Flush IO After Administering Epinephrine in Cardiac Arrest
Yes, you must flush the intraosseous (IO) line immediately after administering epinephrine during cardiac arrest with at least 5 mL of normal saline to ensure the drug reaches the central circulation. 1
Why Flushing is Mandatory
The American Heart Association explicitly recommends following each medication bolus with a flush of at least 5 mL of normal saline to ensure complete drug delivery during cardiac arrest. 1 Without this flush, epinephrine may remain in the IO line or peripheral vasculature and never reach therapeutic concentrations in the central circulation where it needs to exert its alpha-adrenergic vasoconstrictor effects. 2
The standard protocol is: give the full 10 mL epinephrine bolus (1 mg in 1:10,000 solution) rapidly, followed immediately by a 20 mL normal saline flush. 2 This larger flush volume (20 mL rather than just 5 mL) is specifically recommended to ensure delivery to the central circulation during active CPR. 2
IO-Specific Considerations
IO access requires manual pressure or an infusion pump to administer the flush effectively, as IO routes may require additional pressure for adequate flow compared to IV access. 3
All intravenous medications can be administered intraosseously with onset of action and drug levels comparable to venous administration, but only if properly flushed. 3
The American Heart Association confirms that epinephrine or norepinephrine may be administered through an IO line if central venous access is not readily accessible, particularly in pediatric septic shock after fluid resuscitation. 3
Timing and Technique During CPR
Minimize interruptions in chest compressions during drug delivery—the pause should be ≤10 seconds. 2
Continue high-quality CPR while preparing and administering epinephrine and the flush. 2 Drug delivery can occur during ongoing compressions; you do not need to stop CPR to give the medication or flush. 2
Do not delay epinephrine beyond 5 minutes from the start of compressions, as each minute of delay significantly decreases survival and neurologic outcomes. 1
Evidence for Flush Volume
Recent animal data in newborn lambs demonstrated that 3 mL/kg flush volume was associated with three times faster return of spontaneous circulation compared to 1 mL flush (adjusted HR 3.5,95% CI 1.27-9.71). 4 The larger flush volume resulted in higher plasma epinephrine concentrations and hastened time to ROSC. 4 While this study used umbilical venous catheters in neonates, the principle applies to IO access: adequate flush volume is critical for drug delivery.
Common Pitfalls to Avoid
Never skip the saline flush—without it, the drug may remain in the IV/IO line and never reach the patient. 2
Do not use inadequate flush volumes—at minimum 5 mL, but 20 mL is recommended for cardiac arrest to ensure central delivery. 2, 1
Do not interrupt chest compressions for more than 10 seconds to give epinephrine and flush; these can be administered during ongoing CPR. 2
Do not delay transitioning to central venous access if the resuscitation is prolonged, though IO can be used safely for the duration needed in emergency situations. 3