WALL REF 03 · FIELD REFERENCE

IV / IO Access

Sites, gauges, flow — and the marrow when veins fail
✚ CRASH CARD
crashcard.co
18 × 24 IN · WALL REFERENCE
GoldFlow / rate — bigger & faster
OliveVeins & anatomy — access technique
RustDanger · contraindications · infiltration
1Gauge × Flowbigger bore =
more flow
0 150 330 mL/min 14G orange 330 16G grey 215 18G green 105 20G pink 65 22G blue 36 24G yellow 22
≈ gravity, saline. A pressure bag or a shorter catheter raises every number; length & viscosity drop it. Chips are the ISO 10555-5 color code.
GGauge for the Jobmatch bore
to the task
GAUGEISOUSE IT FOR
14–16Gorg / greyTrauma, massive transfusion, rapid volume, OR.
18GgreenAdults, blood products, CT contrast — the ED workhorse.
20GpinkStandard maintenance, the stable ward patient.
22GblueFragile / elderly veins, difficult access.
24GyellowNeonates, peds, tiny fragile veins.

Blood: 20G+ runs freely. Best gauge = biggest that fits and lasts.

QWhy Bore WinsPoiseuille
Q ∝ r4 ÷ L

Flow scales with the radius to the FOURTH power and falls with length. Double the bore → 16× the flow.

Short + wide wins. One 14G (~330) out-flows two 20G (~130 total). A short peripheral beats a long central line for volume — a triple-lumen's long, narrow lumens are slow.

▹Anatomy of the Stickcatheter over needle
SKIN VEIN FLASHBACK = in the lumen bevel up thread the catheter, not the needle
  1. 1Anchor — pull the skin taut distal to the site.
  2. 2Bevel up, 10–30° — drop nearly flat on flashback.
  3. 3Advance 1–2 mm more, then thread the catheter off the needle.
  4. 4Release, withdraw, flush — tourniquet off, cap, secure & date.
2Difficult Accessclimb in order
  1. 1Optimize peripheral — tourniquet, warmth, dependent position, gravity, hydrate, small distal vein, surface ultrasound. Tap, don't slap.
  2. 2Ultrasound-guided — deep forearm / basilic with a longer catheter. Skill + probe when the surface is dry.
  3. 3External jugular — big-bore last-resort peripheral: head-down, hold skin traction, one clean pass.
  4. 4IO — go early in a true emergency. Don't grind on veins while a patient codes; drill, resuscitate, convert later.
  5. 5Central line — trained provider, when time & indication allow. Not the fastest route to volume.
3The Peripheral Mapwhere the veins live
· best-for · pearl
DORSUM → SHOULDER — PICK BY THE JOB olive = vein · dot = target
UPPER ARM FOREARM BASILIC deep · medial upper arm Ultrasound-guided when surface veins fail. ⚠ brachial artery & median nerve run alongside. ANTECUBITAL · AC median cubital / elbow crease Big & fast — resus & CT contrast. Elbow flexion occludes it — poor for a long dwell. DORSAL HAND metacarpal network Fine for the stable patient. Small & visible; avoid if you need volume or pressors. CEPHALIC lateral forearm Durable & comfortable — the best midline target for the admitted patient. EXTERNAL JUGULAR Big-bore last-resort peripheral. Head-down, hold traction, one clean pass.
Confirm placement

Flashback, then flush freely with no bleb. Blood return, no swelling, no pain, no leak at the hub. Secure & date it.

Match line to mission

Volume / codes → short, wide, proximal (AC). Dwell / infusions → cephalic forearm. Long-term pressors → central.

Sites to avoid pick another vein
  • Lower-limb veins in adults — DVT / infection; a bridge, not a home.
  • The AV fistula / graft arm — never. Save that circuit.
  • Mastectomy / axillary-dissection side; the weak (stroke) limb.
  • Distal to a fresh blown stick in the same vein — it leaks.
  • Over a flexion crease for a dwell; hard, sclerosed, cord-like veins.
Secure · date · watch

Transparent dressing, loop the tubing, label date / time / gauge. Flush 10 mL saline in a turbulent push-pause; saline-lock stable lines. Reassess every shift — pull it the moment it turns red, swollen, or painful and resite rather than force a bad line.

