Update on Acute Asthma

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Update on Acute Asthma

• Carlos Camargo, MD, DrPH
• Emergency Medicine, MGH
• Channing Laboratory, BWH
• Harvard Medical School

www.emnet-usa.org
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Outline of Presentation

• Background
• NAEPP guidelines
• Novel therapies
• Preventive interventions
• Summary

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Definition of Asthma

• Chronic lung disease characterized by
• Airway narrowing that is reversible (
  completely) either spontaneously or with
  treatment
• Airway inflammation
• Airway hyper-responsiveness to a variety of
  stimuli.
• Episodic dyspnea with associated wheezing
• Heterogeneous group with
• Shortness of breath
• Wheezing
• Cough

ATS. ARRD 1987
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NAEPP Guidelines, 1997

• National Asthma Education and Prevention Program
  (NAEPP)
• Classification of chronic asthma
• Mild intermittent asthma
• Mild persistent asthma (gt2 days/wk,
  gt2 nights/mo)
• Moderate persistent asthma
• Severe persistent asthma
• Inhaled corticosteroids (ICS) are preferred
  treatment for all patients with persistent asthma

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Epidemiology

• 17 - 27 million Americans (6-10 prevalence)
• 10 million office visits 2 million ED visits
  
• 500,000 hospitalizations 5,000 deaths
• Major cause of school and work absences
• At least 12 billion per year
• Increasing burden for years ... but now flat (or
  ? )

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Asthma Prevalence, 1980-2001
NHIS 2001
11.3
7.3
4.3
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Asthma Prevalence, 1980-2001
NHIS 2001
11.3
7.3
4.3
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Asthma Mortality, 1980-1999
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ED Visits for Asthma, 1992-2000
Visits in thousands
NHAMCS Database
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MARC

• Founded 1996
• Goal To improve care of acute asthma other
  airway disorders
• Funded by NIH, industry, foundations
• Emergency Medicine Network
• www.emnet-usa.org

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EMNet Sites (137 US sites)
9/22/04
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Potential for Improving Asthma

• ED is often used for asthma care
• 2 million ED visits per year
• Most asthma hospitalizations begin in the ED
• Among ED patients (MARC data)
• 74 adults (63 children) use ED for all
  problem asthma care
• 45 adults (31 children) receive all asthma Rx
  from ED
• With PCP 63 61 for problem care 24 25
  for all Rx
• High-risk population

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ED Patients with Acute Asthma
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ED and Hospital Management Goals

• Correct significant hypoxemia
• Rapidly reverse airflow obstruction
• Decrease likelihood of recurrence

NAEPP, 1997
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ED and Hospital Management Initial Treatment

• Mild-to-Moderate Exacerbation (PEF gt 50)
• Oxygen to achieve O2 sat gt 90
• Inhaled ? 2-agonist by MDI or neb, up to 3 in 1st
  hr
• Oral corticosteroid if no immediate response or
  if patient recently took oral corticosteroid

NAEPP, 1997
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ED Treatment, 1992-1999
ED Treatment, 1992-1999
90
80
70
Antiasthmatic
Corticosteroid
60
Antimicrobial
Usage
50
40
30
20
10
0
1993
1994
1995
1996
1997
1998
1999
National Center for Health Statistics, CDC
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Systemic Steroids at Discharge
P for trend lt0.001
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ED and Hospital ManagementInitial Treatment
(continued)

• Severe Exacerbation (PEF lt 50)
• Oxygen to achieve O2 sat gt 90
• Inhaled high-dose ?2 -agonist and anticholinergic
  by neb q 20 minutes or continuously for 1 hour
• Oral corticosteroid

NAEPP, 1997
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ED and Hospital ManagementInitial Treatment
(continued)

• Impending or Actual Respiratory Arrest
• Intubation and mech ventilation with 100 O2
• Nebulized ?2-agonist and anticholinergic
• IV corticosteroid
• Admit to hospital intensive care

NAEPP, 1997
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2002 Update on Selected Topics

• Antibiotics not recommended for acute asthma
• ICS are preferred treatment for children of all
  ages with persistent asthma
• ICS long-acting ?-agonist is the preferred
  treatment for moderate or severe persistent
  asthma in individuals age 6 and older

NAEPP, 2002
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Dual Therapy with ICS LABA (weeks)
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Dual Therapy with ICS LABA (days)
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Novel Therapies in the ED

• IV magnesium
• Heliox
• IV leukotriene modifiers

www.emnet-usa.org
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IV Mg for Acute Asthma Admit Rate
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Heliox for Severe Acute Asthma PEF
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IV Montelukast for Acute Asthma FEV1
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ED-Initiated Preventive Interventions

• High-risk population
• Use of ED for problem asthma care asthma Rx
• What interventions are feasible in the ED
  setting?
• Examples from MARC
• ICS initiation at discharge from ED
• Asthma education programs
• Bridging the gap between ED primary asthma care

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Initiation of ICS at Discharge

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ICS after the ED -- Relapse at 20-24 Days
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Prevention of Repeat ED Visits
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Prevention of Fatal Asthma
Suissa Ernst, JACI 2001.
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National Asthma Educator Certification Board

• Mission Statement
• To promote optimal asthma management and
• quality of life among individuals with asthma,
• their families and communities, by advancing
• excellence in asthma education through the
• Certified Asthma Educator process.

www.naecb.org
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Follow-up with PCP

• Philadelphia study
• randomized trial, 1 center, n178
• 25 intervention (free meds, taxi vouchers, 48-hr
  call)
• f/u with PCP usual care (29) vs. intervention
  (46), p0.02
• RR1.6 (95CI, 1.1-2.4)
• EMF Center of Excellence Award
• Recently completed RCT at 9 EMNet sites
• 1 month 50 increase in PCP follow-up (ACEP
  2001)

Baren et al, Ann Emerg Med 2001
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Follow-up with PCP

• Philadelphia study
• randomized trial, 1 center, n178
• 25 intervention (free meds, taxi vouchers, 48-hr
  call)
• f/u with PCP usual care (29) vs. intervention
  (46), p0.02
• RR1.6 (95CI, 1.1-2.4)
• EMF Center of Excellence Award
• Recently completed RCT at 9 EMNet sites
• 1 month 50 increase in PCP follow-up (ACEP
  2001)
• 6 and 12 months no diff in clinical outcomes
  (ACEP 2002)
• Next steps facilitated referral to
  specialists?

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Summary

• Asthma epidemiology
• NAEPP guidelines
• 1997 O2 prn, inhaled ß-agonist antichol,
  systemic steroids
• 2002 ICS for children of all ages with
  persistent asthma
• ICS LABA for age 6 with moderate-severe
  persistent
• Novel treatments severe exacerbations only
• Prevention at all clinical encounters!
• Start ICS at ED discharge consider ICS LABA
• Asthma education (brief) consider outpatient
  session
• Arrange continuing care consider referral to
  specialist