A technique for rapid exchange of continuous renal replacement therapy.

Re-initiation of continuous renal replacement therapy (CRRT) in neonates and young infants weighing less than 15 kg often necessitates a blood prime of the blood circuit path or a concurrent packed red blood cell (PRBC) transfusion to avoid causing hemodynamic instability due to acute hemodilution. The significant amount of time required for a routine CRRT circuit change can be associated with worsening electrolyte and acid-base abnormalities, fluid retention, greater hemodynamic instability and reducing effective hemofiltration time. In an attempt to limit the time without CRRT and to eliminate the requirement for additional blood exposure, a new technique, rapid exchange of continuous renal replacement therapy (RECRRT), was developed. Rapid exchange of continuous renal replacement therapy is a sequential technique that transfers citrated blood from one CRRT machine to another machine connected in series. The technique effectively negates the requirement for CRRT circuit path blood priming or PRBC transfusion. The amount of time without CRRT is markedly reduced by RECRRT to 2-3 min. The RECRRT technique has been utilized more than 30 times for at least 15 patients without an adverse event. RECRRT may benefit children who weigh less than 15 kg and in those patients who experience hemodynamic or clinical instability while CRRT is discontinued for only a brief period.

Renal handling of potassium.

Under normal physiologic conditions, the kidney is the organ chiefly responsible for the maintenance of potassium balance. Knowledge of the physiologic properties of the distal nephron that affect potassium secretion allows for a better understanding of how potassium excretion can be modulated. This article will review the normal renal handling of potassium and the factors responsible for maintaining potassium balance.