In peripheral vein cannulation, a plastic catheter (cannula) is inserted into a peripheral vein, typically using a catheter-over-needle device.
Peripheral vein cannulation is the most common method of obtaining vascular access and may be done by many members of the health care team.
Ultrasonographic guidance, when equipment and trained personnel are available, can facilitate peripheral vein cannulation, especially of deep, nonpalpable veins.
(See also How To Do Peripheral Vein Cannulation—Ultrasound Guided.)
Indications for Peripheral Vein Cannulation
Administration of IV fluids and drugs
Repetitive venous blood sampling
Contraindications to Peripheral Vein Cannulation
Absolute contraindications
None
Relative contraindications
Planned use of very concentrated or irritating IV fluids: Use a central venous catheter or intraosseous infusion
Infection or burned skin at a prospective cannulation site
Injured or massively edematous extremity
Thrombotic or phlebitic vein
Ipsilateral mastectomy or lymph node dissection
In the above situations, use another site (eg, the opposite arm).
Complications of Peripheral Vein Cannulation
Complications are uncommon and include
Local infection
Venous thrombophlebitis
The above complications can be reduced by using sterile technique during insertion and by replacing or removing the catheters within 72 hours.
Other complications include
Extravasation of infused fluids into surrounding tissues
Arterial puncture
Hematoma or bleeding
Damage to the vein
Nerve damage
Catheter embolism
Equipment for Peripheral Vein Cannulation
Nonsterile gloves
Tourniquet, single-use
IV catheter, typically 18- or 20-gauge for routine infusions in adults (14- or 16-gauge for high-volume infusion) and 22- or 24-gauge in infants and small children
IV infusion set (eg, IV solution bag, hanger, tubing) or saline lock
Dressing materials (eg, tape, gauze, scissors, transparent occlusive dressing)
Optional equipment includes
Vein-finder device (eg, infrared vein viewer, ultrasonography device)
Immobilization board and stockinette, for use if catheter is inserted over a joint
Additional Considerations for Peripheral Vein Cannulation
Latex hypersensitivity: Use latex-free gloves and tourniquet.
A sterile field is usually not needed for peripheral venous cannulation. However, sterile (ie, aseptic or aseptic no-touch) technique should be followed.
Peripheral IV catheters should not overlie a joint (eg, the antecubital fossa) unless other sites are unavailable—joint motion will kink the catheter and also is uncomfortable. If such a site must be used, an immobilization board can help prevent the joint from flexing.
Relevant Anatomy for Peripheral Vein Cannulation
Peripheral veins are most easily cannulated in a straight segment proximal to the junction of 2 tributaries.
A tortuous vein segment may be difficult to cannulate, and venous valves also may impede catheter insertion.
In general, cannulate more distal veins first; more proximal sites are used as the distal sites are expended.
Upper extremity cannulation sites are the most durable and convenient and are less likely to have complications such as thrombophlebitis. Therefore, use lower extremity veins or external jugular veins only if suitable upper extremity veins are unavailable.
Positioning for Peripheral Vein Cannulation
Rest the body part being cannulated on a comfortable surface and adjust the position to optimally expose the site.
For the external jugular vein, place the patient in Trendelenburg position with the head tilted slightly contralaterally.
Step-by-Step Description of Peripheral Vein Cannulation
Identify and prepare the site
Do a preliminary inspection (nonsterile) to identify a suitable vein: Apply a tourniquet, have the patient make a fist, and palpate using your index finger to locate a large-diameter vein that is nonmobile and has good turgor.
To help distend and locate veins, tap a potential site with your fingertips. It may help to allow the arm to hang down, increasing venous pressure, and/or apply a warm compress. Use a vein-finder device if a suitable vein is not readily seen or palpated.
After identifying a suitable cannulation site, remove the tourniquet.
Apply topical anesthetic if it is being used, and allow adequate time for it to take effect (eg, 1 to 2 minutes for gas injector, 30 minutes for topical).
Prepare the IV infusion setup or the saline lock equipment.
Wear gloves.
Cleanse the skin site with antiseptic solution, beginning at the needle-insertion site and making several outwardly expanding circles.
Allow the antiseptic solution to dry completely.
Insert the peripheral venous catheter
Test the angiocatheter: Hold the hub of the cannula and slightly rotate the cannula about the needle to make sure it moves smoothly. Do not slide the needle in and out of the cannula.
Reapply the tourniquet.
