A Peripherally Inserted Central Catheter (PICC line) is used to deliver treatments directly into a large vein near the heart. The catheter is inserted into a peripheral vein, typically in the upper arm, and threaded until the tip rests in the superior vena cava, a major vein just above the right side of the heart. This central placement allows for the rapid dilution of medications and fluids, making it suitable for long-term therapies like chemotherapy or extended antibiotic courses. Drawing blood from a PICC line is a specialized procedure performed exclusively by trained healthcare professionals using strict aseptic technique.
Why Blood Draws Utilize a PICC Line
The choice to draw blood from a PICC line is often based on the need to preserve a patient’s peripheral veins. Patients requiring frequent blood sampling can experience significant damage to their peripheral veins from repeated venipuncture. Utilizing the PICC line eliminates the need for needle sticks, which reduces patient discomfort and the potential for hematomas.
The location of the PICC line tip in the central circulation provides a reliable source for high-quality blood samples. For certain laboratory tests, obtaining a sample directly from the central bloodstream can be preferable to a peripheral sample. This method also offers an efficient workflow, allowing for both the administration of necessary treatments and the collection of diagnostic samples through a single access point.
Preparation and Necessary Equipment
Drawing blood from a PICC line begins with meticulous preparation to ensure a sterile environment and prevent infection. The healthcare professional performs thorough hand hygiene and dons appropriate personal protective equipment, including clean gloves. Equipment is then gathered, including sterile gloves, antiseptic agents like chlorhexidine scrub wipes, and the required blood collection tubes.
Specific flush syringes filled with 0.9% sodium chloride (saline) are prepared, typically in 10 mL sizes. This size is important because it generates less pressure than smaller syringes, protecting the catheter wall from possible damage during the flushing process. A blood transfer device is also prepared to safely move the collected blood from the syringe into the vacuum-sealed collection tubes. Before connecting any equipment, the clinician must confirm the patient’s identity using two identifiers and explain the procedure.
The Step-by-Step Blood Drawing Process
The mechanical process of drawing blood from a PICC line prioritizes the maintenance of sterility at the catheter hub. First, the existing protective cap is removed, and the needleless connector (hub) is vigorously scrubbed with an approved antiseptic agent for the required contact time, and then allowed to dry completely. This scrubbing action is essential for physically removing contaminants from the connection port.
Once the hub is disinfected, a sterile, empty syringe, designated as the “waste” syringe, is attached. The clinician slowly aspirates a volume of blood, typically 5 to 10 mL, which is then discarded. This initial waste volume is necessary to clear the catheter of any residual flushing solution or medication that was infusing, which could otherwise dilute or contaminate the lab sample and lead to inaccurate test results.
After the waste blood is collected and the syringe is disconnected, the hub is scrubbed again to maintain a clean access point. The sample syringe or a vacuum collection system is then attached, and the required volume of blood is gently withdrawn. Aspiration must be performed slowly to prevent the catheter from collapsing, a phenomenon known as “catheter pinch-off,” which can damage the blood cells and potentially cause a faulty lab result.
Once the necessary sample is obtained, the collection syringe is removed, and the hub is scrubbed one last time. A 10 mL syringe pre-filled with saline is connected to flush the catheter, restoring patency and cleaning the inner lumen. The flush is administered using a “push-pause” technique, which creates turbulence inside the catheter to effectively dislodge any material adhering to the wall. The final step is to clamp the line while injecting the last 0.5 to 1 mL of saline, maintaining positive pressure, which prevents blood from flowing back into the catheter tip and causing a clot.
Safety Protocols and Potential Complications
The primary safety concern with any central line procedure is the prevention of Central Line-Associated Bloodstream Infection (CLABSI). Healthcare facilities implement a “central line bundle” of evidence-based practices to mitigate this risk. This includes strict adherence to hand hygiene, using a chlorhexidine-based skin preparation, and employing maximum sterile barrier precautions during insertion and dressing changes. Every connection point must be meticulously disinfected before access to prevent the introduction of bacteria into the patient’s central circulation.
Another significant risk is catheter occlusion, or clotting, which can prevent the line from being used for blood draws or medication administration. This is prevented by ensuring the line is consistently flushed with saline after every use, and by maintaining positive pressure when the line is locked. The procedure also carries a risk of air embolism, where air enters the bloodstream and travels to the heart. This is avoided by ensuring all connections are securely tightened and by clamping the line before disconnecting any syringe or infusion.