psychosocial problems Comorbidities: cardiovascular disease, other chronic lung disease, chronic psychiatric disease

  22. Special Consideration: Infants Infants high-risk group for respiratory failure Greater peripheral airway resistance Fewer collateral channels of ventilation Further extension of airway smooth muscle into the peripheral airways Less elastic recoil Mechanical disadvantage of the diaphragm Ventilation/perfusion characteristics promote hypoxemia more readily than older children/adults

  23. Special Consideration: Infants Use of accessory muscles, inspiratory/expiratory wheezing, paradoxical breathing, cyanosis and RR>60 suggest serious distress SaO2<90% also sign of serious distress; SaO2<92% after 1 hour of treatment good indicator of need for hospitalization

  24. Initial Assessment: Brief History Time of onset and any potential causes of current exacerbation Severity of symptoms, especially compared with previous exacerbations, and response to any already given treatments All current medications and time of last dose, especially of asthma medications Any prior episodes of respiratory insufficiency due to asthma Other potentially complicating illness

  25. Initial Assessment: Physical Examination Assess the severity of the exacerbation: overall patient status, including level of alertness, fluid status, and presence of cyanosis, respiratory distress, and wheezing Identify possible complications Rule out upper airway obstruction Clues to the presence of alternative reasons for dyspnea include dysphonia, inspiratory stridor, monophonic wheezing loudest over the central airway, normal values for PaO2, and unexpectedly complete resolution of airflow obstruction with intubation.

  26. Laboratory Studies: Indications CXR: obtain if complicating process suspected CBC: consider for patients with suspected serious bacterial infections ABG: indicated in patients suspected of hypoventilation, severe distress or FEV1 or PEF ≤25% predicted or personal best after initial treatment VBG: PCO2>45 mmHg may serve as a screening test but cannot substitute for an ABG Serum electrolytes generally not indicated unless patient at risk for electrolyte disturbances

  27. Treatment Goals Correction of hypoxemia Rapid reversal of airflow obstruction Reduction of likelihood of relapse or recurrence of exacerbation

  28. Assess Severity • Patients at high risk for a fatal attack require immediate medical attention after initial treatment. • Symptoms and signs suggestive of a more serious exacerbation such as marked breathlessness, inability to speak more than short phrases, use of accessory muscles, or drowsiness should result in initial treatment while immediately consulting with a clinician. • Less severe signs and symptoms can be treated initially with assessment of response to therapyand further steps as listed below. • If available, measure PEF—values of 50–79%predicted or personal best indicate the need for • quick-relief mediation. Depending on the response to treatment, contact with a clinician may also be indicated. Values below 50% indicate the need for immediate medical care. Initial Treatment • Inhaled SABA: up to two treatments 20 minutes apart of 2–6 puffsby MDI+ VHC or nebulizer treatments. Poor Response: Marked wheezing and dyspnea.PEF <50% predicted orpersonal best. • Add oral systemic corticosteroid. • Repeat inhaled SABA immediately. • If distress is severe and nonresponsive to initial treatment: —Call your doctor AND —PROCEED TO ED; —Consider calling 9–1–1 (ambulance transport). Good Response: No wheezing or dyspnea(assess tachypnea in youngchildren).PEF ≥80% predicted orpersonal best. • Contact clinician for • follow-up instructions/management • May continue inhaled SABA every 3–4 hours for 24–48 hours. • Consider short course oforal systemic corticosteroids for high-risk patients Incomplete Response: Persistent wheezing anddyspnea (tachypnea).PEF 50–79% predicted orpersonal best. • Add oral systemic corticosteroid. • Continue inhaled SABA. • Contact clinician urgently (this day) for further instruction. To ED Modified from NAEPP Guidelines 2007

