RESUMEN
BACKGROUND: The aim of this study is to analyze whether heparin, used as a lock in fully implantable catheter for chemotherapy (portocath), maintains its activity even if it remains in the catheter for a long period of time. METHODS: According to the institutional protocol, all catheters routinely use the lock solution with 3 mL of heparinized solution after chemotherapy and the time interval between each change as lock in the catheters studied ranged from 7 to 30 days. A total of 25 blood samples from 22 patients with 6 types of neoplasia on chemotherapy or not were collected according to routine, and the 10 mL of liquid contained in the first aspirated reservoir/catheter (corresponding to the lock of the last section), were sent for laboratory analysis for prospectively studied with the following tests: anti-Xa, partially activated thromboplastin time (APTT), thrombin time (TT), reptilase, and thromboelastogram. RESULTS: Heparin activity was found in 96% of the anti-Xa and APTT tests. In relation to TT, 92% presented activity. The reptilase test was performed on 24 samples with significant time reduction in all of them. In the INTEM stage, the thromboelastometry test showed activity in 92% of samples and in the HEPTEM phase there was reduction in time in all samples. In all samples, the heparin activity was found to be independent of the time of use. CONCLUSIONS: We can conclude that lock of heparinized solution used in our service in fully implantable central venous catheters for chemotherapy was maintained with active heparin even after a long period of time (up to 30 days), demonstrating that the half-life of the substance within the catheter is greater than its plasma half-life.