Routine Catheter Lock Solutions in Pediatric Cancer Care: A Pilot Randomized Controlled Trial of Heparin vs Saline

Central venous access devices (CVADs) are integral to cancer care provision. Despite the high prevalence of CVAD complications in children with cancer, preventative strategies are understudied.

The aim of this study was to assess study feasibility, occlusive events, thrombolytic use, adverse events, and direct costs of catheter lock solutions.

A single-center, parallel-group, pilot randomized controlled trial was undertaken at a tertiary-referral pediatric hospital in Australia. Children 18 years or younger with an oncological or malignant hematological condition and a CVAD were eligible. Participants were 1:1 randomized to (1) normal or (2) heparinized (10-100 U/mL; CVAD-type dependent) saline lock solutions.

Of 217 children assessed for eligibility, 61 were recruited and randomized to normal (n = 30; 3850 CVAD days) or heparinized (n = 31; 4036 CVAD days) saline. Eligibility (52%) and recruitment (54%) feasibility targets were not met. Protocol adherence was high (95% assessments), with no attrition. Parent/clinician satisfaction of interventions was high (median, 10/10 clinicians/parents). Complete CVAD occlusion occurred in heparin only (n = 2, 6.7% CVADs; incidence rate [IR], 0.49/1000 CVAD days [0.06-1.78]). Central venous access device partial occlusion was detected in 23.3% of CVADs in heparin (n = 7; IR, 2.73/1000 CVAD days [1.36-4.87]) and 13.8% of CVADs in normal saline (n = 4; IR, 2.59/1000 CVAD days [1.24-4.77]). Thrombolytic agents were used in 16.7% heparin (5 CVADs) and 3.5% normal saline (1 CVAD). Adverse events did not differ between groups.

Multisite randomized controlled trials examining CVAD locks are safe, but strategies and resources to increase recruitment and eligibility are required.

Both routine CVAD lock solutions seem safe but may not prevent all forms of CVAD-associated harm.