Preventing adverse events during paediatric cancer treatment: A multi-site hybrid randomised controlled trial of catheter lock solutions (The CLOCK trial)

Across Australia every year, children undergoing treatment for cancer experience more than 250 bloodstream infections, 70 deep vein thromboses, and 300 blockages - all caused from their central line. This central venous access device (CVAD) is vital as it administers treatments such as chemotherapy drugs and supportive therapies including blood transfusions and antibiotics, however we need to do more to prevent harm. When the CVAD is not in use, it is locked it with fluid. This fluid lock is an opportunity to prevent CVAD-associated complications. Therefore, the aim of this study is so compare the safety and effectiveness of the locking solutions KiteLock (Tetrasodium-EDTA (T-EDTA)) and heparinised saline with normal saline, which is routinely used in as part of standard care. Who is it for? You may be eligible for this study if you are aged younger than 18 years, have been diagnosed with an oncological or malignant haematological condition, and have a CVAD in place. Study details Participants will be randomised (i.e. allocated by chance) to receive either the normal saline (10ml of 0.9% sodium chloride), heparinised saline (1-2ml of sodium heparin 10units/ml or 100units/ml depending on the device and standard operating procedures), or KiteLock (1-2ml of 4% T-EDTA) administered into the lumen of the CVAD. The solution will be administered at a frequency based on clinical requirement (i.e. if the CVAD is de-accessed), plus during routine management procedures (e.g. needleless connector changes, totally implanted device needling, line cares) with a maximum of one dose per 24 hours. This will continue until the device is removed, the participant withdraws from the study, for up to a maximum of 3 months post-enrolment. Throughout this study period, participants may be assessed by their treating clinicians for bloodstream infections using blood cultures, for CVAD-associated thrombosis (i.e. blood clots) with ultrasound or venography, for blockages of the CVAD with a test of injection and/or aspiration catheter occlusion, and for CVAD failure requiring removal. Participants will also be monitored for any adverse events, with a research nurse contacting them twice weekly across the study period. A questionnaire assessing health-related quality of life will be given to participants at the trial commencement and completion. Participants will additionally be followed up at 1 and 5 years after study completion (using medical records only) to assess for any serious CVAD complications, and for any cause of death. It is hoped that this study may help to identify the locking solution with the least complications and adverse effects, in order to prevent harm in children with a CVAD undergoing treatment for cancer.