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Acute Asthma

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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.

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