A midline catheter is a specialized, long intravenous tube inserted into a vein, typically in the upper arm, with its tip positioned at or below the armpit. This device is commonly used for delivering extended courses of fluids or medications, such as long-term antibiotics, which might otherwise damage smaller peripheral veins. The dressing covering the insertion site prevents bacteria on the skin from entering the bloodstream. Maintaining this sterile barrier through safe and timely dressing changes is essential for preventing infection.
Necessary Supplies and Environment Preparation
A sterile dressing change relies on meticulous preparation, beginning with assembling a specialized kit. A standard sterile kit typically includes a chlorhexidine gluconate (CHG) antiseptic swab or applicator, a transparent semipermeable membrane (TSM) dressing, a sterile securement device, two pairs of gloves (one clean, one sterile), a surgical mask, and sterile tape. Before opening any supplies, the caregiver must perform thorough hand hygiene using soap and water or an alcohol-based hand sanitizer.
The environment itself requires careful management to reduce the risk of contamination during the procedure. Ensure the patient is positioned comfortably, and if possible, their head should be turned away from the catheter site to prevent breathing or coughing near the sterile field. Any surfaces used for the supplies, such as a bedside table, should be cleaned and dried before the sterile kit is opened. Both the person performing the dressing change and the patient, if tolerated, should wear a mask to prevent airborne bacteria from settling on the exposed insertion site.
A new catheter securement device must be ready, as the existing one should be replaced with every dressing change. Transparent dressings must be replaced a minimum of every seven days, or immediately if the dressing becomes wet, soiled, or begins to lift off the skin.
Step-by-Step Dressing Replacement
The dressing change procedure begins by carefully removing the old dressing, a step that requires stabilizing the catheter with one hand to prevent accidental dislodgement. Use a clean pair of non-sterile gloves for this initial step, peeling the old dressing off slowly, moving toward the insertion site while supporting the catheter. Once the old dressing and securement device are removed, these contaminated materials must be immediately discarded into a designated biohazard receptacle.
After removing the non-sterile gloves and performing another round of hand hygiene, the site must be inspected for signs of complications. Look for any localized redness, swelling, or unusual drainage at the point where the catheter enters the skin, and visually assess the length of the external tubing to confirm the catheter has not migrated. This brief assessment is performed just before donning the sterile gloves, which marks the beginning of the strictly sterile portion of the procedure.
The skin cleansing process utilizes the CHG applicator. The antiseptic solution must be applied with a firm, back-and-forth friction scrub over the insertion site and the surrounding skin for at least 30 seconds. This scrubbing motion helps to lift and inactivate microorganisms, preparing the skin for the new sterile barrier.
Allow the antiseptic to air dry completely, which typically takes 30 to 60 seconds; do not speed up this drying process by fanning or wiping. The CHG’s antimicrobial action continues as it dries, forming a protective layer on the skin. Once the site is fully dry, apply the new securement device to anchor the catheter tubing to the skin, preventing movement that could cause irritation or infection.
Next is the application of the transparent dressing, which provides the sterile seal and allows for continuous visual inspection of the insertion site. The dressing should be centered over the insertion point, ensuring the entire securement device and the catheter hub are covered and the edges are sealed tautly against the skin. Write the date and time of the change, along with the caregiver’s initials, directly onto the dressing’s label.
Site Vigilance and Emergency Indicators
After the dressing change, monitor the insertion site and the patient’s overall condition. The transparent dressing allows for daily inspection of the skin around the catheter for localized signs of infection. Look for changes such as increasing redness, warmth, or swelling near the insertion site, or any pain that persists or worsens. The presence of purulent, yellow, or green drainage from the exit site requires immediate contact with a medical professional.
Beyond local symptoms, watch for systemic indicators that suggest a bloodstream infection. A sudden onset of fever, shivering, or unexplained chills indicates the infection may have spread throughout the body. Other severe signs requiring emergency medical attention include excessive bleeding that saturates the dressing, noticeable displacement of the catheter, or the development of pain or swelling in the entire arm, which may indicate a blood clot.
Do not attempt to push the catheter back in if it has partially or fully been pulled out, and do not use scissors or sharp objects near the catheter to adjust the dressing. If any of these emergency indicators are observed, or if the dressing becomes loose, wet, or damaged, the healthcare team or physician should be notified at once.