Enteral nutrition, also known as tube feeding, is a method of delivering nutrients directly to the gastrointestinal tract for individuals who cannot meet their nutritional needs through oral intake alone. When it comes to the method of delivery, a critical distinction is made between an open and a closed feeding system. These systems have different protocols for preparation and administration, which in turn affect the risk of contamination, the time and labor involved, and the overall cost.
Understanding the Open Feeding System
An open feeding system is a method where the nutritional formula is not a self-contained unit. It requires the caregiver to manually transfer the liquid formula from its original container (e.g., a can or bottle) into a separate, non-sterile feeding bag. This system is more hands-on and offers more flexibility, but it introduces several points of potential bacterial contamination.
- Formula Source: Comes in individual cans, bottles, or as a powder that must be reconstituted with water.
- Preparation: Involves multiple manual steps, including opening the can, pouring the formula into the feeding bag, and preparing any powdered formulas.
- Risk Factors: The multiple manipulations and exposure to the environment increase the risk of introducing bacteria into the feed. This is particularly concerning in hospital settings or for immunocompromised patients.
- Hang Time: Because of the increased contamination risk, the formula's hang time (the maximum time it can be hung at room temperature) is limited, typically to 4 to 8 hours.
- Cost: Often has a lower initial unit cost for the formula and can allow for the use of more customized or modular diets, where extra vitamins, proteins, or medications are added. However, increased nursing time and potential for formula waste can raise the overall cost.
Understanding the Closed Feeding System
A closed feeding system is a pre-filled, ready-to-hang (RTH) bag of sterile formula that is directly connected to the administration set and feeding tube. This system is a self-contained unit, requiring minimal handling and no pouring or mixing of the formula before administration.
- Formula Source: Comes in a sterile, collapsible bag or container.
- Preparation: Requires minimal handling. The caregiver simply spikes the bag with the administration set and hangs it on a pole.
- Risk Factors: The sealed, non-air-dependent nature of the system minimizes exposure to the environment, drastically reducing the risk of bacterial contamination. This is the preferred method for high-risk patients.
- Hang Time: Due to its sealed, sterile nature, a closed system has a significantly longer hang time, often 24 to 48 hours.
- Cost: Has a higher unit cost for the pre-packaged formula and bags. However, it can be more cost-effective overall due to less formula waste and reduced nursing labor.
What is the difference between an open and closed feeding system?: A Comparison
| Feature | Open Feeding System | Closed Feeding System |
|---|---|---|
| Handling | Involves pouring from cans/packets, requires more caregiver manipulation. | Minimal handling required; formula is pre-filled and ready to hang. |
| Contamination Risk | Higher risk due to exposure during preparation and pouring. | Lower risk due to the sterile, sealed nature of the bag. |
| Formula Hang Time | Shorter hang time, typically 4 to 8 hours. | Longer hang time, typically 24 to 48 hours. |
| Labor/Time | More labor-intensive and time-consuming for preparation and refilling. | Less time-consuming, freeing up nursing staff for other tasks. |
| Cost | Lower initial product cost, but higher overall cost due to labor and waste. | Higher initial product cost, but more cost-effective overall due to less waste and labor. |
| Flexibility | Higher flexibility for mixing different products, modular feeds, or personalized diets. | Less flexibility for adding modular components once the bag is spiked. |
| Nutritional Delivery | Can be less consistent due to variations in preparation or shorter hang times leading to missed feeds. | Often provides more reliable and consistent nutritional delivery. |
Advantages and Disadvantages of Each System
Advantages of a Closed System
- Reduced Infection Risk: By minimizing handling and exposure to the environment, the risk of bacterial contamination and subsequent infection is greatly reduced. This is a primary benefit for critically ill or immunocompromised patients.
- Increased Efficiency: Less nursing time is spent on preparing and hanging feeds, allowing for more time dedicated to direct patient care.
- Less Formula Waste: With a longer hang time, there is less need to discard partially used formula at the end of a shift, which was common in open systems.
