Upload
praveen-kumar
View
145
Download
0
Embed Size (px)
DESCRIPTION
Olumide pidan, olumide adeola pidan
Citation preview
ASTHMA
Pediatric Critical Care MedicineEmory University
Children’s Healthcare of Atlanta
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
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
Asthma Prevalence
4
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
Asthma
HistamineTryptasePGD2
LTC4
IL-4IL-5IL-6TNF-α
Eosinophilic cationic proteinsMajor basic proteinsPlatelet activating factorLTC4, LTD4, LTE4
IL-3IL-4IL-5
GM-CSF
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
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.