Drugs for cardiac arrest Flashcards
When and how do you give adrenaline in cardiac arrest?
How?
1 mg (10 mL 1:10,000 or 1 mL 1:1,000) IV/O
When?
Shockable (VF/PVT)
* Given after the 2nd shock once compressions have been resumed
Repeated every alternate loop (3-5 min) once started
* Given without interrupting chest compressions
Non-Shockable (PEA/Asystole)
* Given as soon as circulatory access is obtained
* Repeated every alternate loop (3-5 min) once started
Given without interrupting chest compressions
How does adrenaline work in cardiac arrest and what are potential downsides?
Its alpha-adrenergic effects cause systemic vasoconstriction, which increases coronary and cerebral perfusion pressures. The beta-adrenergic actions of adrenaline (inotropic, chronotropic) may increase coronary and cerebral blood flow,
but
1. concomitant increases in myocardial oxygen consumption
2. and ectopic ventricular arrhythmias (particularly in the presence of acidaemia),
3. transient hypoxaemia because of pulmonary arteriovenous shunting,
4. impaired microcirculation,
5. and increased post-cardiac arrest myocardial dysfunction may offset these benefits.
When and how do you give amiodarone in cardiac arrest?
Dose: 300 mg bolus IV/O ideally diluted in 5%
dextrose (or other suitable solvent) to a volume of 20 mL
3rd shock: Given during chest compressions after three
defibrillation attempts (shock refractory)
5th shock: Further dose of 150 mg if VF/pVT persists after five defibrillation attempts
How does amiodarone work in cardiac arrest and what are some potential downsides?
How? Amiodarone is a membrane-stabilising anti-arrhythmic drug that increases the duration of the action potential and refractory period in atrial and ventricular myocardium.
Atrioventricular conduction is slowed, and a similar effect is seen with accessory pathways.
Downsides?
Amiodarone has a mild negative inotropic action and causes peripheral vasodilation through non-competitive alpha-blocking effects.
When amiodarone is unavailable, what is another option?
Consider an initial dose of 100 mg (1-1.5 mg kg) of lignocaine for VF/pVT refractory to three shocks.
Give an additional bolus of 50 mg if necessary.
The total dose should not exceed 3 mg/kg during the first hour.
How and when do you give calcium in cardiac arrest?
Dose: 10 mL 10% calcium chloride (6.8 mmol Ca2+) IV/IO (or calcium gluconate)
Indicated for PEA caused specifically by hyperkalaemia, hypocalcaemia or overdose of calcium channel blocking (verapamil, diltiazem, -pine drugs like amlodipine)
How does calcium work in cardiac arrest?
Downsides?
What shouldn’t giving it the same time?
How? Calcium plays a vital role in the cellular mechanisms underlying myocardial contraction.
Downsides? High plasma concentrations achieved after injection may be harmful to the ischaemic myocardium and may impair cerebral recovery. Do not give calcium solutions and sodium bicarbonate simultaneously by the same route.
How is sodium bic given?
When do you give sodium bicarbonate in cardiac arrest?
What is the downside of sodium bicarbonate?
What don’t you give at same time in same route?
Dose: 50 mmol (50 mL of an 8.4% solution) IV/IO
Consider it in shockable / non-shockable rhythms for:
1. Cardiac arrest with hyperkalaemia (shifts k+)
2. Tricyclic overdose (TCAs block sodium channels which Na+ Bic gives excess sodium)
Repeat as necessary but monitor acid-base
Do not give calcium solutions and sodium bicarbonate simultaneously by the same route
What is the downsides? Bicarbonate produces excess carbon dioxide which:
1. it exacerbates intracellular acidosis
2. it produces a negative inotropic effect on ischaemic myocardium
3. it presents a large, osmotically-active sodium load to an already compromised circulation and brain
4. it produces a shift to the left in the oxygen dissociation curve, further inhibiting release of oxygen to the tissues.
What is the best treatment for acidaemia in cardiac arrest?
Compressions and limited benefit with ventilation
What are the use of fluids in cardiac arrest? And what fluids?
If hypovolaemia is suspected, use 0.9% sodium chloride or Hartmann’s solution or blood for major haemorrhage
20ml/kg like 1.5 litres
What fibrinolytics are used for PE and how?
Should they be used routinely in cardiac arrest?
How long should you consider doing CPR after giving them?
Summary: Consider fibrinolytic therapy when cardiac arrest is caused by proven or suspected acute pulmonary embolus.
What?
Tenecteplase 500-600 mcg/kg IV bolus
Alteplase (r-tPA) 10 mg IV bolus. (Give further doses to a total dose of 50 mg at 15 min and 100 mg by 2 h.)
How?
Give as bolus
Should they be used routinely?
Fibrinolytic therapy should not be used routinely in cardiac arrest.
How long should you consider doing CPR?
If a fibrinolytic drug is given in these circumstances, consider performing CPR for at least 60-90 min before termination of resuscitation attempts. Ongoing CPR is not a contraindication to fibrinolysis.
