What are the medications used in Pediatric Advanced Life Support (PALS) and when are they administered for different cardiac rhythms?

PALS Medications and Administration Algorithm by Cardiac Rhythm

Shockable Rhythms (VF/Pulseless VT)

For ventricular fibrillation or pulseless ventricular tachycardia, prioritize immediate defibrillation and high-quality CPR before any medication administration, then follow a structured sequence of epinephrine and antiarrhythmics. 1

Initial Management Sequence

• Start CPR immediately for 2 minutes while establishing IO/IV access 1
• Deliver first shock before any medications 1
• Resume CPR immediately after shock for 2 minutes 1
• Consider advanced airway during CPR cycles 1

Medication Administration Order

First medication: Epinephrine

• Administer after rhythm check following 2nd or 3rd shock if VF/pVT persists 1, 2
• Dose: 0.01 mg/kg IO/IV (0.1 mL/kg of 1 mg/mL concentration) 1
• Maximum single dose: 1 mg 1
• Repeat every 3-5 minutes throughout resuscitation 1, 2
• Alternative route if no IO/IV access: Endotracheal dose 0.5 mg/kg (0.1 mL/kg of 1 mg/mL concentration), though this route is less reliable 1, 3

Second medication: Antiarrhythmic (for shock-refractory VF/pVT)

• Administer after CPR cycle following shock when rhythm remains VF/pVT despite epinephrine and defibrillation 1
• Choose either Amiodarone OR Lidocaine (not both initially) 1

Amiodarone:

• Dose: 5 mg/kg IO/IV bolus 1, 4
• May repeat up to 2 additional times for persistent refractory VF/pulseless VT 1

Lidocaine (alternative to amiodarone):

• Initial loading dose: 1 mg/kg IO/IV 1
• Maintenance infusion: 20-50 mcg/kg per minute 1
• Repeat bolus dose if infusion initiated >15 minutes after initial bolus 1

Critical Timing Considerations for Shockable Rhythms

• Never delay defibrillation to establish vascular access or administer medications 2
• Defibrillation is the definitive treatment for VF/pVT; medications are adjunctive 1, 2
• Continue epinephrine every 3-5 minutes (operationally every second CPR cycle) throughout resuscitation 2

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Non-Shockable Rhythms (Asystole/PEA)

For asystole and pulseless electrical activity, administer epinephrine as soon as IO/IV access is established—this is the priority medication and should not be delayed. 2, 5, 6

Initial Management Sequence

• Start CPR immediately for 2 minutes while establishing IO/IV access 1
• Consider advanced airway during CPR cycles 1

Medication Administration Order

Primary medication: Epinephrine

• Administer as soon as feasible after establishing IO/IV access 2, 5, 6
• Optimal timing: ≤2 minutes from pulse loss is associated with improved outcomes 5
• Dose: 0.01 mg/kg IO/IV (0.1 mL/kg of 1 mg/mL concentration) 1
• Maximum single dose: 1 mg 1
• Repeat every 3-5 minutes throughout resuscitation 1, 2
• Alternative route if no IO/IV access: Endotracheal dose 0.5 mg/kg (0.1 mL/kg of 1 mg/mL concentration) 1

Evidence Supporting Early Epinephrine in Non-Shockable Rhythms

• Each minute delay in epinephrine administration decreases survival by 5% in pediatric in-hospital cardiac arrest with non-shockable rhythms 6
• Early epinephrine (≤2 minutes) is associated with higher rates of ROSC, improved functional outcomes, and lower new morbidity compared to administration >2 minutes 5
• Epinephrine administration >5 minutes is associated with significantly worse outcomes (21% vs 33% survival) 6

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Universal PALS Medication Principles

Route of Administration Priority

1. Intravenous (IV) access is preferred 2
2. Intraosseous (IO) access is equally acceptable if IV unsuccessful 2
3. Endotracheal route is least reliable and requires higher doses 1, 3
4. Never delay CPR or defibrillation to establish vascular access 2

Additional Medications (Context-Dependent)

Atropine:

• Dose: 0.02 mg/kg IO/IV (minimum 0.1 mg, maximum single dose 0.5 mg) 7
• Consider for bradycardia with poor perfusion, though not routinely used in cardiac arrest 7

Calcium:

• Indications unchanged from previous guidelines; use for documented hypocalcemia, hyperkalemia, hypermagnesemia, or calcium channel blocker toxicity 3
• Not a first-line cardiac arrest medication 3

Sodium Bicarbonate:

• Not a first-line medication 3
• Consider only when patient fails to respond to advanced life support including high-quality CPR and epinephrine 3
• May be helpful in prolonged arrest or known metabolic acidosis, but should not replace efforts to maximize tissue perfusion 3

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Critical Pitfalls to Avoid

Common Errors in PALS Medication Administration

• Do not use high-dose epinephrine routinely (>0.01 mg/kg or >1 mg); studies show no benefit and potential harm 8, 9
• Do not delay epinephrine in non-shockable rhythms—every minute counts 5, 6
• Do not give antiarrhythmics before establishing shock-refractory VF/pVT—they are only indicated after failed defibrillation attempts 1
• Do not interrupt high-quality CPR for medication administration—chest compressions are more important than any drug 2
• Do not use vasopressin—it offers no advantage over epinephrine 2

Important Outcome Considerations

• Epinephrine increases ROSC but does not improve long-term neurological outcomes 2
• Neither amiodarone nor lidocaine improve long-term survival despite improving short-term ROSC rates 2
• The primary goal remains high-quality CPR with minimal interruptions; medications are adjunctive 2
• Treat reversible causes (Hs and Ts) throughout resuscitation 1