- More Accurate Delivery: Studies suggest that closed systems may result in a higher percentage of the prescribed nutritional volume being delivered to the patient.
Disadvantages of a Closed System
- Higher Initial Cost: The pre-filled, ready-to-hang bags typically cost more per unit than canned formulas.
- Less Flexibility: It is more difficult to add customized nutrients, fiber, or medications directly into the sealed bag. Any additions must be administered separately or through different ports.
Advantages of an Open System
- Customization: The ability to add modular supplements or specialized ingredients allows for greater dietary customization based on the patient's specific nutritional needs.
- Lower Initial Cost: The formula, whether in cans or powder, is generally cheaper on a per-unit basis.
Disadvantages of an Open System
- High Contamination Risk: The greatest disadvantage is the heightened risk of bacterial growth, especially with longer hang times, which can lead to serious patient infections.
- Increased Labor: Requires more time for nurses or caregivers to prepare and refill the feeding bags throughout the day.
- Increased Waste: With a shorter hang time, any unused formula must be discarded, leading to more product waste.
Selecting the Right System for Your Needs
For most hospital settings, especially for critically ill or immunocompromised patients, a closed feeding system is the standard of care due to its superior safety profile. National guidelines often endorse its use to minimize nosocomial infections.
In contrast, home enteral feeding, particularly for intermittent or bolus feeds, may utilize open systems. Bolus feeding involves administering a larger volume of formula over a shorter period using a syringe, making a pre-filled bag less practical. In this case, the lower risk of contamination for home care can make an open system a viable option, provided that meticulous hygienic practices are followed. For home use, a dietitian should provide clear instructions on proper handling and storage to mitigate risks. In cases requiring continuous feeding, a sealed, ready-to-hang system can still be beneficial for home use by reducing the caregiver's burden and risk of error.
Conclusion
In summary, the choice between an open and closed feeding system revolves around a trade-off between customization and flexibility versus safety and convenience. Open systems offer lower initial costs and greater adaptability but come with a higher risk of contamination and require more labor. Closed systems, while more expensive per unit, offer a safer, more efficient, and often more reliable method of nutritional delivery, especially for high-risk patients or in clinical settings. The optimal choice is determined by the specific patient's needs, the clinical environment, and an assessment of risk versus benefit by healthcare professionals.
Proper technique is key
No matter the system, adherence to strict hygiene and aseptic techniques is crucial for preventing infection. This includes proper handwashing and sanitizing all surfaces and equipment involved in the feeding process. Following manufacturer guidelines and institutional protocols is essential for the safe administration of enteral nutrition.
- Hygiene is Paramount: Thorough handwashing before and after handling feeding equipment is the most important step in preventing contamination for both systems.
- Read-to-Hang Protocol: For closed systems, it is critical to spike the sterile bag only once with a sterile administration set and replace the tubing and bag every 24 to 48 hours per guidelines.
- Open System Guidelines: For open systems, formula should be handled using clean techniques. The feeding bag should be discarded and replaced every 24 hours, and only an 8-hour supply of formula should be hung at a time.
- Flush the Tube: Regular flushing of the feeding tube with water is necessary to prevent clogging, which is a potential complication for both systems.
- Monitor Patient: Healthcare providers and caregivers should monitor for signs of intolerance or complications, such as gastrointestinal upset or infection, regardless of the system used.
Final considerations
The decision regarding the use of an open versus a closed feeding system should be a collaborative one, involving healthcare providers, dietitians, and caregivers. The patient's underlying medical condition, susceptibility to infection, and setting of care are all determining factors. While closed systems have become the gold standard in acute care settings due to their safety benefits, open systems still have a place in specific clinical or home care scenarios where greater formula flexibility is required, as long as stringent hygiene protocols are followed.
Choosing the optimal feeding strategy
Ultimately, the goal is to provide safe and effective enteral nutrition that meets the patient's specific metabolic demands. The system chosen is a tool to achieve that, and its success is dependent on both the system's inherent safety features and the proper technique of the individual administering the feed. Education and adherence to best practices are the cornerstones of ensuring positive patient outcomes.
