Renal replacement therapy for the critically ill--precarious progress. Part I. Definitions and physiological aspects

Area of Science:

• Nephrology
• Critical Care Medicine
• Intensive Care Unit Management

Background:

• Renal replacement therapy (RRT) has undergone significant evolution over the past 15 years.
• This evolution has led to diverse techniques and terminology, causing ambiguity in clinical practice.
• Continuous versus intermittent RRT techniques present theoretical advantages for critically ill patients.

Purpose of the Study:

• To define terms and techniques in renal replacement therapy.
• To discuss the physiological aspects of RRT.
• To provide a prescription for effective RRT in critically ill patients.

Main Methods:

• Review of current literature on renal replacement therapy techniques.
• Discussion of physiological principles underlying continuous and intermittent RRT.
• Definition of terminology to reduce confusion.

Main Results:

• Theoretical advantages of continuous RRT include hemodynamic stability, rapid metabolic correction, precise fluid management, cytokine clearance, and enhanced respiratory function.
• Limited clinical evidence currently supports these theoretical benefits.
• A definitive reduction in mortality or morbidity associated with continuous RRT has not yet been demonstrated.

Conclusions:

• While continuous renal replacement therapy offers potential benefits for critically ill patients, further clinical evidence is required.
• Standardization of terminology and techniques is crucial for effective RRT implementation.
• Part I of this review focuses on definitions and physiological aspects; Part II will cover technical aspects and RRT prescription.