The following five principles apply to the care of drainage tubes. It is important that you remember these principles when you are working with patients who have drainage tubes.
1. Closed cavities of the body are sterile cavities. Insertion of any tube must be performed with adherence to the principles of sterile asepsis.
2. A portal of entry that comes into contact with a non-sterile surface immediately renders an otherwise sterile field non-sterile. When disconnecting drainage tubes, such as a urinary catheter or a T-tube, the ends must be kept sterile.
3. Gravity promotes the flow of drainage from a cavity. Keep drainage tubes and collection bags at a lower level than the cavity being drained. Position the tube so the drainage will not have to run upward.
4. Drainage will flow out of the tubing if the lumen is not occluded. Avoid kinks and coils in the tubing and watch that the person does not lie on the tubing. Do not clamp tubes without a doctor’s order.
5. Properly cleanse the site before accessing any tubing to reduce possible introduction of microorganisms into a cavity. Sometimes contrast media and radiopharmaceuticals are injected via the tubing. An alcohol swab may be used to clean the entry point prior to accessing the tubing.
The following four factors affect the flow of fluid through tubes.
1. Pressure difference
- A fluid will flow through a tube only when a pressure difference occurs between the two ends, with fluids moving from the region of higher pressure to the region of lower pressure. The larger the pressure difference, the more flow there will be.
- A liquid in an enclosed container produces pressure by virtue of its weight. Weight, in turn, is determined by the density of the liquid and by the height of the liquid column from its surface to its outlet.
- When liquid flows out of a container, the liquid column becomes shorter and, therefore, has less weight, producing a drop in pressure and a slower flow rate. However, raising the height of the liquid column increases the pressure and speeds up the flow rate.
2. Diameter
- The diameter of a tube is the width of its lumen or inside opening. This diameter has a significant effect on the resistance to fluid flow. Increasing a tube’s diameter increases the flow rate and vice versa.
3. Length
- The length of a tube affects the rate of fluid flow. Fluid is slowed down by the friction of its molecules against the walls of the tube. The longer the tube, the more surface area there is for the fluid to rub against. As well, the friction is greater in narrow tubes because the fluid is near the walls. Tubes should be as short as possible, but long enough to achieve their purpose without unduly restricting the person’s movement.
4. Viscosity
- Viscosity refers to the tendency of a fluid to resist flow because of the friction of its molecules rubbing against each other. This lack of slipperiness causes the fluid to flow slowly. The rate of a slowly flowing fluid can be increased by raising the height of the container to increase the pressure difference; opening the clamp more or using a larger tube so there is a wider diameter; or diluting the fluid to make it less viscous.
Caring for patients with multiple tubes and attachments can be challenging. Follow the guidelines in Table 10.1 to help you care for patients with tubes and attachments.
| Table 10.1 Guidelines for Caring for Patients with Tubes and Attachments | |
| Guideline | Rationale |
|---|---|
| Secure tubes to the skin with tape (non-allergenic or waterproof). A good method of taping is to loop the tape around the tubing, make a “neck” of tape, and secure the tape to the skin (except for nasogastric tubes). This allows some gentle moving of the tube without kinking and protects it from the danger of being pulled out. | When tension is applied to the tube, the stress will be taken by the tape rather than by the tube. |
| Drainage bags should be secured to stretchers, patient gowns, etc., as appropriate. | This prevents undue stress on the drainage tube and/or accidental removal from the wound or body cavity. |
| Connect tube to sterile tubing and drainage receptacle. Do not clamp tubing unless ordered. | This helps keep wound or body cavity sterile and promotes flow of drainage. |
| To ensure continuous drainage, be sure tubing is not kinked, not caught in the bed rails, not underneath the patient, and free from tension when turning, etc. | Any kinks in tubing can stop drainage from the patient and cause further complications. |
| Dressing around tube, if any, should be clean and dry. Sterile technique is used if it is necessary to change the dressing. | This avoids irritation from tube rubbing the skin or from excessive drainage. |
| Record and report patency of tube and amount, colour, character, and odour of drainage. If an unusual situation occurs in your department (i.e., if the bag is full and must be emptied), call for help. If the contents of a drainage tube are spilled, the approximate amount must be reported. | This will help inform ward staff of an unusual situation that happened in your department. |
| If you are unsure how to empty the container or how to close it after a spill, seek help. | Most drainage tubes must have the ends kept sterile. Always follow agency regulations on how to clean up a blood or body fluid spill. |
| Data source: BCIT, 2015a | |
Critical Thinking Exercises
- A patient arrives in your department holding her urinary catheter drainage bag in her hand. What should you do?
- When settling a patient into bed, what factors must be considered to ensure drainage devices are able to flow and drain continuously?
