Vascular Access in Pediatrics

In a sick child, vascular access is often the slowest step in resuscitation. Get a route now, one that moves drugs and fluid. The better line can come later, once the child is stable. Shock and cold collapse small peripheral veins. That's why the intraosseous (IO) route is the fallback. It does not rely on them.

Why Kids Are Different

• Small, hard-to-find veins: low volume, cold and vasoconstriction all shrink peripheral veins, sometimes until none can be found.
• A non-collapsible route: marrow behaves like a big vein that can't collapse, so IO flow holds even when peripheral veins fail (manufacturer data).
• Neonatal anatomy: the umbilical vein and arteries are the neonatal routes. Where the tip sits is a safety issue.
• Same dose, different route: drugs and fluids given IO use the same dose, rate and concentration as IV. Calculate the weight-based dose as usual, and that's the dose you give.

Indications

• Cardiac arrest or shock when IV access is not rapidly available
• Failed peripheral IV attempts that reach the local limit (protocols commonly use 2 attempts or 90 seconds)
• Drugs or fluids that cannot wait for an IV
• Newborn needing emergency vascular access when IV access is not successful or not feasible: IO can be useful (2025 AHA Guidelines for CPR and ECC, Part 5, COR 2a, LOE C-LD). The umbilical vein remains the preferred route

Contraindications

• Absolute: fracture of the target bone (fluid leaks through the break), and infection or burn at the insertion site
• Use another site: an IO attempt in the same bone within the previous 48 hours, orthopedic surgery or a prosthesis at the site, excess tissue that hides the landmarks, or a landmark that cannot be identified (manufacturer pediatric sheet)

Set the Attempt Limit Before the Call

Set the failed-IV limit before the call, and follow your protocol. Don't keep chasing an IV while a drug waits. How many attempts or seconds you get depends on the protocol.

The 2025 AHA Guidelines for CPR and ECC want fast access for drugs in pediatric cardiac arrest. Start it fast, by IV or IO (Part 8, Recommendation 7.1, COR 1, LOE C-LD). Pick between them by availability, expertise and timeliness (COR 1, LOE C-EO). Here's what people miss: the guideline sets no attempt count.

Pink is the usual choice under 40 kg. The manufacturer's pediatric sheet puts pink at 3–39 kg and blue at 3 kg and up. Blue comes out only when local protocol or tissue depth calls for it. Yellow is the 45 mm needle for 40 kg and up, or for excess tissue depth. Those cut-offs are set by local protocol.

Kit

• EZ-IO power driver and needle set
• EZ-Stabilizer dressing and EZ-Connect extension set (priming volume about 1.0 mL)
• Saline flush: 2–5 mL for an infant or child; 5–10 mL for an adult
• Preservative-free and epinephrine-free lidocaine 2% for an awake patient, per protocol (review the lidocaine cautions and contraindications)
• Pressure bag or infusion pump, tubing and a stopcock

A peripheral IV is the first choice, as long as it goes in quickly. Hit your attempt limit, then move to IO. Don't keep extending the attempts.

Common Sites

1. Choose the vein: pick a visible or palpable vein that is straight and stable.
2. Improve the view: warm the limb, use transillumination in infants, lower the limb below heart level, or apply a tourniquet (in neonates, an assistant's finger can serve).
3. Insert and anchor: advance the catheter, then secure it so it cannot move.
4. Confirm: look for blood return and a flush that runs without swelling.
5. Stop at the limit: after your attempt limit, place an IO.

Size up as far as the vein safely allows, per local protocol. Landmark attempts failing? Use ultrasound guidance if your program has it. Still delayed? Follow protocol for non-vascular routes such as intramuscular or intranasal medications.

An IO needle goes into the marrow cavity of a long bone. The manufacturer calls the marrow a non-collapsible venous space. Most drugs and fluids given IV can go IO at the same dose, rate and concentration. Verify flow before every infusion.

IO Sites

Insertion Steps

1. Prime: confirm the lidocaine dose per protocol. The extension set holds about 1.0 mL, so for small pediatric doses (a 10 kg child's 0.5 mg/kg dose is 0.25 mL), attach the syringe directly to the needle hub and prime the set with saline. Prime with lidocaine only when the dose volume matches the priming volume.
2. Position and clean: stabilize the limb and clean the site per protocol. For the distal femur, keep the leg straight.
3. Set the needle: aim at 90° to the centre of the bone and press gently until the tip touches bone.
4. Check the 5 mm mark: the 5 mm black mark must be visible above the skin before you drill.
5. Drill: squeeze the trigger and apply gentle, steady pressure until the hub seats. If the driver fails, advance by hand with a twisting motion.
6. Stabilize and dress: remove the driver and stylet, apply the EZ-Stabilizer dressing, and attach the extension set (primed as in step 1) with the clamp open.
7. Flush: flush with 2–5 mL saline for a child. It must run without resistance or swelling.
8. Document: record the time, site, needle length, flush result and any pain.

