1.8 million ED visits yearly in US

100 million lost school/work days

Can develop at any age50% symptomatic by age 6

Pathophysiology—Complex

Airway Inflammation

Intermittent Airflow Obstruction

Bronchial Hyperresponsiveness

Bronchomotor tone balance of adrenergic and cholinergic systems

Beta 2 agonists (Albuterol)◦ Direct bronchodilitation

AntiCholinergic agents (Atrovent)◦ Decreases secretions◦ Bronchodilation

Beta 1 agonists (Epinephrine)

Traditional Prehospital Uses◦ Cardiac (torsades, pulseless v-fib)

◦ OB (PIH,toxemia, ecclampsia, Preterm labor)

◦ Hypomagnesemia

Smooth Muscle Relaxation◦ Decreases influx at calcium channels◦ Decreases neuromuscular transmission via

decreased acetylcholine release at motor endplate

Renal Excretion

Dose 2gm IV over 10 -20 min◦ Dilute in 100cc NS

Which patients benefit?◦ Prolonged, severe asthma with incomplete

response to initial therapies

How do they benefit?◦ Resolution of bronchospasm◦ Lower rates of hospitalization

No Standardized Definition of “Prolonged and Severe” available for EMS

In general—pts in distress and failing to improve with standard initial therapies

Side Effects:◦ CNS and respiratory depressant in BIG doses

◦ Vasodilitation – hypotension Flushing, sweating nausea

◦ Decreased contractility and heart block(Know where your CaCL is…)

Who Can it Hurt?Patients on Digoxin

Patients with PreExisting Heart Block

Patients with Renal Impairment