  29. Initial Assessment Brief history, physical examination , PEF or FEV1, oxygen saturation, and other tests as indicated. Mild-to-Moderate (FEV1 or PEF ≥40%) • Oxygen to achieve SaO2 ≥90% • SABA up to 3 doses in first hour • Oral CS if no immediate response or recently took oral CS or high-risk patient Severe (FEV1 or PEF <40%) • Oxygen to achieve SaO2 ≥90% • SABA + ipratropium q20min or continuously for 1h;Oral CS Impending or Actual Respiratory Arrest • Intubation and mechanical ventilation (FiO2 1.0) • Nebulized SABA + ipratropium; consider adjunct therapies; Intravenous CS Admit to Hospital Intensive Care Repeat Assessment Symptoms, physical examination, PEF, O2 saturation, other tests as needed Moderate Exacerbation Physical exam: moderate symptoms; FEV1 or PEF 40–69% • Inhaled SABA q1h;Oral CS • Continue treatment 1–3 hours if improvement; make admit decision in <4 hours Severe Exacerbation Physical exam: severe symptoms at rest, accessory muscle use, chest retractions; FEV1 or PEF <40%. History: high-risk patient. No improvement after initial treatment:Oxygen, Nebulized SABA + ipratropium, hourly or continuous; consider adjunct therapies,Oral CS Good Response (FEV1 or PEF ≥70%) • Response sustained 1 hr after last SABAPhysical exam: normal; no distress Incomplete Response (FEV1 or PEF 40–69%) Mild-to-moderate symptoms Poor Response (FEV1 or PEF <40%) • PCO2 ≥42 mm Hg • Physical exam: symptoms severe, • drowsiness, confusion Individualized decision re: hospitalization Discharge Home • Continue inhaled SABA. • Continue course of oral CS. • Consider initiation of an ICS. • Patient education: − Review medications, including inhaler technique. − Review/initiate action plan. − Recommend close medical follow-up Admit to Hospital Intensive Care • Oxygen • Inhaled SABA hourly or continuously • Intravenous CS • Consider adjunct therapies • Possible intubation and mechanical ventilation Admit to Hospital Ward • Oxygen • Inhaled SABA • Systemic (oral or intravenous) CS • Consider adjunct therapies • Monitor vital signs, FEV1 or PEF, SaO2 Improve Improve Discharge Home • Continue treatment with inhaled SABAs. • Continue course of oral CS • Continue on or consider initiating ICS. • Patient education (e.g., review meds, including inhaler technique, environmental control measures; review/initiate action plan; recommend close medical follow-up. • Schedule follow-up appointment with PMD and/or asthma specialist in 1–4 weeks. Modified from NAEPP Guidelines 2007

  30. Inhaled SABA Onset of action within 5 minutes Peak effect in 30-60 minutes Duration of action 4-6 hours Promote bronchodilation by smooth muscle relaxation May be given intermittently or continuously (nebulized)

  31. Inhaled SABAs

  32. Initial Assessment Brief history, physical examination , PEF or FEV1, oxygen saturation, and other tests as indicated. Mild-to-Moderate (FEV1 or PEF ≥40%) • Oxygen to achieve SaO2 ≥90% • SABA up to 3 doses in first hour • Oral CS if no immediate response or recently took oral CS or high-risk patient Severe (FEV1 or PEF <40%) • Oxygen to achieve SaO2 ≥90% • SABA + ipratropium q20min or continuously for 1h;Oral CS Impending or Actual Respiratory Arrest • Intubation and mechanical ventilation (FiO2 1.0) • Nebulized SABA + ipratropium; consider adjunct therapies; Intravenous CS Admit to Hospital Intensive Care Repeat Assessment Symptoms, physical examination, PEF, O2 saturation, other tests as needed Moderate Exacerbation Physical exam: moderate symptoms; FEV1 or PEF 40–69% • Inhaled SABA q1h;Oral CS • Continue treatment 1–3 hours if improvement; make admit decision in <4 hours Severe Exacerbation Physical exam: severe symptoms at rest, accessory muscle use, chest retractions; FEV1 or PEF <40%. History: high-risk patient. No improvement after initial treatment:Oxygen, Nebulized SABA + ipratropium, hourly or continuous; consider adjunct therapies,Oral CS Good Response (FEV1 or PEF ≥70%) • Response sustained 1 hr after last SABAPhysical exam: normal; no distress Incomplete Response (FEV1 or PEF 40–69%) Mild-to-moderate symptoms Poor Response (FEV1 or PEF <40%) • PCO2 ≥42 mm Hg • Physical exam: symptoms severe, • drowsiness, confusion Individualized decision re: hospitalization Discharge Home • Continue inhaled SABA. • Continue course of oral CS. • Consider initiation of an ICS. • Patient education: − Review medications, including inhaler technique. − Review/initiate action plan. − Recommend close medical follow-up Admit to Hospital Intensive Care • Oxygen • Inhaled SABA hourly or continuously • Intravenous CS • Consider adjunct therapies • Possible intubation and mechanical ventilation Admit to Hospital Ward • Oxygen • Inhaled SABA • Systemic (oral or intravenous) CS • Consider adjunct therapies • Monitor vital signs, FEV1 or PEF, SaO2 Improve Improve Discharge Home • Continue treatment with inhaled SABAs. • Continue course of oral CS • Continue on or consider initiating ICS. • Patient education (e.g., review meds, including inhaler technique, environmental control measures; review/initiate action plan; recommend close medical follow-up. • Schedule follow-up appointment with PMD and/or asthma specialist in 1–4 weeks. Modified from NAEPP Guidelines 2007

