Acute Asthma

Katy Horan, MD
February 27, 2010

Overview
• Definition of asthma
• Initial assessment of acute asthma
• Treatment
Pharmacologic
Ventilation
Will not cover chronic, outpatient therapy
• Special populations
• Asthma imitators

What is asthma
• Chronic lung condition with episodes of
wheezing, chest tightness, cough, and
dyspnea
• Severity defined by
Frequency of daytime symptoms
Frequency of nighttime symptoms
• Triggers
• Disease can be controlled

What is asthma
• Reversible airflow obstruction
Bronchoconstriction
Excess mucous production and inflammation
Source: “What You and Your Family Can Do About Asthma” by the Global Initiative For Asthma
Created and funded by NIH/NHLBI, 1995

Kunzli, et al. Am J Resp Crit Care Med.174; 2006:1221-1228

Asthma Triggers
• Irritants
Air quality
Smoking
• EMS professionals 17% smokers
• Allergens (pet dander, dust mites, pollens)
• Exercise
• Change in weather
Rainstorms (disrupting/dispersing pollen)
Cold air
• Infections (viral, sinusitis, ear infections)
• Occupations (isocyanates, latex, wood dust)
Studnek, et al. Prehospital Emerg Care. 14:1; 2010 (14-20)
D’Amato, et al. Allergy 62:1; 2007 (11-16))

Asthma Prevalence by Sex
United States, 1980-2007
Prevalence (%)
14
12
10
• Female
• Male
8
12-Month
6
4
Lifetime
Current
2
0
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
Year
Source: National Health Interview Survey; CDC National Center for Health Statistics

Asthma Prevalence by Race/Ethnicity
United States, 1997-2007
Prevalence (%)
18
16
14
12
10
8
6
4
2
0
Lifetime
1997
1998
Current
1999
2000
2001
2002
2003
Source: National Health Interview Survey; National Center for Health Statistics
2004
2005
2006
2007
Year
▲ Black NH
• White NH
• Hispanic

Asthma Mortality Rates by Age
United States: 1979-2005
Rate per million
100
80
60
40
20
0
65 +
ICD-9
35-64
5-9
1980
1982
1984
1986
1988
1990
1992
1994
Source: Underlying Cause of Death; CDC National Center for Health Statistics
* Age-adjusted to 2000 U.S. population
1996
1998
2000
2002
2004
ICD-10
Year

Asthma Mortality Rates by Race
United States: 1979-2005
Rate per million
60
50
40
30
20
10
0
ICD-9
Black
Other
White
1980
1982
1984
1986
1988
1990
1992
Source: Underlying Cause of Death; CDC National Center for Health Statistics
* Age-adjusted to 2000 U.S. population
1994
1996
1998
2000
2002
2004
ICD-10
Year

Akinbami, et al. CDC. Gov 2007
Fatal Asthma
• Demographically lower, non‐white , urban
44/million Puerto Rican Hispanics
33/million non Hispanic blacks
11/million non‐Hispanic whites

Risk Factor for Fatal Asthma
• Asthma history
Prior intubation (OR 28)
Prior ICU admit (OR10)
>2 hospitalization/y
>3 ED visits/y
Any hosp/ED/last month
>2 canisters of SABA
Poor symptom
perception
No action plan
• Social history
Low socioeconomic
status
Illicit drug use
Psychosocial issues
• Comorbities
Heart disease
Lung disease
Psychiatric issues
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma
Turner et al. Am J Respir Crit Care Med 1998; 157:1804

Managing Asthma:
Sample Asthma Action Plan
Describes medicines
to use and actions to
take
National Heart, Blood, and Lung Institute Expert Panel Report 3 (EPR 3): Guidelines for the
Diagnosis and Management of Asthma. NIH Publication no. 08-4051, 2007.

Risk Factor for Fatal Asthma
• Asthma history
Prior intubation (OR 28)
Prior ICU admit (OR10)
>2 hospitalization/y
>3 ED visits/y
Any hosp/ED/last month
>2 cntr of SABA/mth
Poor symptom
perception
No action plan
• Social history
Low socioeconomic
status
Illicit drug use
Psychosocial issues
• Comorbities
Heart disease
Lung disease
Psychiatric issues
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma
Turner et al. Am J Respir Crit Care Med 1998; 157:1804

Minor Risk Factors for
Acute Asthma
• Allergies
• Aspirin and NSAIDs
• Exercise (running)
• Cocaine and heroin use
• Tobacco smoke exposure
• Menstruation
• Respiratory viruses
• Low FEV1
• Poor dyspnea perception

Initial assessment of acute
asthma
• History
• Vitals
• Exam
• Peak expiratory
flow
Also known as
“peak flow” or peak
expiratory flow rate
PEFR

Peak Expiratory Flow
• Measures velocity of exhalation which can be
slowed in asthma
• Best measured on a consistent basis in order to
draw comparisons
>20% decline in PEF abnormal
>50% decline indicates a severe exacerbation
• Should be used in conjunction with symptom
monitoring and clinical assessment
• Limited value (only age >5 can complete)
• In severe, acute asthma, only 65% able to
complete the manuever.

