Risks related to catheter locking solutions containing concentrated citrate

Abstract

Risk analysis. Citrate chelates with the calcium ions in blood and tissue. Serious symptoms have been reported when the ionized calcium blood level decreases to 0.6 mmol/l [3]. In vitro tests in which a double lumen central venous catheter is filled with a locking solution equal to the filling volume show that ∼15% of the locking solution is immediately injected into the patient [4]. The injection is normally done within 1–2 s and the overspill distributes in a volume equal to 1–2 heart beats (∼100 ml). Examples of FUE resulting in spillage of more locking solution into the patient include simple mistakes in the lock volume, two instillations of solution into the same lumen and deliberate overinjection of solution to clear a blocked catheter. In the risk analysis we selected an overinjection of 1 and 5 ml.