Definition: Non-collapsible venous access via the medullary cavity of long bones; provides rapid entry into systemic circulation via non-collapsing bone marrow venous sinusoids.
Primary Indication: Critically ill/injured pts (pediatric or adult) requiring emergent vascular access when peripheral IV (PIV) access fails or cannot be rapidly established.
Pediatric arrest/decompensated shock: Attempt PIV for <90 seconds or max 2 attempts→ switch immediately to IO access. c
Adult cardiac arrest/trauma shock: Standard alternative when PIV is unsuccessful. Faster and safer to place than a central venous catheter (CVC) during active cardiopulmonary resuscitation (CPR).
Duration: Temporary bridge only. Must be removed as soon as definitive vascular access (PIV or CVC) is secured, strictly within 24 hours (minimizes infection risk).
Contraindications
Absolute:
Bone fracture in the target extremity (infusate extravasates into soft tissue → compartment syndrome).
Prior IO attempt in the same bone (fluid leaks through the previous cortical hole).
Local infection, cellulitis, or severe burn overlying insertion site.
Underlying severe bone disorder (e.g., osteogenesis imperfecta, severe osteopetrosis).
Relative:
Inability to palpate anatomical landmarks.
Prior orthopedic hardware/prosthesis near the target site.
Preferred Anatomical Sites
Proximal Tibia (Most Common Overall & Preferred in Pediatrics):
Landmark: Flat anteromedial surface, 1–2 cm distal and medial to the tibial tuberosity.
Advantage: Broad, flat surface; thin overlying subcutaneous tissue; far from the airway and CPR chest compressions.
Distal Tibia:
Landmark: Flat surface approximately 2–3 cm proximal to the medial malleolus.
Advantage: Useful in adults and older children if proximal tibia is fractured or inaccessible.
Proximal Humerus (Preferred in Conscious Adults):
Landmark: Greater tubercle of the humerus (arm adducted and internally rotated).
Advantage: Higher flow rates due to proximity to the SVC/heart; lower pain during infusion compared to tibial sites.
Distal Femur:
Used primarily in infants/neonates: 1–2 cm superior to the external condyle in the midline.
Sternum:
Restricted to adults; requires specialized dedicated devices (e.g., FAST1). Contraindicated in children due to high risk of mediastinal and great vessel penetration.
Insertion Technique & Confirmation
Technique:
Cleanse site with chlorhexidine/povidone-iodine.
Insert IO needle at a 90-degree angle to the bone cortex.
Advance manually (until a sudden “give” or loss of resistance) or using a powered driver.
Signs of Correct Placement:
Sudden loss of resistance upon penetrating the bony cortex.
Needle remains firmly upright without support.
Aspiration of bone marrow (confirms placement, though failure to aspirate does not exclude correct placement).
Smooth, resistance-free flush with normal saline without local soft-tissue extravasation.
Pain Management (Alert Patients):
Infusion of 2% preservative-free lidocaine IO over 1–2 minutes prior to fluid/medication bolus (blunts the severe visceral pain of marrow cavity expansion).
Pharmacokinetics, Fluids, & Laboratory Testing
Medications & Fluids:
Any drug, blood product, or fluid that can be administered via PIV or CVC can be given via IO at the identical dose, concentration, and rate.