Transcript Asthma Exacerbations

Asthma Exacerbations
Gil C. Grimes, MD
2008-4-17
Family Medicine
Objectives
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Discuss triggers
Describe generalized approach to
asthma exacerbation
Understand initial medical approach
Understand the role of steroids
Understand the role of supplemental
medications
Asthma Triggers
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Allergens
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Dust, dander, molds, grass pollens, tree
pollen
Synergy with respiratory viruses
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26 % of those admitted had respiratory virus
66% sensitized to mite or animal dander
BMJ 2002:30;324:763
Asthma Triggers
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Air pollutants
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Ozone, sulfur dioxide, cigarette smoke
Cohort study asthmatic children showed
association between exacerbation and
nitrogen dioxide (lancet 2003 7;36:1939)
Ozone exposure increase rescue med use
in moderate pediatric asthmatics (JAMA
2003 290;14:1859)
Asthma Triggers
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Respiratory infections
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#1 cause in young children
Seasonal viral infection can increase IgE and
eosinophils (Arch Int Med 1998 158;22:2453)
Rhinovirus increases LRT complications in
asthmatics (Lancet 2002 Mar9;359:831)
RSV bronchiolitis in child <12 months risk factor
for later asthma
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11 of 47 at 3 years with RSV
1 of 93 at 3 years without RSV
Pediatrics 1995 April;95(4):500
Consider atypical bacteria (10% of admitted peds)
Asthma Triggers
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Miscellaneous
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GERD
Perfume
Sulfites
Exercise
Emotion (laughing or crying)
Foods (shellfish, chocolate, nuts)
The case
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38 year old female with asthma who has
been wheezing since being at a party earlier
that evening. Thought she was having an
allergic reaction and gave herself Epinephrine
which helped for a while. She has been
treating with her MDI for the last two hours
without improvement (16 or more puffs).
PMH: Asthma, allergies prior tobacco
Meds: Azmacort, Singulair, Zyrtec, Albuterol
O: 134/58 P104, AF, R28 Sat 90% (RA)
Approach to the patient
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What do you do first?
What is you first medication?
How long will you do this prior to
changing?
How will you monitor for change?
Initial approach
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Precipitating Factors
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Chest pain
Sputum production
Fever
Just like prior attacks?
Have you taken steroids?
What has worked in the past?
Have you ever been intubated?
What are your medications?
Evaluation
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Physical Severe
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Tachycardia
Tachypnea
Accessory muscle use
Retractions
Flaring in infants
Ability feed in infants
Inability to recline
PEFR <50% of best
Evaluation
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Physical Life Threatening
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Cyanosis
Silent chest
Fatigue
Inability to speak
Decreased level of consciousness
PEFR <33% of best
Vitals
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Pulse oximetry
Radiograph
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Pneumothorax
Pneumomediastinum
Pneumonia
Poor response to therapy
Laboratory Testing
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ABG
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Not terribly predictive
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Stage I respiratory alkalosis decreased PCO2
Stage II alkalosis and hypoxia
Stage III fatigue CO2 rises (repeat if PCO2
>30)
Stage IV respiratory failure elevated PCO2
correlates with PEFR <200L/min
Mortality risks
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Higher in adults
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Status most common cause of death
asthmatics
Decreased FEV1, advanced age, h/o
tobacco use
Eosinophilia increases mortality 7.4x
Increased FEV1>50% after bronchodilator
increases mortality risk 7x
Clinical Calculators
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Pediatric Calculator
Asthma Score (0-10 points)
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Respiratory rate 40-60 (1 pts) >60 (2 pts)
Wheezing via stethoscope expiratory (1pt)
inspiratory & expiratory (2pts)
Retractions subcostal (1pts) subcostal &
intercostal (2pts)
Observed dyspnea mild (1pts) marked (2pts)
I-E ratio equal (1pts) I<E (2pts)
Higher score correlates with length of stay
Therapy
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Generally accepted and effective
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Oxygen supplementation (titrate)
Beta-2 agonists
Atrovent
Magnesium Sulfate (?)
Hydration
Oxygen
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First line therapy
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2-3 Liters via nasal cannula
Target 92% pulse ox
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NRB vs. Nasal cannula
100% increased PaCO2
100% decreased PEFR
Chest 2003 Oct;124(4):1312
Aerosol Medications
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Metered Dose Inhalers
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Meta-analysis of MDI vs. Neb in pediatrics
Nebs increased admission rate
Difference greatest with severe cases
Key is proper use of MDI
J Pediatric 2004 Aug 145(2):172
Beta 2 Agonist
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Demonstrated Benefit
If nebulized dose used, oxygen powered not
air powered (BMJ 2001 323:98)
Continuous Nebs more effective than once
hourly
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Every 15 minutes or continuous
No difference in side effects
Reduced admissions
Most improvement among severest group
Cochrane review Issue 2, 2004
Beta 2 agonist
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IV Route?
Cochrane review Issue 2 2004
15 studies indicates no evidence to
support this approach
Does not address SQ epinephrine or
terbutaline
Inhalation route is preferred route
Anticholinergics
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Moderate to severe exacerbations in children
Multiple doses of Anicholinergics effective
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25% reduction in admissions
NNT 12
Single dose not effective
Cochrane review Issue 2 2004
No benefit to continuing once admitted
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Arch Pediatric Adolescent Med 2001;155:1329
Steroids
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Low dose steroids appear as effective as high dose
80 mg/day of methyprednisalone
400 mg/day hydrocortisone
Parenteral no better than oral
Reduces readmission rates, relapse rate, and
rescue inhaler use for 21 days
Best if given within one hour of arrival in ED
Cochrane review Issue 2, 2004
Magnesium
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Intravenous route
Adults
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beneficial with severe exacerbation (FEV1<25% predicted)
1.2-2 gm IV over20-30 minutes
NNT 8
Ann Emerg Med 2000;36:181-90
Cochrane review Issue 2, 2004
Pediatrics
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Small RCT (30 patients)
Used 40 mg/kg IV vs. saline
NNT to prevent one admission 2
Arch Pediatric Adolescent Med 2000;154:979
Magnesium
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Nebulized route
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Small RCT 58 adults
2.5 ml mag sulfate with 2.5 mg Albuterol
via neb
3 doses q 30 minutes
NNT 5 for admission
Lancet 2003 Sept 27;362:1079
Unclear or Useless Tx
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Antibiotics
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Heliox
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No identified role
Cochrane issue 2, 2004
No identified role
Cochrane issue 2, 2004
Aminophylline
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Results in more side effects no reduction in patient
oriented outcomes
Cochrane issue 2, 2004
Decision Tree in ER
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Good response to therapy
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Admit if response is poor
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Absence of symptoms
Absence of signs
PEFR > 300 L/min
Watch for 4 hours for wearing off of beta
Continued wheezing
Continued dyspnea
PEFR <200 L/min
Pneumothorax, pneumomediastinum
Consider Intubation/BiPAP
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Obtunded
Sitting up/leaning forward with diaphoresis
Patient exhaustion