Olumide pidan, olumide adeola pidan

1. ASTHMA
Pediatric Critical Care Medicine
Emory University
Children’s Healthcare of Atlanta

2. Asthma
 Episodes of increased breathlessness, cough,
wheezing, chest tightness.
 Exacerbations may be abrupt or progressive
 Always related to decreases in expiratory (also
in inspiratory in severe cases) airflows
 Hallmarks: airway inflammation, smooth
muscle constriction and mucous plugs

3. Epidemiology
Most common chronic disease in the world: varies
between regions
More prevalent in westernized countries but more severe
in developing countries
Yr of cost 2005 >$11.5 billion per year
35/100.000 fatality, mostly pre-hospital & older pop
Seasonal exacerbation pattern but ICU admission remains
constant
<10% life threatening exacerbation: 2-20% with ICU
admission; 4% intubation
Reduction in mortality (63%) in the 1980’s due to inhaled
steroids

4. Asthma Prevalence
4

5. Pathophysiology
 Airway inflammation, smooth muscle constriction, and
airway obstruction
 VQ mismatch (<0.1)- decrease vent with normal perfusion
 Intrapulmonary shunt is prevented due to collateral
ventilation, hypoxic pulmonary vasoconstriction, rarely
functionally complete obstruction  mild hypoxemia
 Worsening of hypercapnea is indicative of impending
respiratory failure in combination of lactic acidosis
 Worsening of hypoxemia after beta-agonist is common due
to removal of hypoxic induced pulmonary vasoconstriction

6. Asthma

7. Histamine
Tryptase
PGD2
LTC4
IL-4
IL-5
IL-6
TNF-α
Eosinophilic cationic proteins
Major basic proteins
Platelet activating factor
LTC4, LTD4, LTE4
IL-3
IL-4
IL-5
GM-CSF

8. Pathophysiology
 Lactic acidosis:
 Changes in glycolysis due to high dose beta
agosist;
 Increased wob, anaerobic metabolism
 Coexisting profound tissue hypoxia
 Over production of lactic acid by the lungs
 Decrease lactate clearance due to hypoperfusion

9. Pathophysiology
 Significantly reduced: FEV1; FEV1/FVC, Peak
expiratory flow; maximal expiratory flow at 75%,
50% and 25%, and maximal exiratory flow
between 25% and 75% of the FVC
 Abnormally high airway resistance: 5-15x normal
due to shortening of airway smooth muscle,
airway edema and inflammation, excessive
luminal secretions.