8.2 Intraosseous Access
Key Takeaways
- Intraosseous (IO) access provides rapid emergency vascular access when peripheral IV attempts fail or will delay critical therapy; marrow venous channels empty into the central circulation.
- Common adult insertion sites include the proximal tibia and proximal humerus (humeral head region); follow device-specific landmarks and training competency.
- Conscious patients often experience significant pain with IO fluid/medication infusion—consider IO lidocaine (or equivalent per protocol) before rapid infusions when time and condition allow.
- IO is temporary: remove as soon as reliable IV or CVAD access is established, typically within about 24 hours, and sooner if complications occur.
- Contraindications include fracture of the target bone, infection/burn at the insertion site, prior IO attempt in the same bone (recent), and other device/policy exclusions such as orthopedic hardware through the site.
Intraosseous access on the CRNI blueprint
Domain 2A.2.d covers intraosseous (IO) access—emergency placement of a specialized needle into the medullary cavity so fluids and medications can reach the central circulation via marrow venous sinusoids. For infusion nurses, IO competence includes indications, sites, contraindications, pain control principles, complications, and timely removal.
Quick Answer: Use IO access when urgent intravascular therapy is needed and IV access is delayed or fails. Marrow flow reaches the central circulation rapidly. Preferred adult sites often include proximal tibia and proximal humerus. Manage infusion pain in conscious patients (commonly IO lidocaine per protocol before forceful flush/infusion). Remove ASAP once durable IV or CVAD access exists—typically within ~24 hours. Do not place IO through fractured bone, infected/burned skin, or a bone with a recent prior IO attempt.
Why IO works
The medullary cavity contains a non-collapsible venous plexus. Even in profound shock when peripheral veins are collapsed, marrow spaces often remain accessible. Drugs and fluids administered IO enter marrow venous channels and transit to the central venous system, allowing:
- Crystalloid and colloid resuscitation
- Blood products per protocol
- Emergency medications (including many ACLS drugs when IV is unavailable)
- Laboratory sampling in some systems (know local capability and hemolysis/interpretation limits)
Exam principle: IO is functionally vascular access, not an intramuscular injection. Doses for many emergency drugs follow IV dosing once IO is confirmed—always verify current emergency protocols and drug-specific exceptions.
Indications
Consider IO when any of the following apply and clinicians are trained/authorized:
- Cardiac arrest or peri-arrest with failed/delayed PIV
- Shock, major trauma, severe dehydration, status epilepticus, anaphylaxis, or other time-critical states needing immediate meds/fluids when IV is not rapidly obtainable
- Difficult vascular access with high acuity (multiple failed sticks delaying care)
- Situations where waiting for ultrasound PIV or central access would harm the patient relative to rapid IO placement
IO is not first-line for routine elective infusions in stable patients with easy veins. It is a bridge, not a long-term device class like PICCs or ports.
Common insertion sites
Know adult high-yield sites and the idea that pediatric landmarks differ (e.g., distal femur options in some protocols). Focus on concepts tested for general infusion nursing:
| Site | Typical adult role | Landmark concept (device training required) |
|---|---|---|
| Proximal tibia | Classic, widely taught emergency site | Flat medial surface distal to tibial tubercle/plateau per product training—avoid growth plate concepts in pediatrics |
| Proximal humerus (humeral head) | Often excellent flow; useful in adults | Greater tubercle region with arm positioning per IFU; may achieve high flow rates |
| Distal tibia / other approved sites | Alternate when primary contraindicated | Only if trained and device-indicated |
| Sternum | Specialized devices/settings | Not a casual bedside default; requires specific system training |
Humeral vs tibial flow: Humeral IO often supports higher flow for resuscitation in adults when correctly placed and flushed—exam stems may prefer humeral access for large-volume needs when not contraindicated and the provider is competent.
Confirmation of placement (principles)
- Sudden loss of resistance / correct depth per device feedback (manual or powered driver)
- Needle stands firmly at 90° without wobble (context-dependent)
- Aspiration of marrow/blood may occur but absence of aspirate does not always rule out correct placement
- Free flush without soft-tissue swelling; watch for extravasation into calf/arm soft tissue
- Ability to infuse with expected resistance profile after initial pressure to clear marrow
If extravasation is suspected: stop infusion, assess limb compartments, remove IO, do not use that bone again for another IO, escalate care for compartment syndrome risk.
Technique and asepsis (high-level)
- Identify indication; obtain authorization per emergency scope/policy.
- Select site free of contraindications; expose and stabilize limb.
- Skin antisepsis; sterile or clean technique per emergency protocol and product IFU (emergency speed still requires basic antisepsis).
- Insert with trained method (manual, impact-driven, or powered driver).
- Remove stylet; attach extension/needleless connector if used; aspirate if protocol requires.
- Rapid syringe flush (often 5–10 mL saline in adults—follow protocol) to clear marrow and establish flow; expect resistance initially.
