Santos, E. J. F. dos; Nunes, M. M. J. C.; Cardoso, D. F. B.; Apóstolo, J. L. A.; Queirós, P. J. P.; Rodrigues, M. A. Effectiveness of Heparin Versus 0.9% Saline Solution in Maintaining the Permeability of Central Venous Catheters: A Systematic Review . Rev. Esc. Enferm. USP 2015, 49, 995-1003.