What is this chocolate milk in my circuit? A cause of acute clotting of a continuous renal replacement circuit: Answers

Factors influencing the patency of continuous renal replacement therapy (CRRT) circuits include catheter size and location, choice of anticoagulant, blood flow and replacement fluid flow rates, ultrafiltration rates (filtration fraction), hematocrit, platelet count, blood product transfusion as well as levels of sedation and paralysis of patients in the intensive care unit.

Early clotting of CRRT circuits leads to blood loss, decreased efficacy, and increased costs.

First, it is important to assess the course of events. What was happening when the circuit went down? Was the patient adequately sedated, or was he moving? The catheter placement and flow should be checked to ensure that nothing was blocked or kinked. The dialysis prescription including blood flow and replacement fluids should be reviewed to ensure adequacy for the patient’s body surface area. The transmembrane pressure (TMP), filter pressures, return line pressures, and ultrafiltration rate of the circuit should be reviewed, as should the activated clotting time (ACT) and heparin dose, or ionized calcium levels and citrate dose, depending on the anticoagulant used. It is also important to look at the circuit. Close examination of the “clot” in the tubing of this circuit revealed a milky appearance, which was unusual and prompted further investigation to examine possible sources of lipemic or chylous build-up. Blood work, including hematocrit and platelet count, should be reviewed. In this patient, in retrospect, triglyceride levels were extremely elevated.

Physicians should be mindful of hypertriglyceridemia as a potential risk factor in critically ill patients receiving parenteral nutrition who have recurrent clotting of CRRT circuits. At our center, we currently monitor triglyceride levels once a week in patients on total parenteral nutrition (TPN). Closer monitoring of triglyceride levels is required in patients with elevated levels and the dose of fat emulsion administered should be adjusted accordingly.