- Secure device; protect from dislodgement during CPR/transport.
- Begin ordered infusions/meds; monitor site continuously for swelling.
- Plan definitive IV/CVAD replacement immediately after stabilization begins.
Pain with IO infusion in conscious patients
Insertion pain can be significant, but infusion pain—especially with the initial flush and rapid volume—is often worse in awake patients because pressure expands the marrow cavity.
Lidocaine considerations (exam-critical):
- When the patient is conscious and time allows, many protocols administer preservative-free lidocaine IO slowly before forceful flush/infusion to anesthetize the marrow space.
- Follow dose limits, concentration, and aspiration/dwell steps in organizational ACLS/emergency IO protocols—do not improvise toxic doses.
- In cardiac arrest, do not delay critical epinephrine/defibrillation pathways for pain control rituals; priorities differ by consciousness and rhythm algorithm.
- Document drug, dose, route (IO), and response.
Exam trap: Ignoring severe infusion pain in a conscious trauma patient and “pushing through” without protocolized analgesia/anesthesia of the IO space when time and hemodynamics allow intervention.
Contraindications
| Contraindication | Why |
|---|---|
| Fracture of the target bone | Fluid escapes fracture site; ineffective delivery; soft-tissue injury |
| Infection, burn, or cellulitis at site | Seeds marrow/bone infection; poor barrier |
| Prior IO attempt in the same bone (recent) | Extravasation risk through prior hole; choose another bone |
| Orthopedic hardware / prosthesis through site | Mechanical obstruction; damage; poor placement |
| Severe osteoporosis or osteogenesis imperfecta (relative/device-specific) | Fracture and malposition risk—follow product cautions |
| Inability to identify landmarks | Wrong-space placement risk |
If the tibia is fractured, move to an uninjured alternate site (e.g., humerus) rather than forcing tibial IO.
Dwell time and removal
IO access is temporary emergency access.
- Remove as soon as reliable peripheral IV or CVAD access is obtained and functioning for needed therapy.
- Many references and policies target removal within 24 hours of insertion (sooner preferred).
- Prolonged dwell increases risk of osteomyelitis, extravasation injury, and compartment syndrome.
- On removal: use aseptic technique, apply sterile dressing, monitor site, document time in/out and complications.
- Do not leave IO “for convenience” after multiple working PIVs are present.
Complications
| Complication | Recognition | Priority actions |
|---|---|---|
| Extravasation / infiltration | Progressive limb swelling, coolness, leakage, high pump pressures | Stop infusion; remove IO; elevate/assess compartments; notify provider |
| Compartment syndrome | Severe pain, tense compartments, neurovascular change | Emergency surgical evaluation—time critical |
| Infection / osteomyelitis | Local infection signs, fever, delayed pain after removal | Culture/treat; imaging as ordered; prevention via short dwell + asepsis |
| Growth plate injury (pediatrics) | Wrong landmarking in children | Pediatric-specific training; correct site selection |
| Fracture | Crack, deformity, loss of resistance abnormal pattern | Stop; immobilize; alternate access; imaging |
| Dislodgement | Needle movement, loss of flow | Secure better next time; replace only if still indicated at new site |
IO vs other emergency options
| Option | When it wins |
|---|---|
| Ultrasound-guided PIV | Difficult veins but patient stable enough for minutes of skilled attempt |
| IO | Seconds matter; collapse; arrest; multiple failed sticks |
| Non-tunneled CVC | Need central access, monitoring, multi-lumen critical care—after airway/breathing and when sterile insertion feasible |
| SQ hydration | Stable mild dehydration—not IO’s role |
Scenario
A 56-year-old in septic shock has three failed PIV attempts; BP is falling; antibiotics and fluids are ordered now. A trained provider places right proximal humeral IO, confirms flush without soft-tissue swelling, gives protocol IO lidocaine because the patient is still conscious and grimacing with flush, starts resuscitation fluids and antibiotics, and simultaneously prepares for ultrasound PIV or central line. Within two hours a triple-lumen CVC is placed and verified; the IO is removed and the site dressed. This sequence—bridge, treat, replace, remove—is the exam ideal.
High-yield exam traps
- Treating IO as long-term access comparable to a PICC
- Placing IO in a fractured tibia or through cellulitis
- Second IO attempt in the same bone after first failure
- Forgetting infusion pain management in conscious patients
- Delaying removal beyond need when good IV/CVAD exists
- Confusing IO with intramuscular injection dosing mindset for all drugs without checking emergency IV/IO equivalence rules
What is the primary role of intraosseous access in acute care?
Which condition is a contraindication to placing an intraosseous needle in a specific bone?
A conscious adult reports severe pain as IO fluids are pressurized. Assuming time and hemodynamics allow protocol steps, which intervention best addresses marrow infusion pain?
After successful resuscitation, a stable ICU patient has a newly placed, functioning multi-lumen central line. The humeral IO was inserted three hours earlier and is no longer needed. What is the best action?