Classifying Severity of AE
Symptoms/Signs Initial PEF Clinical Course
MILD Dyspnea with activity PEF>70% Home care; relief with SABA;
may need short course oral
CS
MODERATE
Dyspnea interferes
with usual activity
PEF 40‐
69%
Office or ED visit; relief with
frequent SABA use; oral CS
with sx 1‐2d after CS start
SEVERE
Near fatal
Dyspnea at rest,
interferes with
speech
Too dyspneic to
speak
PEF

Adapted from British Guidelines on Management of Asthma. 2009
Initial assessment of acute
• asthma ACUTE SEVERE
SpO2 110 adult
• >125 (>5y)
• >140 (2‐5y)
RR
• >25breath/min adult
• >30breaths/min (>5y)
• >40 breaths/min (2‐5y)
• LIFE THREATENING
• SpO2

Infants with severe asthma
• Assessment relies on physical exam
Use of accessory muscles
Inspiratory and expiratory wheezing
Cyanosis
RR>60
• Lack of response to SABA indicates need for
hospitalization
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma

Acute management of asthma
• “Early treatment best”
• action plan
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma

CASE #1 At Home
• 56 yo with PMH asthma presents with a 3
week history of increasing cough, wheeze,
and nocturnal use of her short acting beta
agonist
• Patient smokes 1/2ppd, but hasn’t been able
to for 2weeks.
• Husband smokes in the home
• Admitted to ICU 5 years ago with asthma

QuickTime and a
decompressor
are needed to see this picture.

Case #1 Exam
• O2 sat 93% on room air
• HR 128, sinus
• RR 26
• Speaking in 3 word sentences
• Sitting up, cannot lie down
• Insp/exp wheezes
How would you classify the severity

Adapted from British Guidelines on Management of Asthma. 2009
Initial assessment of acute
• asthma ACUTE SEVERE
SpO2 110 adult
• >125 (>5y)
• >140 (2‐5y)
RR
• >25breath/min adult
• >30breaths/min (>5y)
• >40 breaths/min (2‐5y)
• LIFE THREATENING
• SpO2

What are her risks for
severe asthma

Risk Factor for Fatal Asthma
• Asthma history
Prior intubation (OR 28)
Prior ICU admit (OR10)
>2 hospitalization/y
>3 ED visits/y
Any hosp/ED/last month
>2 cntr of SABA/mth
Poor symptom
perception
No action plan
• Social history
Low socioeconomic
status
Tobacco use
Psychosocial issues
• Comorbities
Heart disease
Lung disease
Psychiatric issues
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma
Turner et al. Am J Respir Crit Care Med 1998; 157:1804

Prehospital management of
acute asthma
• Supplemental oxygen as needed
• SABA via nebulizer or MDI with spacer
Do not delay transport in order initiate SABA
Repeat q 20min SABA up to 3x in the first hour;
1x/hour thereafter
Reassess vitals and breath sounds after each
• Protocols may allow for ipratropium
• Able to recognize need for mechanical
ventilation
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma

Prehospital management
• Systemic corticosteroids
Prehospital CS
Retrospective, ARR 20.4% of hospital admission,
decreased time to CS (15min CI 2‐22 vs. 40min CI
23‐57)
Knapp and Wood. Prehosp Emerg Care 2003; 7; (423-6)

Case #1
•SABAs
QuickTime and a
decompressor
are needed to see this picture.
•Ipratropium
•IV corticosteroids
•Adjunct therapies
•Decision to admit

QuickTime and a
decompressor
are needed to see this picture.

QuickTime and a
decompressor
are needed to see this picture.

