A catheter is a thin, flexible tube inserted into the body for medical purposes, such as delivering medications or fluids, or draining bodily fluids. The term “occlusion” refers to a blockage within this medical tube. Catheter occlusion is a common issue that can interrupt medical treatment.
Understanding Catheter Occlusion
Catheter occlusion occurs when a partial or complete blockage prevents the catheter from functioning as intended. This can manifest as an inability to infuse fluids, draw blood, or drain urine, depending on the catheter’s purpose.
A partial occlusion means the catheter is still somewhat functional, but flow is restricted. For instance, fluid might be infused, but withdrawing blood becomes difficult or impossible, or the flow appears sluggish. In contrast, a complete occlusion indicates a full blockage, where neither infusion nor aspiration of fluids is possible through the catheter. This complication is frequent in healthcare settings, with an estimated 14% to 36% of patients experiencing catheter occlusion within one to two years of placement.
Recognizing the Signs
A common indication of catheter occlusion is difficulty or inability to flush the catheter. For an intravenous line, an inability to draw blood or a sluggish blood return can signal a problem.
Resistance when pushing fluids through the catheter may also point to an occlusion. Pain, swelling, or redness at the catheter insertion site can accompany an occlusion. Leakage of fluid around the insertion site or an altered or absent flow from the catheter, such as no urine draining from a urinary catheter, are also signs. Additionally, infusion pumps may display frequent occlusion alarms, alerting caregivers to a potential blockage.
Common Causes of Occlusion
Catheters can become occluded for several reasons, broadly categorized as thrombotic or non-thrombotic. Thrombotic occlusion, involving the formation of blood clots, is the most common cause, accounting for approximately 58% of all catheter blockages. These clots can form inside or at the tip of the catheter, often due to blood reflux into the line or inadequate flushing techniques. A “fibrin sheath” can also develop, where fibrin, a protein involved in clotting, accumulates around the catheter, sometimes completely covering its tip.
Non-thrombotic occlusions represent about 42% of all catheter blockages. Mechanical issues are a significant non-thrombotic cause, including kinking of the catheter tubing, improper clamping, or the catheter tip resting against a blood vessel wall. Another cause is chemical or drug precipitation, which occurs when incompatible medications or solutions are mixed, forming solid particles that accumulate within the catheter lumen. Lastly, infectious occlusion can arise from the formation of a microbial biofilm inside the catheter, where bacteria or fungi create a sticky layer that narrows the lumen.
Managing and Preventing Occlusion
Initial attempts to manage catheter occlusion might involve flushing the catheter with saline, which can resolve some mechanical blockages. For thrombotic occlusions, specific medications known as thrombolytic agents, such as alteplase, are administered to dissolve the blood clot. In some cases of mechanical occlusion, trained medical staff may attempt physical manipulation of the catheter or adjust the patient’s position to clear the blockage. If these methods are unsuccessful, the catheter may need to be removed and replaced. It is important to emphasize that patients or caregivers should never attempt to clear an occlusion themselves.
Prevention of catheter occlusion involves consistent and proper care. Regular and correct flushing techniques with saline are important to maintain catheter patency. Caregivers should ensure the catheter tubing is not kinked or clamped incorrectly, and that the catheter is properly secured to prevent dislodgement.
Adherence to aseptic technique during all catheter care procedures helps prevent infectious occlusions. Understanding medication compatibility is also important to avoid chemical precipitation within the line. Prompt reporting of any signs of occlusion to healthcare providers allows for early assessment and intervention.