When should an internal or external drain be capped? When should this drain be uncapped?
After a de novo biliary drainage, catheters are almost always attached to a bag for gravity drainage for a period of time. External drainage helps to decompress the biliary system. A pressurized system may promote bacterial translocation into the hepatic vasculature, resulting in sepsis. Obstructed systems are likely to be pressurized, and this is exacerbated by the contrast material injected into the ducts during the procedure. Pruritus often resolves more quickly if drainage is maximized. In the setting of a malignant obstruction, administration of chemotherapeutic agents may be delayed if the serum bilirubin level is excessively elevated. In certain situations, internal and external drainage may accelerate normalization of the serum bilirubin level and allow for the subsequent administration of chemotherapeutic agents.
Patients with drains attached to external drainage bags can lose a significant amount of fluids and electrolytes. Tubes are commonly capped when possible to allow for more physiologic drainage of bile. Usually this occurs when concerns over infection have subsided and pruritus has resolved. If chemotherapy is planned, tube capping may be delayed until the serum bilirubin level is within an acceptable range.
After a tube has been capped, it should be uncapped if there is concern for infection (fever, elevated white blood cell count, bacteremia, sepsis), leakage of bile around the catheter, pain, or increasing bilirubin or other liver enzyme levels. After the tube is uncapped, additional tests may be indicated, such as a tube check to determine whether the tube is clogged or malpositioned.