A peripheral intravenous (PIV) line is a thin, flexible tube, known as a catheter, that healthcare professionals insert into a small vein, typically in the arm or hand. This common procedure provides a direct pathway into the bloodstream for the delivery of fluids and medications. Proper verification of the catheter’s position is essential to ensure correct treatment delivery and prevent serious complications. Confirmation involves several checks following the initial insertion.
The Role of Blood Return
Observing blood return, often called “flashback,” is the first visual confirmation that the insertion needle has successfully punctured the vein. As the needle enters the vein, blood pressure pushes a small amount back into the clear chamber of the catheter device. This physiological phenomenon is a result of the pressure gradient between the vein and the outside environment. Seeing this flashback is an expected sign during the insertion process.
While blood return indicates successful venipuncture, it does not confirm the final, correct placement of the entire catheter. The needle is slightly longer than the flexible catheter tube. Flashback may occur while the needle tip is in the vein but before the plastic catheter is fully advanced. Therefore, relying only on this initial sign is insufficient for confirming the PIV’s readiness for use.
Verifying Placement: The Definitive Step
The most reliable method for confirming the PIV’s correct placement and function is performing a patency check, commonly referred to as flushing. This procedure involves administering a small, controlled volume of sterile normal saline solution directly through the catheter. A healthcare provider typically injects the solution using a pulsatile method to clear the line and check for resistance. This active confirmation is distinct from the passive observation of blood return.
A successful flush confirms that the catheter tip is fully seated within the vein lumen and the vessel is patent. During flushing, the patient should not report pain or discomfort, and the fluid must flow freely without resistance. Definitive signs of correct placement include the absence of visible or palpable changes around the insertion site.
A failed patency check reveals signs of infiltration or extravasation, meaning the fluid is leaking into the surrounding tissue. Signs of failure include the patient experiencing pain or a burning sensation, or the clinician observing immediate swelling, blanching, or coolness of the skin around the catheter tip. If these signs appear, the catheter must be immediately removed to prevent further tissue damage.
Troubleshooting Absent Blood Return
Causes of Absent Blood Return
A PIV may be correctly placed and functional even if no blood return is observed when attempting aspiration. A lack of blood return can be caused by the catheter tip resting against the inner wall or a valve within the vein, physically blocking the lumen. Patient factors, such as dehydration or hypovolemia, can result in low venous pressure insufficient to push blood back into the catheter. Additionally, a very small catheter gauge can make it difficult to aspirate blood without the vein wall collapsing.
Actionable Steps
If blood return is absent, steps can be taken before determining the PIV is unusable. These include gently rotating the catheter a few degrees or having the patient slightly reposition their limb. This may move the catheter tip away from the vein wall or valve.
If these maneuvers fail, the definitive step is to attempt the patency check by flushing with normal saline, using extra caution. If the saline flushes without resistance and the patient reports no discomfort or swelling, the PIV can be used but should be monitored more frequently. If the flush meets resistance or causes pain, the line must be considered infiltrated and removed immediately.