Asthma
PICU Resident Talk
I.
II.
III.
Etiology, epidemiology, natural history
a. Most common chronic disease in children.
b. Triggered by exercise, URI, allergens, weather changes, smoke, aspirin, beta
adrenergic blocking drugs
c. Early onset (<3 yo), parental history, atopic dermatitis, sensitization to
aeroallergens – least likely to outgrow asthma
d. Risk factors: race, socio-economic status, previous ICU/intubation, failure to
recognize symptoms, syncope with previous attack
e. Bronchial hyperresponsiveness, exaggerated bronchial obstructive response
f. IgE-mediated allergen induces immediate obstruction, with persistent late-phase
4-12 hours later
g. Bronchial hyperresponsiveness increases with late-phase responses to allergens
and with viral URI
h. Recurrent wheezing frequent in infants with RSV
Diagnosis
a. Signs of severe obstructions in acute exacerbation: retractions, inability to speak
whole phrases, cyanosis, quiet breath sounds (with other signs) prolonged
expiratory phase, PEF<30% predicted
b. Atelectasis associated with acute exacerbation does not usually require
bronchoscopy, antibiotics, or chest PT
c. Classifications of asthma severity and definitions:
Treatment
a. Acute exacerbation: inhaled beta agonists
b. Systemic corticosteroids for severe exacerbation
c. Toxicity from adrenergic agonists (tremors, tachycardia, hypokalemia
d. Criteria for ICU admission: asthma score >6, decreased mental status, inability to
tolerate q2h nebs
e. Protocol for Status asthmaticus: continuous nebs, IV steroids. May use
anticholinergics. Pulmonary consult.
f. Intubation rarely needed – ventilate at lower rates and higher volumes. Tolerate
higher PCO2. Sedate – not with morphine (histamine release)