15 - Meds for Cardiovascular Life Support

causes of bradycardia

• increased parasympathetic tone

• profound hypoxia

  • ↓C.O.

  • ↓BP

  • ↓O₂ delivery

causes of tachycardia

• stress

• fever

• exercise

• hypovolemia

• hypoxemia

supraventricular tachycardia (SVT)

narrow QRS complexes

ventricular tachycardia (VT)

shockable rhythm

ventricular fibrillation (v-fib)

shockable rhythm

• treatment: CPR, de-fib, meds

asystole

NOT shockable

• treatment: CPR/AED, epinephrine

pulseless electrical activity (PEA)

NOT shockable

activity in the heart that is not tachycardia nor fibrillation

• treatment: epinephrine, continuous compressions, look for causes

pulseless electrical activity (PEA)

• “H” causes

• hypovolemia

• H⁺ (acidosis)

• hypoxia

• hypo-/hyperkalemia

• hypothermia

pulseless electrical activity (PEA)

• “T” causes

• tension pneumothorax

• tamponade (cardiac)

• toxins

• thrombosis

medications for resuscitation

drugs given during CPR immediately after rhythm is checked

• CPR continues during admin

• admin by bolus injection → 20 mL bolus IV, elevation of extremity

• intraosseous (IO) or endotracheal admin if IV not available

ACLS drugs

• cardiovascular support

ACLS drugs that alter C.O., rate, and PVR

examples:

• epinephrine

• vasopressin

• norepinephrine

• dobutamine

• dopamine

• digoxin

• milrinone

• nitroglycerin

• sodium nitroprusside

ACLS drugs

• arrest rhythms

ACLS drugs that control heart rate and rhythm

examples:

• lidocaine

• -lol drugs

• verapamil

• atropine

• magnesium

• dopamine

oxygen

• dosage

22-100% F_iO₂ via positive pressure ventilation or manual resuscitation bag

oxygen

• precautions

watch concentration and duration of exposure

• nitrogen washout

• radicals

epinephrine

• mechanism of action

• α and β effects

• peripheral vasoconstriction

• increased rate and force of contractions

epinephrine

• dosage

1 mg IV every 3-5 minutes

epinephrine

• precautions

• don’t mix with alkaline solutions

• can cause hypertension if patient is not in cardiac arrest

norepinephrine

• mechanism of action

• α vasocontriction

• β₁ inotropic effect

norepinephrine

• indications

• severe hypotension

• low PVR refractory to other sympathomimetics

norepinephrine

• dosage

0.50-1 mcg/min

• titrate so SBP ≥ 90

sodium bicarbonate

• mechanism of action

buffer base that neutralizes acid

sodium bicarbonate

• indications

• metabolic acidosis prior to cardiac arrest

• hyperkalemia

• drug overdose

sodium bicarbonate

• precautions

can cause respiratory acidosis

sodium bicarbonate

• dosage

1. 1 mEq/kg IV bolus

2. 0.5 mEq/kg IV every 10 minutes

positive inotropic drugs

• digoxin

• inamrinone

• dopamine

• dobutamine

digoxin

• indications

• atrial fibrillation

• atrial flutter

• slow ventricular response

digoxin

• dosage

10-15 mcg/kg lean body weight IV

• based on body size and renal function

digoxin

• precautions

can cause arrhythmias

inamrinone

• mechanism of action

• inhibits phosphodiesterase

• causes increased C.O. via positive inotropic effect and vasodilation

inamrinone

• indications

heart failure refractory to diuretics, vasodilators, and other inotropics

inamrinone

• dosage

1. IV load of 0.75 mg/kg

2. IV infusion of 5-15 mcg/kg/min

inamrinone

• precautions

can cause tachyarrhythmias, hypotension, and thrombocytopenia

dopamine

• indications

• symptomatic bradycardia

• hypotension (SBP 70-100) with signs of shock

dopamine

• dosage (low)

