Ferreira Chacon, J.M., Hato de Almeida, E., de Lourdes Simoes, R., Lazzarin Ozorio, V., Alves, B.C., Mello de Andrea, M.L., . . . Biernat, J.C. (2011). Randomized study of minocycline and edetic acid as a locking solution for central line (port-a-cath) in children with cancer. Chemotherapy, 57, 285–291.

The purpose of the study was to evaluate the efficacy of using heparin versus M-EDA for locking central venous catheters and preventing infection.

Prospective blood cultures were obtained at the beginning of the study and at each chemotherapy session at weekly or monthly intervals according to each chemotherapy protocol. Aseptic technique was used to collect 10 ml of blood for each culture. Cultures obtained from the catheters also were obtained with catheter removal. Primary outcome was positive blood culture or clinical evidence of bacteremia or sepsis associated with the catheter, regardless or whether blood cultures were positive or negative. The catheter-locking solution had the same volume as each catheter’s priming solution. It was slowly introduced (in at least 10 seconds) after each chemotherapy session, and remained in the catheter lumen until the next session.

• The sample consisted of 50 patients, 26 in the heparin arm (group 1) and 24 in the M-EDTA arm (group 2).
• Age range was not given, but patients were classified as pediatric.
• All patients with blood cancers and solid tumors (group 1 contained 16% blood cancers and 10% solid tumors; group 2 contained 16% blood cancers and 8% solid tumors) were included.
• All patients were undergoing chemotherapy, had an implanted port-a-cath CVC, and were clinically stable.
   

Single-site inpatient/outpatient facility in Sao Paulo, Brazil
 

• The phase of care was active treatment
• Application was for pediatrics and CVCs
   

Prospective, randomized study

Blood cultures

A total of 762 serial prospective blood cultures were obtained, 387 from group 1 and 375 from group 2. In group 1, 19 blood cultures were positive and infection incidence was 73.1% (19 of 26 ports); in group 2, five blood cultures were positive and the incidence rate was 20.8% (5 of 24 ports). This difference was significant (p = 0.0001). The colonization of catheters was 5.7 times greater in group 1 than group 2. The mean time free of catheter infection in group 1 was 4.72 months, significantly shorter than in group 2, where it was 9.69 months (p = 0.002). The chances of hospitalization were two times greater for children in the heparin group. There were no side effects observed from either treatment.

The results of this study suggest a significant benefit for children using M-EDTA as a CVC lock as opposed to straight heparin for prevention of catheter-associated infections. The EDTA is a strong cation with chelating properties that destroys the buildup within the lumen. Minocycline is a great broad spectrum antibiotic that is never used for anything but orally for acne.

• Small sample size (less than 100 participants), and too few completed study. 
• No blinding with associated risk of bias.
• It is unclear if differences in hospitalizations between the two groups were related to infection, or if the infection differences seen may have been in part a result of more hospitalizations.
• Specific ingredients and proportions in the solution used are not provided. 
• No subgroup analysis was conducted for hematologic and solid tumors, where infection risk may be very different.  
   

The nurse would not be able to use this without a physician's order, unless it was SOP for that facility. If it were SOP, then nurses could use the solution to flush and lock the CVCs.

This approach shows great promise and would be simple to implement in a clinical setting. Further research is warranted to provide additional support for its efficacy.