What medication should be administered intraosseously (intraosseous access) to a newborn with a heart rate of bradycardia (40 beats per minute) that remains unchanged after chest compressions and endotracheal intubation?

Epinephrine Administration for Neonatal Bradycardia

Administer epinephrine (adrenaline) intraosseously at a dose of 0.01-0.03 mg/kg immediately, as this is the indicated medication when a newborn's heart rate remains below 60 bpm despite adequate ventilation and chest compressions. 1, 2

Rationale for Epinephrine

• Epinephrine is the only medication indicated when adequate ventilation and chest compressions have failed to increase the heart rate to ≥60 bpm in a newborn 1
• The International Consensus on Cardiopulmonary Resuscitation and American Heart Association both recommend epinephrine as the first-line vasoactive agent for neonatal cardiac arrest with persistent bradycardia 1, 2
• The intraosseous route is a reasonable alternative to umbilical venous catheterization when umbilical access is not immediately available 1

Dosing and Administration

• The recommended IV/IO dose is 0.01-0.03 mg/kg (for this 3 kg infant: 0.03-0.09 mg) 1, 2
• Administer as soon as possible, ideally within 5 minutes of starting chest compressions, as every minute of delay decreases survival and favorable neurological outcomes 1, 2
• Repeat doses every 3-5 minutes if heart rate remains <60 bpm, using the same IV/IO dose 1, 2
• Higher doses (>0.03 mg/kg) are not recommended due to increased mortality risk without improved survival 2

Why Not the Other Options

• Atropine (Option A): Not indicated for neonatal resuscitation with bradycardia secondary to hypoxia/asphyxia; atropine is used for vagally-mediated bradycardia in specific pediatric situations but has no role in hypoxic neonatal arrest 3
• Naloxone (Option C): Not a first-line resuscitation medication; only considered after successful resuscitation if there is documented maternal opioid use within 4 hours of delivery and persistent respiratory depression despite adequate ventilation 1
• Sodium bicarbonate (Option D): Routine administration is not recommended in neonatal cardiac arrest; only indicated for specific situations like documented hyperkalemia or sodium channel blocker toxicity, not for initial resuscitation 1

Evidence Supporting Intraosseous Route

• Animal studies demonstrate equivalent efficacy between intraosseous and intravenous epinephrine administration in newborn lambs, with similar time to ROSC, plasma epinephrine levels, and hemodynamic responses 4, 5
• Intraosseous epinephrine achieves comparable pharmacokinetics to central venous administration with clearance rates of 186 ml/kg/min (IO) versus 174 ml/kg/min (IV) 5
• Comparative studies show intraosseous access is faster than peripheral IV placement (mean 60 seconds vs 4-5 minutes) when performed by experienced providers 6, 7

Critical Pitfall

• One important caveat: In hypovolemic cardiac arrest, tibial intraosseous epinephrine may be less effective due to potential sequestration in the bone, with only 14% ROSC versus 71% with IV administration 8
• However, in this normovolemic newborn with precipitous delivery, intraosseous epinephrine remains highly effective and appropriate 4, 8