Vascular access in resuscitation

Cannula sizes and flow

Poiseuille’s Law

• The flow of fluids through an IV catheter can be described by this
• Doubling the diameter increases the flow rate by 16 fold (radius ^ 4)
• The shorter the length, the greater the flow
• The greater the pressure, the greater the flow

Peripheral cannulation

• Areas to avoid
  • Lower limbs when pelvic/abdominal/thoracic trauma
  • Lower limbs have higher infection rate in general
  • Distal to complex injuries
  • Limb with an AV fistula
  • Lymphoedematous limbs or previous axillary clearance
  • Areas of phlebitis/cellulitis

Options for large-bore resuscitation

• 2 x large-bore peripheral IVC
• RIC line
  • Rapid infusion catheter
  • Seldinger technique with guidewire, short (6.5cm) and wide (8.5Fr) catheter that can be sutured in and dilator (catheter slides off this)
  • Requires 20G cannula or larger to be used to introduce guidewire
  • Carries risk of blowing vein and losing previously functional catheter
  • Short length precludes use in deeper veins i.e. femoral
  • Up to 600mL/min flow rate (without spring-loaded cannula hub)
  • Needle-free, spring-loaded hubs should NOT be used if attempting rapid infusions
• Intraosseous line (IO)
  • Humeral is first-line in adults; proximal tibia first-line in children
  • Firmly press needle through skin to the bone then squeeze trigger to screw into bone itself until resistance lost (medullary space entered)
  • Can use marrow aspirate for BSL and X-match and can give central drugs/products
  • Need pressure bag or pump to deliver fluids through IO (gravity alone is not enough)
  • Sizing
    • 15mm (pink) = Neonates and small children proximal tibia
    • 25mm (blue) = Children >40kg and adults proximal tibia and children at humerus
    • 45mm (yellow) = Adults at humerus
  • 45mm in adult humerus can deliver 150mL/min (21G peripheral IVC equivalent)
• Dialysis catheter
  • 2-lumen Dolphin allows flow rates of 200-400mL/min
  • Trialysis catheter provides a third lumen for drug/product/fluid administration, potentially with pressure-injection safety (Power-Trialysis)
• Sheath introducers
  • Aka Swann sheath
  • Long, very wide bore, single lumen catheters with a one-way valve at one end, through which triple-lumen central lines, Swann-Ganz catheters, pacing wires and coronary angiography catheters can be inserted
  • Allow simultaneous delivery of fluids via the side-catheter which runs perpendicular to the sheath and has a standard luer-lock connection (unlike the main hub)
  • Typically 8Fr used in resuscitation
  • Can be inserted into jugular or femoral veins (compressible) but may be limited in obese individuals as not as long as traditional CVL/dialysis catheters
  • Inserted via Seldinger technique with dilator pre-loaded inside the sheath
  • It is unclear what the flow rate achievable through the side port actually measures but no doubt it is high
• MAC line
  • Multi-lumen access catheters
  • Relatively short, 2-lumen central line
  • Has a sheath introducer built-in + 9Fr and 12Ga lines
  • Essentially the same as a sheath introducer with an additional 12Ga line

Last Updated on September 24, 2021 by Andrew Crofton