IV Magnesium for Prolonged Severe Asthma ASTHMA 1

IV Magnesium for Prolonged Severe Asthma

ASTHMA 1. 8 million ED visits yearly in US 100 million lost school/work days Can develop at any age 50% symptomatic by age 6

ASTHMA Pathophysiology—Complex Airway Inflammation Intermittent Airflow Obstruction Bronchial Hyperresponsiveness

Bronchodilators Bronchomotor tone balance of adrenergic and cholinergic systems Beta 2 agonists (Albuterol) Anti. Cholinergic agents (Atrovent) Beta 1 agonists (Epinephrine) ◦ Direct bronchodilitation ◦ Decreases secretions ◦ Bronchodilation

IV Magnesium Traditional Prehospital Uses ◦ Cardiac (torsades, pulseless v-fib) ◦ OB (PIH, toxemia, ecclampsia, Preterm labor) ◦ Hypomagnesemia

MAGNESIUM Smooth Muscle Relaxation ◦ Decreases influx at calcium channels ◦ Decreases neuromuscular transmission via decreased acetylcholine release at motor endplate Renal Excretion

IV Magnesium for Asthma Tx Dose 2 gm IV over 10 -20 min Which patients benefit? How do they benefit? ◦ Dilute in 100 cc NS ◦ Prolonged, severe asthma with incomplete response to initial therapies ◦ Resolution of bronchospasm ◦ Lower rates of hospitalization

Who Are These People? No Standardized Definition of “Prolonged and Severe” available for EMS In general—pts in distress and failing to improve with standard initial therapies

Magnesium ◦ ◦ ◦ Side Effects: CNS and respiratory depressant in BIG doses Vasodilitation – hypotension Flushing, sweating nausea Decreased contractility and heart block (Know where your Ca. CL is…)

Magnesium Who Can it Hurt? Patients on Digoxin Patients with Pre. Existing Heart Block Patients with Renal Impairment