Intraosseous access in an emergency

What it is

Intraosseous (IO) access places a rigid needle through the cortex into the marrow cavity, whose network of non-collapsible veins drains into the central circulation. It is the fastest reliable route when peripheral veins cannot be found in cardiac arrest, shock, major trauma, burns or status epilepticus, in children and in adults; resuscitation guidelines accept it when intravenous access fails or would be delayed. Any drug, fluid or blood product that can be given intravenously can be given IO, at comparable speed for most drugs. The common sites are the proximal tibia (the flat anteromedial surface below the tibial tuberosity), the distal tibia (above the medial malleolus), the proximal humerus in adults (the greater tubercle, with the arm adducted and the hand on the abdomen, which gives the fastest flow) and the distal femur in small children. Needles are placed with a powered driver, a spring-loaded device or a manual trocar needle. Correct position is shown by a sudden loss of resistance, a needle that stands without support, free flushing without swelling and, often, aspiration of marrow. Flow is usually slow under gravity and needs a pressure bag or syringe push. The needle is a bridge: replace it with a vein as soon as possible, and within about 24 hours.

Indications

• Cardiac arrest when an intravenous line is not already in place or cannot be placed quickly.
• Shock, major trauma or burns with failed or impossible peripheral access.
• Status epilepticus or other emergencies needing drugs within minutes.
• Critically ill infants and children, in whom veins are small and collapse.
• Blood samples in an emergency (type and crossmatch, gases, some chemistry), labelled as marrow.

Contraindications and precautions

• Fracture of the target bone, or a vascular injury proximal to it: fluid will leak; use another limb.
• Previous IO attempt or needle in the same bone within the last day or two: fluid escapes through the old hole.
• Infection, burns or cellulitis over the site: risk of osteomyelitis; choose another site.
• Bone disease such as osteogenesis imperfecta or osteopetrosis, or a prosthesis at the site: avoid.
• Unable to find the landmarks (severe obesity, oedema): choose another site rather than guessing.

Equipment

• IO device: powered driver with needle sets of different lengths, spring-loaded device or manual IO needle.
• Gloves and skin antiseptic.
• Extension set primed with saline, and a saline flush syringe.
• Pressure bag or syringe for infusion, and local anaesthetic for conscious patients as the protocol sets.
• Securing dressing, and a label with the time of insertion.

Step by step (and why)

1. Choose the site and find the landmarks by touch — the right spot avoids the growth plate and the joint.
2. Clean the skin and stabilise the limb without putting your hand behind the bone — a slip would hit your hand.
3. Insert at 90 degrees to the bone surface (humerus angled slightly downward) — this enters the marrow, not along the cortex.
4. Advance until a sudden loss of resistance, then stop — you are in the marrow; going on risks the far cortex.
5. Remove the stylet and check the needle stands unsupported — it confirms it is held in the bone.
6. Aspirate marrow for samples if needed, and label them as marrow — the laboratory must know the source.
7. Give local anaesthetic through the needle if the patient is conscious, as protocol sets — infusion into marrow hurts.
8. Flush and watch for swelling of the limb — free flushing without swelling proves the needle is in the cavity.
9. Infuse under pressure, secure, label the time — gravity flow is slow; the line is short-term only.

Common intraosseous sites

Complications

• Extravasation into the soft tissues, which can lead to compartment syndrome: check the limb often.
• Dislodgement or failure, especially with movement or during transport.
• Osteomyelitis or skin infection, rare and linked to long dwell times.
• Fracture, or injury to the growth plate in children if the site is wrong.
• Pain during infusion in conscious patients; fat embolism is described but rare.

Next step

• Get definitive intravenous or central access as soon as the patient is stable.
• Remove the IO needle within about 24 hours, then dress the site and check it for infection.
• Check the limb regularly for swelling, tense compartments or colour change, and stop the infusion if they appear.
• Tell the laboratory that samples are marrow: some results, such as the blood count, do not match venous blood.
• Call a senior if the first IO attempt fails; do not repeat in the same bone.

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Elsewhere in DurgiPedia

• Basic life support from the nursing side
• Shock: the clinical signs and the types
• Shock physiology

Connections

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Educational content; it does not replace supervised hands-on training, your institution's protocols or a prescriber's order. A procedure is learnt with a teacher and done only once you are trained to do it.

Sources: Intraosseous Vascular Access (StatPearls (NCBI Bookshelf), 2025).

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Representative model, for educational purposes only.