IV vs IO — at a glance
 IVIO
PlaceMinutes — if a vein cooperates.Seconds — drill & go.
FlowHigh with a big bore.Lower — wants a pressure bag.
PainMild stick.Flush burns — lido first if awake.
DwellHours to days.~24 h, then convert.
DrugsEverything.Everything — same doses.
4IO Landmarkswhen veins fail,
drill the bone
KNEE med. malleolus PROXIMAL TIBIA ≈2 cm below & ~1 cm medial to the tuberosity, on the flat medial face. DISTAL TIBIA ≈3 cm above the medial malleolus. Easy in adults. SHOULDER arm adducted PROXIMAL HUMERUS Greater tubercle. Hand on belly, arm internally rotated. Highest flow — closest to core. Peds also: distal femur. Needle length by weight/tissue — see a 5-mm mark past the hub.
5IO Flow & Lidocainepush it in

IO is slower than the same-gauge IV — marrow resists. A pressure bag (~300 mmHg) or a push-pull syringe is usually needed for real volume. Give a firm 10-mL saline flush first to open the space.

Awake patient? Preservative-free 2% lidocaine ~20–40 mg (0.5 mg/kg, max ~40 mg adult) slow IO over ~2 min before the flush — the flush is what hurts. Dose per device IFU / local protocol.

▸ Anything you can give IV, you can give IO.

✕Don't Drill HereIO contraindications
  • Fracture of the target bone — fluid leaks out the break.
  • Prior IO / attempt in that same bone < 24–48 h.
  • Prosthesis or hardware at the site.
  • Infection or burn over the insertion skin.
  • Can't find landmarks — obesity, edema, distortion.
  • Osteogenesis imperfecta / severe bone disease.
6Worked Casesreal numbers
Trauma resus — volume now2× AC
Hypotensive bleed, needs blood fast. Two short 16–18G in the AC (~215 + ~105 ≈ 320 mL/min) → out-flow one long triple-lumen central line. Short + wide + two of them, on a rapid infuser / pressure bags.
Three failed sticks, crashingGo IO
peri-arrest · 3 blown attempts · no US win Stop grinding on veins. Drill a proximal humerus (highest flow) → push drugs & fluids now. Time is the enemy — convert to definitive access after ROSC.
Awake patient needs IOLido first
Conscious, in pain, but access is critical. Confirm placement → preservative-free 2% lidocaine ~40 mg slow IO → wait ~1 min → then flush & run. Skip the lido and the flush makes them scream.
!Line Faultssign → action
FAULTSIGNDO
InfiltrationCool, taut, swollen; flow slows.Stop, remove, elevate.
ExtravasationAbove + a vesicant — blister/necrosis risk.Stop, aspirate, antidote per protocol.
PhlebitisRed, warm, tender cord along the vein.Remove, warm compress, resite.
OcclusionWon't flush; positional.Reposition, gentle flush; replace.
DislodgedLeaking hub, no return.Resecure or replace.
REMEMBER — Short + wide = fast · Distal before proximal · When veins fail, drill · Anything IV goes IO. IO is time-limited (~24 h) — convert.
Sheet
IV / IO Access
Series / No.
WALL REF 03
Part No.
CC-WR-03
Rev
B
Status
FIELD REFERENCE — NOT A PROTOCOL. VERIFY LOCALLY.

SOURCES: Teleflex Arrow EZ-IO IFU & clinical resources (site ID, flow, lidocaine comfort protocol) · BD catheter flow specs & ISO 10555-5 color code · AHA ACLS/PALS (IO access) · Roberts & Hedges, Clinical Procedures in Emergency Medicine · Marino, The ICU Book. Flow ≈ gravity/saline — verify against device & local protocol. © 2026 Claustrum LLC d/b/a Crash Card · crashcard.co · Printed in Minnesota.