Australian nurse researchers say they have devised a simple method involving ultrasound to place intravenous catheters that will reduce the development of blood clots in cancer patients.
They investigated how the proportion of the vein measured at the insertion point taken up by an IV catheter – the catheter to vein ratio – affected rates of symptomatic venous thromboembolism in patients.
“The simple act of finding a vein of appropriate size before inserting the delivery device can make a difference”
They identified that a 45% catheter to vein ratio was the optimal cut-off with high sensitivity and specificity to reduce the risk of VTE.
Rebecca Sharp, a nursing lecturer from University of South Australia, said: “Clots form around the tubes that deliver drugs into patients’ veins, and can then break off to block blood supply to the lungs or cause other dangers to the patient’s health.
“My studies show that the simple act of finding a vein of appropriate size before inserting the delivery device can make a difference,” she said.
Ms Sharp used ultrasound to study vein size in 136 patients receiving hospital treatment for cancer.
She found the intravenous delivery device should occupy less than 45% of the selected vein width in order to reduce the risk of clotting. “Taking up more of the vein increases the risk of a blood clot by more than 10 times,” she said.
In addition, she said to get the 10-fold benefit takes only an extra six minutes to find a vein of the right size by ultrasound.
Her research involved peripherally inserted central catheters, which are inserted through a vein in the arm, and guided internally so the tip rests inside a large blood vessel just near the lungs.
“We call the PICC a ‘one stop shop’ for cancer therapies – once it’s in the right place, you can administer chemotherapy and other systemic treatments through that one vein,” noted Ms Sharp.
Nurse tests ultrasound to reduce clot risk in cancer patients
“It also provides a single access point to collect blood for the many tests that cancer patients often require,” she added.
When properly in place, the PICC reduces the level of trauma experienced by the cancer patient. However, when a blood clot forms at the insertion site, it creates not only an elevated immediate risk of death but also a much more complex medical journey.
“Often the PICC will be removed, and then the patient must undergoes months of extra treatment to remove the clot and prevent further clotting taking place,” she said. “It also creates a lot of initial extra pain and swelling.”
Related research showed that there is considerable variation in vein size across patients and that an infusion nurse can reliability measure vein diameter in the PICC clinic.
“All cancer patients should be assessed to find the right vein before chemotherapy commences,” said Ms Sharp.
Her findings have already made their way into the broader hospital setting, and are now part of the training provided to both nurses and doctors in main teaching hospitals in Adelaide.
Ms Sharp presented her research at Fresh Science South Australia 2015, a national programme that helps early-career researchers find and share their stories of discovery.
The results have also been published in the International Journal of Nursing Studies.