1-2 mcg/kg/min

• cerebral, renal, and mesenteric vasodilation

dopamine

• dosage (medium)

5-20 mcg/kg/min

• stimulates β₁ and α receptors, increases C.O.

dopamine

• dosage (high)

> 10 mcg/kg/min

• α-adrenergic effects

dobutamine (Dobutrex)

• mechanism of action

stimulates α₁ receptors

dobutamine (Dobutrex)

• indications

• CHF

• pulmonary congestion with SBP 70-100 without signs of shock

dobutamine (Dobutrex)

• dosage

2-20 mcg/kg/min

• HR should not increase >10% of baseline

atropine

• mechanism of action

parasympatholytic; increases HR

atropine

• indications

• increased parasympathetic tone due to advanced heart disease

• bradycardia

atropine

• dosage

IV bolus 1 mg every 3-5 minutes until HR is 60 bpm

• max dose: 3 mg

lidocaine (Xylocaine)

• substitution

can be used instead of amiodarone

lidocaine (Xylocaine)

• mechanism of action

makes heart more responsive to defibrillation

lidocaine (Xylocaine)

• indication

no response to epinephrine or defibrillation

lidocaine (Xylocaine)

• dosage

1-1.5 mg/kg every 3-5 minutes until 3 mg/kg

lidocaine (Xylocaine)

• precautions

can cause toxicity due to prolonged administration

amiodarone (Cordarone)

• indications

• SVT

• ventricular tachycardia

• v-fib

amiodarone (Cordarone)

• dosage

1 dose:

• 300 mg IV/IO bolus

2nd dose (if v-fib or pulseless VT):

• 150 mg every 3-5 minutes

3rd dose (if tachycardias):

• 150 mg in 10 minutes

• repeat for every VT

• 1 mg/min infusion for 6 hours

amiodarone (Cordarone)

• side effects

• hypotension

• bradycardia

procainamide (Pronestyl)

• mechanism of action

decreases automaticity in Purkinje fibers

procainamide (Pronestyl)

• dosage

IV infusion 1-4 mg/min

procainamide (Pronestyl)

• precautions

if given too fast or blood volume is too high, hypotension can occur

magnesium sulfate

• mechanism of action

affects sodium-potassium pump, calcium-channel blocker

treats Torsades de Pointes

magnesium sulfate

• dosage

arrest:

• 1-2 g in 10 mL of 5% dextrose over 5-20 minutes

no arrest

• 1-2 g in 50-100 mL of 5% dextrose over 5-60 minutes

verapamil (Calan, Isoptin)

• mechanism of action

negative chronotropic and inotropic effects

verapamil (Calan, Isoptin)

• dosage

2.5-5 mg IV bolus over 1-2 minutes

• max dose: 20 mg

verapamil (Calan, Isoptin)

• precautions

may cause severe hypotension and v-fib

diltiazem (Cardizem)

• mechanism of action

• negative chronotropic and inotropic effects

• controls ventricular response in patients with a-fib

diltiazem (Cardizem)

• dosage

IV bolus 0.25 mg/kg → infusion

diltiazem (Cardizem)

• precautions

pretreat with calcium, or hypotension can occur

adenosine (Adenocard)

• mechanism of action

• treats SVT

• does not treat a-fib, a-flutter, or VT

• half-life: 10 seconds

adenosine (Adenocard)

• dosage

1st dose:

• 6 mg bolus given over 1-3 seconds

(temporary pause of HR after admin)

2nd dose:

• 12 mg if no response within 1-2 minutes

(each admin MUST have saline flush!)

beta-blockers

• indications

• angina

• v-fib

beta-blockers

• mechanism of action

causes decreased HR and contractions, hypotension, and reduced O₂ consumption

beta-blockers

• contraindications

• bradycardia

• AV heart blocks

beta-blockers

• precautions

side effects increase when added to calcium-channel blockers, antihypertensives, and antiarrhythmics