Update on Update on

Acute AsthmaAcute Asthma

Carlos Camargo, MD, DrPH

Emergency Medicine, MGH

Channing Laboratory, BWH

Harvard Medical School

www.emnet-usa.org

Outline of Presentation

• Background

• NAEPP guidelines

• Novel therapies

• Preventive interventions

• Summary

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

NAEPP Guidelines, 1997• National Asthma Education and Prevention Program (NAEPP)

• Classification of chronic asthma:

–Mild intermittent asthma

–Mild persistent asthma (>2 days/wk, >2 nights/mo)

–Moderate persistent asthma

–Severe persistent asthma

• Inhaled corticosteroids (ICS) are “preferred treatment” for all patients with persistent asthma

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 )

Asthma Prevalence, 1980-2001

* 11.3

* 4.3

* 7.3

NHIS 2001

Asthma Prevalence, 1980-2001

* 11.3

* 4.3

* 7.3

NHIS 2001

Asthma Mortality, 1980-1999

Asthma Mortality Rates Per 1,000,000By Year -- USA

0

5

10

15

20

25

1980 1985 1990 1995 1999

Year

Rat

e p

er

1,00

0,00

0

ED Visits for Asthma, 1992-2000V

isits

in th

ou

san

ds

NHAMCS Database

1000

1200

1400

1600

1800

2000

2200

2400

1992-93 1994-95 1996-97 1998-99 2000

Year (s)

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

EMNet Sites (137 US sites)

9/22/04

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

ED Patients with Acute Asthma

1996 (n=770)

1997-98 (n=4,920)

1999-01 (n=1,248)

Ever admitted for asthma (%) 54 63 64

Ever intubated (%) 15 17 17

ED visits in past year (%) 76 90 79

Used inhaled corticosteroids in past 4 weeks (%)

42

44

46

ED and Hospital Management: ED and Hospital Management: GoalsGoals

1. Correct significant hypoxemia

2. Rapidly reverse airflow obstruction

3. Decrease likelihood of recurrence

NAEPP, 1997

ED and Hospital Management: ED and Hospital Management: Initial TreatmentInitial Treatment

Mild-to-Moderate Exacerbation (PEF Mild-to-Moderate Exacerbation (PEF >> 50%) 50%)

• Oxygen to achieve O2 sat > 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

ED Treatment, 1992-1999

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

1993 1994 1995 1996 1997 1998 1999

AntiasthmaticCorticosteroidAntimicrobial

% U

s age

National Center for Health Statistics, CDC

ED Treatment, 1992-1999

Systemic Steroids at Discharge

FF

F

1996 1997-1998 1999-20010

10

20

30

40

50

60

70

80

90

100

P for trend <0.001

ED and Hospital Management:ED and Hospital Management:Initial Treatment Initial Treatment (continued)(continued)

Severe Exacerbation (PEF < 50%)Severe Exacerbation (PEF < 50%)

• Oxygen to achieve O2 sat > 90%

• Inhaled high-dose 2 -agonist and

anticholinergic by neb q 20 minutes or continuously for 1 hour

• Oral corticosteroid

NAEPP, 1997

ED and Hospital Management:ED and Hospital Management:Initial Treatment Initial Treatment (continued)(continued)

Impending or Actual Respiratory ArrestImpending or Actual Respiratory Arrest

• Intubation and Intubation and mech ventilationmech ventilation with 100% O with 100% O2 2

• Nebulized Nebulized 2-agonist-agonist and and anticholinergicanticholinergic

• IV corticosteroidIV corticosteroid

• Admit to hospital intensive careAdmit to hospital intensive care

NAEPP, 1997

2002 Update on Selected Topics2002 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

Dual Therapy with ICS + LABA (weeks)

Dual Therapy with ICS + LABA (days)

Novel Therapies in the ED

• IV magnesium

• Heliox

• IV leukotriene modifiers

www.emnet-usa.org

IV Mg for Acute Asthma – Admit Rate

Heliox for Severe Acute Asthma – PEF

IV Montelukast for Acute Asthma – FEV1

0

5

10

15

20

25

30

0 10 20 30 40 50 60

Minutes after treatment dose

LSM

ean

% C

hang

e fr

om b

asel

ine

(+-S

E)

Montelukast IV 7 mg

Montelukast IV 14 mg

Placebo

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:

1. ICS initiation at discharge from ED

2. Asthma education programs

3. Bridging the gap between ED & primary asthma care

Initiation of ICS at Discharge

F F

1996 1997-1998 1999-20010

10

20

30

40

50

60

70

80

90

100

*

ICS after the ED -- Relapse at 20-24 Days

Prevention of Repeat ED Visits

Prevention of Fatal Asthma2.0

1.5

1.0

0.5

0.0

0 2 4 6 8 10 12

MDIs of Inhaled Corticosteroids per Year

Rat

e R

atio

of

Ast

hm

a D

eath

1

Suissa & Ernst, JACI 2001.

Mission StatementMission 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.

National Asthma Educator Certification Board

www.naecb.org

Follow-up with PCP

• Philadelphia study

– randomized trial, 1 center, n=178

– $25 intervention (free meds, taxi vouchers, 48-hr call)

– f/u with PCP: usual care (29%) vs. intervention (46%), p=0.02

RR=1.6 (95%CI, 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

Follow-up with PCP• Philadelphia study

– randomized trial, 1 center, n=178

– $25 intervention (free meds, taxi vouchers, 48-hr call)

– f/u with PCP: usual care (29%) vs. intervention (46%), p=0.02

RR=1.6 (95%CI, 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?

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