Nebulizer vs. MDI
• Nebulizer inefficient (large particle
size, loss of medications through
exhalation port)
• Less total dose of drug with MDI
• Same clinical effectiveness
• 4-6puffs with spacer=1 nebulized
dose
• Continuous vs. intermittent in ED
Continuous may be better in severe
asthma without change in HR, K, or
tremor
Camargo CA, et al. Cochrane Database of Systemic Reviews. 2003

Adjunct Therapies for Acute
Asthma
• Magnesium
• Heliox
• Leukotriene Receptor Antagonists

Magnesium
• Role in bronchodilation and decreased inflammation
• Magnesium 2g IV over 20min
7 trials, n=665 (5 adult, 2 peds)
No sign change in PEFR, except in severe
No change in admission, except in severe (OR=.10)
Safe (avoid in renal failure, avoid overdose)
• Nebulized magnesium with SABA
In subset with severe asthma, significant improvement in
lung function
Trend to less hospitalization
Rowe BH, et al. Cochrane Database of Systematic Reviews 2000
Blitz M, et al. Cochrane Database of Systematic Reviews 2005c

Heliox in asthma
• Mixture of helium and oxygen
• Less turbulent flow due to low density gas
• No difference pulmonary function or
admission rates for adults or peds in all ED
visits for asthma
• May play a role in severe, nonintubated
asthma, but the data is not robust.
Rodrigo GJ, et al. Cochrane Database of Systematic Reviews 2006

Leukotriene Receptor
Antagonists
• Used as controller therapies
• Small studies suggest that IV or PO LTRAs
can improve lung function, decrease time in
ED, and decrease treatment failure.
Camargo CA, Jr , et al. Am J Resp Crit Care Med. 2003. 167(4) 528-33
Silverman RA, et al. Chest. 2004. 126(5) 1480-9

Adjuncts that are not
recommended
• IV theophylline or aminophylline
• ICS once hospitalized for acute asthma
• IV fluids for adults
• Chest physiotherapy
• Mucolytics
• Sedation
• Antibiotics
Adapted from NHBLI EPR-3, www.nhlbi.nih.gov/guidelines/asthma

Ventilation in near fatal
asthma
• Mechanical ventilation
• Noninvasive ventilation

Case #1: in the ICU
• Improved somewhat in the ED
• Rec’d iv solumedrol, q20min albuterol
nebulizer therapy, magnesium
• But, acutely more dyspneic when moving
from gurney to bed in the ICU
EXAM: 94% on NRB, accessory muscle use,
agitated, can’t speak in full sentences. “tight”
minimal breath sounds, diaphoretic

Indications for ventilatory
support
• Decreased mental status
• Slowing of respiratory rate
• Hypoxemia (

Principles of ventilatory
management of asthma
• Minimize high airway pressures
Lower respiratory rates (more time to exhale)
Smaller tidal volumes (less to exhale)
• Maintain adequate oxygenation
• Permissive hypercapnia
Do not need to normalize pH, or pCO2

Complications of MV in
asthma
• Subcut air picture

Complications of MV in
asthma
• Pntx picture

Complications of MV in
asthma
• NM weakness

Complications of MV in
asthma
• Pressure limited ventilation (peak pressure
limits on ventilator.
• Barotrauma
Pneumothorax, pneumomediastinum,
subcutaneous air
• Shock, hypotension due to autopeep
• Neuromuscular weakness (critical illness
polymyoneuropathy)
Steroids and NMBAs
• Usual ICU complications

Role for NIV in asthma
• Use in COPD and CHF well established
• In asthma, could
Decrease work of breathing
EPAP offsets intrinsic PEEP
Improves tidal volume
Improve delivery of bronchodilators
Improve alveolar recruitment.
• Small, ED, n=30, BIPAP severe asthma
Improved FEV1, hospitalization rate
Soroksky, et al. Chest. 2003. 123 (4) 1018-1025

Asthma in pregnancy
• Rule of thirds
• Healthy mother=healthy baby
Smoking cessation benefits mother and child
Continue controller therapies (gestation & labor)
• Most acute exacerbations occur in 2nd trimester
• May be due to cessation of controller meds
Use inhaled SABA for symptoms
• Acute severe asthma (SABA, steroids,
magnesium, (O2 sats=94‐98%)
• Consider continuous fetal monitoring for acute
severe asthma
• Stress dose steroids for mothers on chronic oral
steroids

All that wheezes is not
asthma…

Gorur, et al. presented as abstract ERJ. 2006

Gorur, et al. presented as abstract ERJ. 2006

Asthma imitators
• CHF “cardiac wheeze”
• Epiglottitis
• Upper airway obstruction
Head and neck cancer
Trauma
• Anaphylaxis
• Vocal cord dysfunction

Summary
• Acute, severe asthma requires systematic
assessment, reassesment and treatment
• Mechanical ventilation of acute, severe
asthma is tricky
• Not all that wheezes is asthma.