Hold the area steady with your nondominant hand and use your thumb to apply gentle traction to the vein distal to needle-insertion site to prevent it from moving. Traction may not be necessary for larger veins in the forearm or antecubital fossa.
Hold the angiocatheter between the thumb and index finger of your dominant hand with the needle bevel facing up.
Tell the patient that the needlestick is about to happen.
Insert the needle in the skin at a shallow angle (10 to 30 degrees) about 1 to 2 cm distal to the point at which you intend to enter the vein.
Advance the angiocatheter into the vein using a slow, even motion. When the needle tip enters the lumen, blood will appear in the flash chamber of the angiocatheter (called a flash of blood), and you may feel a pop as the needle punctures the wall of the vein. Stop advancing the angiocatheter.
If no flash appears after 1 to 2 cm of insertion, withdraw the angiocatheter slowly. If it had initially passed completely through the vein, a flash may now appear as you withdraw the needle tip back into the lumen. If a flash still does not appear, withdraw the angiocatheter almost to the skin surface, change direction, and try again to advance it into the vein.
If rapid local swelling occurs, blood or fluid is extravasating. Terminate the procedure: Remove the tourniquet and the angiocatheter, and apply pressure to the puncture site with a gauze pad (a minute or 2 is usually adequate unless the patient has a coagulopathy). Choose a different site for any subsequent attempts.
Advance the catheter into the vein
Keeping the needle tip motionless within the lumen, carefully lower the angiocatheter to better align it with the vein, and advance it an additional 1 to 2 mm, to ensure that the tip of the plastic catheter also has entered the vein. This step is done because the needle tip slightly precedes the catheter tip.
Hold the needle steady and slide the entire length of the plastic catheter over the needle and into the vein. The catheter should slide easily and painlessly. Remove the needle.
If resistance or pain occurs, assume that the catheter is not in the vein. In most cases, you will need to stop the attempt and start over at a new site. Holding the catheter hub motionless, remove the needle and then slowly and gradually withdraw the catheter while watching the hub. If blood flows from the hub, stop withdrawing the catheter and try again to advance it. If no blood appears, continue to slowly withdraw the catheter. When the catheter has been removed, apply a dressing over the area with gentle pressure.
Occasionally, the catheter is in the lumen of the vein but cannot be advanced because it is pushing against a valve or a sharp turn in the vein. To help the catheter pass through a valve, advance the catheter while flushing it with fluid from a syringe or from the IV tubing. To help the catheter negotiate a tortuous vein, manually apply gentle distal traction to the vein to straighten it, and then try to advance the catheter.
Once the catheter is successfully placed, withdraw any blood needed for laboratory testing, remove the tourniquet, place some gauze underneath the hub, apply fingertip pressure to the skin proximal to the catheter tip (to compress the vein and limit blood loss from the hub), and connect the IV infusion or saline lock.
Begin the IV infusion/establish the saline lock
Attach the end of the IV tubing or the saline lock to the catheter hub.
Begin the infusion or flush the saline lock (inject about 5 mL of saline in rapid, small pulses). Fluid should flow freely.
If fluid extravasates or does not flow freely, remove the catheter, apply a dressing over the area with gentle pressure, and insert a new catheter at another site.
Dress the site
Wipe all blood and fluid from the site, being careful not to disturb the catheter.
Cover the catheter with a transparent occlusive dressing.
Loop the IV tubing (or saline lock tubing) and tape it to the skin away from the IV insertion site, to help prevent accidental traction on the tubing from dislodging the catheter.
Write the date and time of IV cannulation on the dressing.
Apply an immobilization board as necessary.
Aftercare for Peripheral Vein Cannulation
Replace or remove catheters within 72 hours of placement.
Warnings and Common Errors for Peripheral Vein Cannulation
Use only mild tension when applying the tourniquet; it is a venous, not an arterial, tourniquet.
If the vein is not entered, do not try to reposition the needle by moving the tip to one side or another; this can push the vein out of the way and also damage tissue. Instead, withdraw the needle almost to the skin surface before changing the angle and direction of insertion.
Never withdraw the catheter back over the needle or reinsert the needle into the catheter. Doing so could shear off the catheter tip within the patient.
If fluid does not flow freely, do not continue infusion attempts; this can cause extravasation and hematoma formation.
Tips and Tricks for Peripheral Vein Cannulation
Consider using double tourniquets (a second tourniquet is placed distal to the anticipated catheter-insertion site after placement of the first tourniquet) to engorge the veins for large body habitus or edematous limbs.