  33. Inhaled Anticholinergics

  34. Systemic Corticosteroids Prednisone/Methylprednisolone/Prednisolone Children ≤ 12 yo: 1-2 mg/kg/day (max 60 mg/day) for 3-10 days until PEF is 70% predicted or personal best Children >12 yo: 40-80 mg/day for 3-10 days until PEF is 70% predicted or personal best

  35. Preschool Wheezers: The Great CS Debate Panickar et al (NEJM 2009) performed RDBPCT comparing oral prednisolone to placebo in 687 children between ages of 10 and 60 months Majority of children experienced mild-moderate wheezing Primary outcome was length of hospitalization; secondary outcomes were PRAM score, albuterol use and 7-day symptom scores

  36. Preschool Wheezers: The Great CS Debate Prednisolone no better than placebo for any outcome Study strengths: RDBPCT, large number of patients, use of standardized scoring (PRAM), majority of patients with viral wheezer phenotype Limitations: possibly under-dosing of prednisolone for a significant number of patients, lack of data on subjects refusing participation, no provision of age of patients at high-risk for persistent asthma, no viral studies

  37. Preschool Wheezers: The Great CS Debate Several other studies have found contradictory results, particularly in patients at high-risk for the development of atopic asthma (positive API) Recent study found reduced rate of relapse in subjects infected with RV when treated with prednisolone as compared to placebo Study by Ducharme et al (NEJM 2009) showed decreased exacerbation severity in subjects treated with high-dose inhaled fluticasone at the onset of a URI-induced exacerbation

  38. Systemic Corticosteroids: Summary Always indicated for patients with severe exacerbations Generally not indicated for patients with mild exacerbations unless high-risk for asthma-related death Indicated for patients with moderate exacerbations if no immediate response to SABA treatment or high-risk for asthma-related death

  39. Initial Assessment Brief history, physical examination , PEF or FEV1, oxygen saturation, and other tests as indicated. Mild-to-Moderate (FEV1 or PEF ≥40%) • Oxygen to achieve SaO2 ≥90% • SABA up to 3 doses in first hour • Oral CS if no immediate response or recently took oral CS or high-risk patient Severe (FEV1 or PEF <40%) • Oxygen to achieve SaO2 ≥90% • SABA + ipratropium q20min or continuously for 1h;Oral CS Impending or Actual Respiratory Arrest • Intubation and mechanical ventilation (FiO2 1.0) • Nebulized SABA + ipratropium; consider adjunct therapies; Intravenous CS Admit to Hospital Intensive Care Repeat Assessment Symptoms, physical examination, PEF, O2 saturation, other tests as needed Moderate Exacerbation Physical exam: moderate symptoms; FEV1 or PEF 40–69% • Inhaled SABA q1h;Oral CS • Continue treatment 1–3 hours if improvement; make admit decision in <4 hours Severe Exacerbation Physical exam: severe symptoms at rest, accessory muscle use, chest retractions; FEV1 or PEF <40%. History: high-risk patient. No improvement after initial treatment:Oxygen, Nebulized SABA + ipratropium, hourly or continuous; consider adjunct therapies,Oral CS Good Response (FEV1 or PEF ≥70%) • Response sustained 1 hr after last SABAPhysical exam: normal; no distress Incomplete Response (FEV1 or PEF 40–69%) Mild-to-moderate symptoms Poor Response (FEV1 or PEF <40%) • PCO2 ≥42 mm Hg • Physical exam: symptoms severe, • drowsiness, confusion Individualized decision re: hospitalization Discharge Home • Continue inhaled SABA. • Continue course of oral CS. • Consider initiation of an ICS. • Patient education: − Review medications, including inhaler technique. − Review/initiate action plan. − Recommend close medical follow-up Admit to Hospital Intensive Care • Oxygen • Inhaled SABA hourly or continuously • Intravenous CS • Consider adjunct therapies • Possible intubation and mechanical ventilation Admit to Hospital Ward • Oxygen • Inhaled SABA • Systemic (oral or intravenous) CS • Consider adjunct therapies • Monitor vital signs, FEV1 or PEF, SaO2 Improve Improve Discharge Home • Continue treatment with inhaled SABAs. • Continue course of oral CS • Continue on or consider initiating ICS. • Patient education (e.g., review meds, including inhaler technique, environmental control measures; review/initiate action plan; recommend close medical follow-up. • Schedule follow-up appointment with PMD and/or asthma specialist in 1–4 weeks. Modified from NAEPP Guidelines 2007

