ACLS Provider: Course

Intraosseous (IO) Access

When intravenous (IV) access cannot be quickly obtained during an emergency, intraosseous (IO) access provides a rapid, reliable route for the delivery of medications, fluids, and blood products. By accessing the rich vascular network of the bone marrow, IO insertion offers a life-saving alternative during cardiac arrest, severe shock, or trauma—particularly in pediatric or critically ill patients where peripheral veins may be collapsed or inaccessible.

When to Use IO Access

IO access is indicated in any situation where vascular access is needed urgently and IV attempts have failed or are impractical. It is especially valuable in:

• Cardiac arrest of any rhythm.
• Severe shock (hypovolemic, distributive, or cardiogenic).
• Major trauma or burns with poor peripheral perfusion.
• Prolonged or unsuccessful IV attempts (>2 tries or >90 seconds).

Importantly, all medications and fluids administered intravenously can be delivered via the IO route using identical dosing protocols.

Contraindications

IO access is not appropriate in the presence of certain localized or systemic issues, such as:

• Fracture at or above the intended insertion site.
• Previous IO insertion at the same site within 24 hours.
• Skin or bone infection near the site (e.g., cellulitis, osteomyelitis).
• Inability to clearly identify anatomical landmarks.

Common IO Insertion Sites

The choice of insertion site is based on the patient's age, anatomy, and clinical condition. The most frequently used sites include:

• Proximal tibia: 2–3 cm below the tibial tuberosity on the flat medial surface. Most common in adults and children.
• Proximal humerus: Just below the shoulder joint at the greater tubercle. Offers faster systemic uptake, but requires good positioning.
• Distal tibia: 3 cm above the medial malleolus. A backup site if proximal tibia is contraindicated.

Insertion Technique (Using a Power Drill Device)

1. Identify the insertion site and cleanse with antiseptic solution.
2. Position the needle at a 90° angle to the bone surface.
3. Advance the needle with gentle, steady pressure using a powered IO drill until a “pop” or loss of resistance is felt (indicating entry into the marrow).
4. Remove the inner stylet while leaving the catheter in place.
5. Aspirate marrow (optional but helpful), then flush with 5–10 mL of saline to confirm patency.
6. Secure the IO catheter with a stabilization device or adhesive dressing.

Medication and Fluid Delivery

ACLS medications—including epinephrine, amiodarone, atropine, and lidocaine—can be administered via IO using standard IV doses. Always follow each medication with a forceful saline flush to ensure delivery into central circulation. Continuous infusions may require pressure bags or manual pressure, as gravity alone is insufficient.

Monitoring and Complications

While IO access is generally safe, it requires vigilant site monitoring. Complications may include:

• Extravasation: Swelling or poor flow may indicate improper placement—stop infusion and relocate if needed.
• Compartment syndrome: Rare but serious complication from fluid leakage into soft tissue.
• Osteomyelitis: Risk increases after 24 hours—IO access should be temporary.
• Fracture or growth plate injury: Especially in pediatric patients or those with bone fragility.

Key Considerations

• IO access is a bridge to IV access—not a permanent solution. Transition as soon as feasible.
• Use lidocaine (2% without epinephrine) for site anesthesia if the patient is conscious.
• Always confirm correct placement before drug delivery.
• Remove the IO device within 24 hours to minimize infection risk.