1.8 million ED visits yearly in US 100 million lost school/work days Can develop at any age 50% 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 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