Understanding the Purpose of a Hickman Line
A Hickman line is a type of tunneled central venous catheter (CVC), a thin, flexible tube inserted into a large vein, most commonly in the chest. The catheter is tunneled under the skin to an exit site, usually on the chest wall, and the tip of the catheter is advanced into a large vein near the heart. A dacron cuff on the catheter promotes tissue growth, which helps to anchor it in place and creates a barrier against infection. This design is intended for long-term use, lasting months or even years.
Hickman lines are invaluable for long-term medical treatments that require frequent access to a large vein. While often associated with chemotherapy, blood transfusions, and long-term antibiotic administration, one of its primary uses is delivering total parenteral nutrition (TPN).
How Total Parenteral Nutrition (TPN) Works
Total Parenteral Nutrition (TPN) is a method of feeding that bypasses the gastrointestinal (GI) tract entirely by providing all necessary nutrients directly into the bloodstream. A specialized TPN solution, tailored to a patient's individual needs, is infused through the Hickman line. This solution contains a mix of water, carbohydrates (as dextrose), proteins (as amino acids), fats (as lipid emulsions), electrolytes, vitamins, and trace elements.
TPN is necessary for individuals whose digestive systems are not functioning correctly, or those with conditions that require bowel rest. Some common medical conditions necessitating TPN include:
- Chronic intestinal obstruction
- Intestinal failure due to conditions like short bowel syndrome or severe inflammatory bowel disease
- High-output fistulas
- Severe malnutrition where oral or enteral feeding is insufficient
The Hickman line's placement in a large central vein is crucial for TPN delivery. The high concentration (osmolarity) of the TPN solution would severely irritate or damage smaller, peripheral veins. By delivering the solution into a large vein with high blood flow, it is rapidly diluted, protecting the veins and ensuring nutrients are distributed efficiently throughout the body.
A Comparison of Hickman and PICC Lines
While both Hickman and PICC (Peripherally Inserted Central Catheter) lines are types of central venous catheters, there are distinct differences that influence which is chosen for TPN therapy. The table below highlights these key distinctions.
| Feature | Hickman Line | PICC Line |
|---|---|---|
| Insertion Site | Surgically placed in a large vein, typically in the neck or chest. | Inserted into a peripheral vein, usually in the upper arm, and advanced to a large central vein. |
| Tunneling | A segment is tunneled under the skin, exiting at a site on the chest. | No tunneling; enters the vein directly from the arm. |
| Longevity | Designed for long-term use, often months to years. | Generally used for shorter-term therapy, lasting weeks to months. |
| Infection Risk | Lower infection rate due to the subcutaneous cuff and tunneling, which acts as a barrier. | Slightly higher infection risk compared to Hickman, especially with prolonged use. |
| Patient Mobility | More stable and discreet, allowing for greater patient freedom of movement once healed. | Can be cumbersome and limit arm movements, though patients can often perform normal activities. |
| Placement | Requires a surgical procedure, often in an operating room or interventional radiology suite. | Can be inserted at the bedside by specially trained nurses or doctors. |
For patients requiring long-term, stable access for TPN, a Hickman line is often the preferred choice due to its lower risk of infection and greater durability.
Managing TPN Through a Hickman Line
Proper management of a Hickman line and TPN is critical for patient safety and efficacy. This involves a coordinated effort by a multidisciplinary healthcare team, including nurses, doctors, pharmacists, and dietitians.
Administration and Care Procedures
- Aseptic Technique: Strict sterile technique is paramount during all access and care procedures to prevent infection, a serious risk with any central line. Hand washing and using sterile equipment are essential.
- Dressing Changes: The exit site dressing must be changed regularly according to healthcare provider instructions, typically once a week or whenever it becomes wet, loose, or dirty.
- Flushing: When not in use, the line's lumen is flushed with a saline or heparin solution to prevent it from becoming blocked by blood clots.
- Infusion Schedule: TPN is often infused cyclically, for example, overnight over 10-12 hours, allowing patients more freedom from the infusion pump during the day.
- Monitoring: Regular monitoring is required to check for metabolic imbalances, such as hyperglycemia or electrolyte disturbances, which are potential complications of TPN. Blood tests will be drawn regularly, often from the Hickman line itself.
Potential Complications of TPN and Hickman Lines
While safe and life-sustaining when properly managed, there are risks involved with TPN administration via a Hickman line. These include:
- Infection: Catheter-related bloodstream infections are the most common and serious complication. Symptoms include fever, chills, or redness/swelling at the exit site.
- Occlusion: The line can become blocked by a blood clot or precipitate, preventing it from being used.
- Thrombosis: A blood clot can form in the vein where the catheter tip is located.
- Mechanical Problems: The line can be accidentally pulled out, damaged, or develop a leak.
- Metabolic Issues: Hyperglycemia, hypertriglyceridemia, and electrolyte imbalances are potential metabolic complications.
Conclusion
In summary, a Hickman line is an effective and safe way to receive nutrition intravenously for patients who cannot use their digestive system. The process, known as Total Parenteral Nutrition, involves infusing a nutrient-rich solution directly into the bloodstream via a central line. Proper care and monitoring by a dedicated healthcare team are essential to minimize risks such as infection and metabolic complications. The choice between a Hickman and other central lines depends on the patient's specific needs, expected duration of therapy, and overall health status. When managed correctly, a Hickman line can significantly improve the quality of life for individuals requiring long-term nutritional support. To learn more about living with a central line, including managing infusions at home, Macmillan Cancer Support offers comprehensive patient information.
