Peripheral venous cannulation, among the most common medical procedures, has revolutionized the practice of medicine. Peripheral intravenous (IV) catheters allow for the safe infusion of medications, hydration fluids, blood products, and nutritional supplements. 

• Vascular access should only be performed when there is an indication for use in the out-of-hospital environment. 
  • See → PR26: Venipuncture - Ethical decision making for more information.
• The need to obtain vascular access should be balanced against other acute clinical needs of the patient.  Conveyance of the patient must not be delayed in favor of establishing vascular access. 
• Catheter and site selection varies according to the patient's condition and intended use.

• Initiation of peripheral vascular access is contraindicated when appropriate therapy can be provided through a less invasive route (e.g., intramuscularly, intranasally, or orally).
• Paramedics must make informed decisions with respect to a patient’s need for vascular access, with consideration given to:
  • Current clinical status and stability.
  • Expected out-of-hospital interventions, such as the need to administer medications or fluid en route to hospital.
  • Anticipated in-hospital clinical course.  Note that a general expectation that the patient may require IV access at some point during their hospital stay is not, by itself, grounds to attempt IV cannulation.
• Intravenous devices can become dislodged or pulled out during patient movement.  Paramedics should consider the timing of patient movements when contemplating IV cannulation.
• Intraosseous access should be considered on critically ill or injured patients who cannot be successfully cannulated in a short period of time.
  • Higher flow rates have been reported when intraosseous needles are placed in the humeral head instead of the tibial plateau.  The humeral head is therefore the preferred site in cardiac arrest.

Hemorrhagic Shock