Santos, Eduardo José Ferreira dos, Maria Madalena Jesus Cunha Nunes, Daniela Filipa Batista Cardoso, João Luís Alves Apóstolo, Paulo Joaquim Pina Queirós, and Manuel Alves Rodrigues. 2015. “ Effectiveness of Heparin Versus 0.9% Saline Solution in Maintaining the Permeability of Central Venous Catheters: A Systematic Review ”. Revista Da Escola De Enfermagem Da USP 49 (6):995-1003. https://doi.org/10.1590/S0080-623420150000600017.