Continuous Renal Replacement Therapy Machine Technology

Continuous renal replacement therapy (CRRT) originally was applied with technology adapted from maintenance hemodialysis. Over the past four decades, CRRT machines have evolved into devices specifically designed for critically ill patients. In this chapter, a brief history of this evolution is provided first, with emphasis on the manner in which changes have been made to address the specific needs of the patient and the users of these devices. Subsequently, specific aspects of modern CRRT machines are discussed, including the user interface, pumps, pressure monitoring, safety features, and anticoagulation capabilities. The basic principles of CRRT membranes and filters also are highlighted, especially with regard to the influence of modality, membrane characteristics, and blood/fluid flows on solute transport. Finally, recent CRRT membrane developments designed to broaden the spectrum of solute removal are addressed.