Articles

Epinephrine (ACLS Pharmacology)

September 16, 2019


Epinephrine, commonly known as adrenaline,
is a chemical that narrows blood vessels and opens airways in the lungs. These effects can reverse severe low blood
pressure. Adrenaline is a hormone that is secreted mainly
by the medulla of the adrenal glands and functions primarily to increase cardiac output and to
raise blood glucose levels. Epinephrine is normally released during acute
stress, and its effects are known to prepare an individual for either “fight or flight”
which is why it’s a primary medication for non perfusing cardiac arrests. Epinephrine is used in Cardiac arrest arrhythmias
such as ventricular fibrillation and pulseless ventricular tachycardia, asystole and pulseless
electrical activity known as PEA. It can also be used in symptomatic bradycardia. It would be administered after atropine as
an alternative to infusing dopamine. Epi can also be administered to treat severe
hypotension. It’s been established that Epinephrine can
be administered when external pacing and atropine fail and when bradycardia causes hypotension. It is safe to be administered with phosphodiesterase
enzyme inhibitors. Epi is also an effective treatment for anaphylaxis. It’s recommended that it be combined with
large volumes of fluid, corticosteroids and antihistamines. Care should be given when administering epinephrine
in cases where raising the blood pressure and increasing heart rates may cause myocardial
ischemia, angina and increased demand for myocardial oxygen. It should be noted that high doses do not
improve neurological outcomes or survival rates and may actually contribute to post-resuscitation
complications like myocardial dysfunction. We commonly see high dose treatments with
poison or drug-induced shock. Epinephrine is available in 1:10,000 or 1:1,000
concentrations. For cardiac arrest, Epinephrine should be
delivered IV or IO at 1 mg which is 10 ML of 1:10,000 solution administered every 3
to 5 minutes during the resuscitation. Follow each dose of Epi with 20 ML of normal
saline as a flush, elevate the arm of delivery for 10 to 20 seconds after the dose is delivered. If Epi delivery is administered via endotracheal
tube, we’re going to deliver 2 to 2.5 mg diluted in 10 ml normal saline. Higher dose epi which is up to .2 mg/kg may
be used for specific indications like Beta Blocker or Calcium channel blocker overdose. If administering epinephrine as a continuous
infusion, initial rate is usually .1 to .5 mcg per kg per minute. Now an example of this would be: in a 90 kg
patient who would receive 9 to 45 mcg per minute titrated to a positive patient’s
response. Now for profound bradycardia or hypotension,
we want to deliver 2 to 10 mcg per minute titrated to the patient response delivering
a drip via an IV infusion. We want to add 1 mg of epinephrine (or l ml
of 1: l,000 solution) to a 250 ml or 500 ml of normal saline. For treatment of anaphylactic shock epinephrine
1:1,000 is given at .01 mg per kg via intramuscular delivery.

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