In a neonate, the umbilical vein is the fast route for drugs and fluid. Trained staff place it. The 2025 AHA Guidelines for CPR and ECC, Part 5, recommend umbilical vein catheterization for newborns who need emergency vascular access (COR 1, LOE C-LD). When intravenous access fails or isn't feasible, IO can be useful (COR 2a, LOE C-LD).

Anatomy

The cord usually holds one large, thin-walled vein and two smaller, thick-walled arteries. The vein is the one you catheterize.

Insertion Length

A formula gives you a starting length, nothing more. The UAC formula above is for the high position. A low UAC (L3–L5) needs a different length. Confirm the tip position by X-ray or ultrasound.

Target Tip Positions

Emergency Placement in Resuscitation

In an emergency, advance the catheter only until blood returns freely. That shallow, low-lying spot limits how much drug reaches the liver and portal system. Once the baby is stable and needs ongoing central access, reposition or replace the catheter to the measured, imaging-confirmed position below.

Insertion Steps

1. Prepare: trim the cord to a short stump, secure it with a tie, and prepare a sterile field.
2. Identify: find the single thin-walled vein (usually at about 12 o'clock) and the two arteries.
3. Measure: calculate the insertion length before you start, and add the stump length.
4. Insert gently: pre-flush the catheter, then advance toward the head to the calculated length. In an emergency, advance only until blood returns freely.
5. Confirm: check blood return and a free flush, then confirm the tip on X-ray or ultrasound.
6. Reposition and secure: adjust the depth if the tip is high or low, then secure the catheter.

Trained teams usually place central lines when peripheral and IO routes are not enough, or when the child needs a line for longer therapy. The 2022 SHEA CLABSI update, written for acute-care hospitals, covers adults and children. It recommends ultrasound guidance for catheter insertion. Every insertion gets maximal sterile barrier precautions. For older infants and children, chlorhexidine-alcohol is the usual skin prep. In preterm infants and infants under 2 months, use chlorhexidine with caution, since its label warns of irritation or chemical burns. Follow local neonatal policy, and remove excess prep after the procedure.

1. Confirm the need: place a central line only when the access problem and the therapy justify it.
2. Prepare the field: use maximal sterile barrier precautions and the skin prep chosen for the child's age, as described above.
3. Insert with ultrasound: visualize the vein and needle, and limit passes.
4. Confirm: check blood return, flush, and confirm the tip position by imaging.
5. Remove when no longer needed: remove nonessential catheters promptly.

Signs of Correct Placement

• IO: the needle stands stable, and saline flushes without resistance or swelling. Blood on aspiration backs up placement. No blood does not mean failure.
• UVC: free blood return and a tip in the target zone on X-ray or ultrasound.
• Peripheral IV: blood return and a flush that runs without swelling.

Neonates and Young Infants

• Only trained staff place a UVC. Neonatal drug doses differ from child doses, so use the neonatal doses in the table above.
• Neonatal epinephrine is given at 0.01–0.03 mg/kg IV/IO; check the tip of every umbilical catheter before use.
• Scalp veins have no valves, so shine a light underneath to see them.

Adolescents and Larger Children

• Use adult needle sizes and sites at 40 kg or more, or per your protocol.
• Switch to adult drug doses only when your protocol's switch rule applies.

Obesity and Excess Tissue

• Excess soft tissue hides the landmarks. Reach for the longer 45 mm needle, or choose another site.
• Choose the dosing weight by your weight hierarchy (see the weight-based dosing page).

Children With Existing Devices

• Note any existing IO, central line or port, and its site and date, before placing a new device.

• Prepare lidocaine and saline flushes before the attempt, labelled and drawn to the dose.
• Secure the needle set with the dressing, and check the site and limb at every move.
• Infuse under pressure with a pressure bag or pump for fluids and drugs.
• Keep an infant warm during the procedure and transport.
• Hand off the line type, site, time placed and everything infused.
• Flag any IO in place for MRI: no MRI with an IO in place.
• Keep a humerus IO arm below 90 degrees of abduction and minimize movement; keep a distal femur IO leg extended and stabilized.