Her literature research uncovered the idea of midline catheter use in adults, but there were no studies in children. Casacchia set out to change that — and her study’s results ultimately proved that this novel access method for pediatrics was not only a viable option, but in many cases, a better one.
In short, she says, “It’s completely changed our approach.”
Breaking down the challenge
Central lines provide good vascular access, but can come with the risk of infection, bleeding, thrombosis, and pneumothorax. Plus, pediatric patients often require a central line, which typically means surgery under general anesthesia, adding to the risk.
Superficial peripheral intravenous (PIV) access presents fewer risks than central lines. But it presents other challenges in pediatrics. In Casacchia’s experience, that includes infiltrations, strict mobility limits, multiple venipunctures, and flow rate issues, especially during long procedures. Patients may need a second procedure to achieve the collection goal. And multiple attempts at PIV access can damage blood vessels — a major problem for patients who need long-term intravenous therapy.
Casacchia dove into research for ideas for improvement in care, finding a few older, adult-based articles in which midlines were used for apheresis. “More current data was difficult to find, but my curiosity was piqued,” she says. Soon after, Casacchia noticed an ICU nurse placing a midline catheter. “It was a long catheter, small in diameter, and the nurse was inserting it by ultrasound in the upper arm,” she recalls. “I began to ask questions regarding its ability to be used in apheresis, especially in children.”
Testing the theory
When Casacchia found that there were no studies about the use of midlines in children, she decided to start her own. With buy-in from the CHOC medical director, she built a partnership between the apheresis and vascular access teams, then recruited one of her apheresis nurses as a test subject.
The midline catheter insertion went well and, during a 90-minute procedure, says Casacchia, “We learned that the basilic vein worked better with access flow than the cephalic vein, and the cephalic vein worked well with the return flow rate.”
They had the collected mononuclear cell collection (MNC) product sample tested. “Results showed 100% viability and sterility, with cells looking healthy and intact,” says Casacchia.
Conducting the study
This gave Casacchia and her team the green light to launch a retrospective observational study to evaluate the safety and efficacy of midline catheters in pediatric apheresis. The study ran from March 2018 through August 2020, evaluating 100 midline catheters placed during 73 apheresis procedures.1 All procedures used the Spectra Optia® Apheresis System from Terumo Blood and Cell Technologies and were performed by an experienced, board-certified vascular access nurse with specialized training in the use of ultrasound.
The first patients to participate were a pair of teenage siblings donating stem cells. Casacchia recalls her excitement seeing the teens freely moving their arms and using their smartphones, without the mobility restrictions typical with superficial PIV.
Patient highlights
Shining a light on the results
Study results were convincing, showing that midline catheters are a safe, effective option for pediatric apheresis.
Inlet flow rates met or exceeded recommended rates for apheresis in children and adults, and clinical goals were met for post-procedure fraction of cells remaining (FCR) percent, hematocrit (Hct) percent, hemoglobin S (HgbS) percent, and CD34+ cell counts. No adverse events occurred.
The study also demonstrated that midline catheters may improve and help preserve access to the vein, may create time efficiencies, and may result in fewer flow-based alarms on Spectra Optia.
Pain, mobility, and satisfaction assessments were likewise encouraging, showing that midlines can improve the patient and donor experience. (See charts below.)
Tips and barriers
After five years of using midline catheters for pediatric apheresis procedures, Casacchia has identified some helpful tips for those interested in trying the approach:
- Prepare the patient. Schedule a pre-procedure appointment to introduce the patient to the team, explain the procedure, and use the ultrasound to show patients their veins. On procedure day, the patient should be well hydrated and nourished, with warm packs placed on arms. Remember that a full bladder can affect midline performance.
- Make advance decisions. Before the procedure, the team must select the appropriate vein, insertion technique, and catheter diameter size and length.
- Position properly. Pay attention to arm position and tourniquet placement during the procedure. Keep the warm packs in place and assess mobility limits on the inlet arm.
- Keep calm. Anxiety can cause veins to constrict. A soothing environment and anxiolytics as needed can help keep the patient relaxed. Involving a child life therapist or fun distractions such as toys, movies, and music may also help.
Of course, as with any procedure, it’s important to consider potential barriers, as well. Casacchia suggests professionals keep in mind that:
- Not all patients have veins that can accommodate the midline.
- Studies have not been conducted on patients younger than 9 years old.
- Using midline catheters typically requires an ultrasound device and additional training for deep vein placement.
Moving forward
Today, says Casacchia, “100% of our monthly routine red blood cell exchanges (RBCX) and more than 60% of our hematopoietic progenitor cell apheresis (HPCA) and continuous mononuclear collection (CMNC) apheresis procedures are performed using midlines for peripheral access.”
Casacchia and her team continue to study the use of midline catheters in younger and smaller patients. As of summer 2023, they have conducted more than 260 procedures, placing midlines in patients as young as 9 years old and as small as 23 kg.
1 Casacchia C, et al. Novel use of a midline catheter for therapeutic and donor apheresis in children and adults. J Clin Apher. 2021;36(5):711-718.