  40. Magnesium Sulfate (IV) Meta-analyses (adult and peds studies) show that hospitalization rates decreased when MgSO4 added to conventional Rx for severe exacerbations Dose 25-75 mg/kg up to 2 g NAEPP recommendation: “consider in patients with life-threatening exacerbations and patients who remain in the severe category after 1 hour of intensive conventional therapy”

  41. Heliox Theoretical benefit for improving gas exchange because of helium’s low density Studies contradictory Three studies (1 peds, 2 adult) showed improvement in subjects experiencing moderate-severe exacerbations treated with Heliox-driven SABA treatments when compared to subjects receiving O2-driven SABA treatments

  42. Leukotriene Receptor Antagonists RT showed significant improvement in pulmonary function within 10 minutes of administration of IV montelukast to patients with moderate-severe exacerbations Oral montelukast does not take effect before 90 minutes from time of administration

  43. Systemic β2 Agonists

  44. When to Intubate Signs of impending respiratory failure: Inability to speak Altered mental status Worsening fatigue Significant and prolonged retractions PCO2 ≥ 42 mm Hg Theoretical benefit of ketamine as a premedication for ETI has not born out in studies (limited data)

  45. Assessing Response to Treatment Serial physical examinations Serial FEV1 or PEF Serial pulse oximetry measurements Signs and symptom scores

  46. Predicting Need for Hospitalization Kelly et al (Respir Med 2004) showed that severity assessment at 1hour after initial treatment with SABA was better predictor of need for hospitalization than initial assessment After 1hour if meets criteria for severe exacerbation >86% chance of hospitalization; if moderate after 1 hour >84% chance of hospitalization; if mild then only 18% chance of hospitalization SaO2 <92-94% at 1 hour better predictor of need to hospitalize than initial SaO2

  47. Initial Assessment Brief history, physical examination , PEF or FEV1, oxygen saturation, and other tests as indicated. Mild-to-Moderate (FEV1 or PEF ≥40%) • Oxygen to achieve SaO2 ≥90% • SABA up to 3 doses in first hour • Oral CS if no immediate response or recently took oral CS or high-risk patient Severe (FEV1 or PEF <40%) • Oxygen to achieve SaO2 ≥90% • SABA + ipratropium q20min or continuously for 1h;Oral CS Impending or Actual Respiratory Arrest • Intubation and mechanical ventilation (FiO2 1.0) • Nebulized SABA + ipratropium; consider adjunct therapies; Intravenous CS Admit to Hospital Intensive Care Repeat Assessment Symptoms, physical examination, PEF, O2 saturation, other tests as needed Moderate Exacerbation Physical exam: moderate symptoms; FEV1 or PEF 40–69% • Inhaled SABA q1h;Oral CS • Continue treatment 1–3 hours if improvement; make admit decision in <4 hours Severe Exacerbation Physical exam: severe symptoms at rest, accessory muscle use, chest retractions; FEV1 or PEF <40%. History: high-risk patient. No improvement after initial treatment:Oxygen, Nebulized SABA + ipratropium, hourly or continuous; consider adjunct therapies,Oral CS Good Response (FEV1 or PEF ≥70%) • Response sustained 1 hr after last SABAPhysical exam: normal; no distress Incomplete Response (FEV1 or PEF 40–69%) Mild-to-moderate symptoms Poor Response (FEV1 or PEF <40%) • PCO2 ≥42 mm Hg • Physical exam: symptoms severe, • drowsiness, confusion Individualized decision re: hospitalization Discharge Home • Continue inhaled SABA. • Continue course of oral CS. • Consider initiation of an ICS. • Patient education: − Review medications, including inhaler technique. − Review/initiate action plan. − Recommend close medical follow-up Admit to Hospital Intensive Care • Oxygen • Inhaled SABA hourly or continuously • Intravenous CS • Consider adjunct therapies • Possible intubation and mechanical ventilation Admit to Hospital Ward • Oxygen • Inhaled SABA • Systemic (oral or intravenous) CS • Consider adjunct therapies • Monitor vital signs, FEV1 or PEF, SaO2 Improve Improve Discharge Home • Continue treatment with inhaled SABAs. • Continue course of oral CS • Continue on or consider initiating ICS. • Patient education (e.g., review meds, including inhaler technique, environmental control measures; review/initiate action plan; recommend close medical follow-up. • Schedule follow-up appointment with PMD and/or asthma specialist in 1–4 weeks. Modified from NAEPP Guidelines 2007

  48. Plan for Discharge Provide patients written instructions regarding dose, frequency and correct use of medications Consider initiating or continue with ICS Schedule follow-up appointment with PMD or asthma specialist within 4 weeks

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