Appendix A: Drugs used during the treatment of cardiac arrest

Question 1

What drugs are used in the treatment of cardiac arrest?

Answer 1

1. Adrenaline
2. Amiodarone
3. Calcium
4. Sodium Bicarbonate
5. Fluids
6. Fibrinolytics

Question 2

What is adrenaline?

Answer 2

• 1o sympathomimetic drug for CA mx
• Alpha-adrenergic effects:
  > Systemic vasoconstriction
  –> ^ coronary and cerebral perfusion pressures
• Beta-adrenergic effects (ino + chrono tropic)
  > ^ coronary and cerebral blood flow

Question 3

What is an inotrope?

Answer 3

Drugs affecting strength of cardiac contraction

• -ve inotrope: decreases strength of contraction
• +ve inotrope: ^ strength of cardiac contraction

Question 4

What is a chronotrope?

Answer 4

Drugs affecting heart rate

• -ve chrontrope: decreases HR
• +tve chronotrope: ^ HR

Question 5

Describe the administration of adrenaline for shockable and non-shockable rhythms

Answer 5

Shockable rhythms (VF/pVT)

• Dose: 1mg IV/IO (10 mL 1: 10 000 or 1 mL 1:1 000)
• Given after 2nd shock once compressions are resumed
• Repeated every alternate loop (3-5 min) once started
• Given without interrupting chest compressions

Non-Shockable (PEA/Asystole)

• Dose: 1mg IV/IO (10 mL 1: 10 000 or 1 mL 1:1 000)
• Given as soon as circulatory access is obtained
• Repeated every alternate loop (3-5 min) once started
• Given without interrupting chest compressions

Question 6

What is amiodarone?

Answer 6

• Membrane-stabilising anti-arrhythmic drug
• ^ duration of action potential and refractory period in atrial and ventricular myocardium
• Mild -ve inotropic action (peripheral vasodilation)

Question 7

Describe the administration of amiodarone for shockable and non-shockable rhythms

Answer 7

Shockable (VF/pVT)

• Dose: 300mg bolus IV/IO diluted in 5% dextrose (or compatible fluid) to volume of 20 mL
• Given during chest compressions after 3 defib attempts
• Further 150mg dose if VF/pVT persists after 5 defib attempts

Non-shockable (PEA/Asystole)
- Not indicated

Flush with 0.9% NaCl or 5% dextrose

Question 8

What is calcium?

Answer 8

• Vital role in cellular mechanisms underlying myocardial contraction

Question 9

Describe the administration of calcium

Answer 9

• Dose: 10mL 10% CaCl IV/IO
• Indicated for PEA caused specifically by ^K+, hypocalcaemia or overdose of Ca2+ channel blocking drugs
• Do not give Ca and NaHCO3 simultaneously by the same route

Question 10

What is sodium bicarbonate?

Answer 10

• Bicarbonate causes generation of Co2 which diffuses rapidly into cells and has the following effects:
  > Exacerbates intracellular cidosis
  > -ve inotropic effect on ischaemic myocardium
  > presents large osmotically-active Na load to compromised circulation and brain
  > left shift of O2 dissociation curve, inhibiting release of O2 to tissues

Question 11

Describe the administration of sodium bicarbonate in shockable and non-shockable rhythms

Answer 11

• Dose: 50 mmol IV/IO
• Routine use not recommended
• Consider use in shockable + non-shockable rhythms for:
  > CA associated with ^K+
  > Tricyclic overdose
• Repeat dose as necessary using acid-base analysis to guide therapy
• Do not give Ca + NaHCO3 simultaneously by same route

Question 12

What are fluids?

Answer 12

• Rapid infusion of fluids if hypovolaemia is suspected
• Use 0.9% NaCl or CSL OR blood for major haemorrhage
• Avoid dextrose
  
  • -> Causes ^BSL + is redistributed from intravascular space

Question 13

What are fibrinolytics?

Answer 13

• Not used routinely in CA
• Consider when CA is caused by proven/suspected acute PE
• Consider performing CPR for at least 60-90 min before termination of resuscitation attempts if given in these circumstances

Question 14

Describe the administration of fibrinolytic in shockable and non-shockable rhythms

Answer 14

• • Used in CA likely caused by PE
• Bolus dose during CPR
• Tenectaplase 500-600 microg per kg IV bolus
• Alteplase 10mg IV bolus - give further doses to total dose of 50mg at 15 min and 100mg by 2h