When a patient can't meet his nutritional needs by oral or enteral feedings, he may require I.V. nutritional support, also known as parenteral nutrition.
Total parenteral nutrition (TPN) refers to any nutrient solution, including lipids, given through a central venous line. The most common delivery route for TPN is through a central venous line into the superior vena cava. Depending on the solution, it may be used to boost the patient's caloric intake, to supply full caloric needs, or to surpass the patient's caloric requirements.
Bag or bottle of prescribed parenteral nutrition solution 
sterile I.V. tubing with attached extension tubing 0.22-micron filter (or 1.2-micron filter if solution contains lipids or albumin) reflux valve time tape tape alcohol pads electronic infusion pump scale intake and output record sterile gloves syringes filled with normal saline solution for flush.
Make sure the solution, the patient, and the equipment are ready. Remove the solution from the refrigerator at least 1 hour before use. Check the solution against the doctor's order for correct patient name, expiration date, and formula components. Observe the container for cracks and the solution for cloudiness, turbidity, and particles. If any of these is present, return the solution to the pharmacy.
When you're ready to administer the solution, explain the procedure to the patient. Check the name on the solution container against the name on the patient's wristband and use two patient identifiers. Perform hand hygiene. Don gloves and, if specified by facility policy, a mask.
There's an order to it
- In sequence, connect the pump tubing, the micron filter with attached extension tubing (if the tubing doesn't contain an in-line filter), and the reflux valve.
- Insert the filter as close to the catheter site as possible. If the tubing doesn't have luer-lock connections, tape all connections to prevent accidental separation, which could lead to air embolism, exsanguination, or sepsis.
- Squeeze the I.V. drip chamber and, holding it upright, insert the tubing spike into the I.V. bag or bottle. Then release the drip chamber. Next, prime the tubing.
- Invert the filter at the distal end of the tubing and open the roller clamp. Let the solution fill the tubing and the filter. Gently tap it to dislodge air bubbles trapped in the Y-ports.
- If indicated, attach a time tape to the parenteral nutrition container for accurate measurement of fluid intake.
- Record the date and time you hung the fluid and initial the parenteral nutrition solution container.
- Attach the setup to the infusion pump and prepare it according to the manufacturer's instructions. Remove and discard your gloves. Perform hand hygiene.
- With the patient in the supine position, flush the catheter with normal saline solution and put on gloves. Clean the catheter injection cap with an alcohol pad.
- If you'll be attaching the container of parenteral nutrition solution to a central line, clamp the central line before disconnecting it to prevent air from entering the catheter. If a clamp isn't available, ask the patient to perform Valsalva's maneuver or instruct the patient to take and deep breath and hold just as you change the tubing. Or, if the patient is being mechanically ventilated, change the I.V. tubing immediately after the machine delivers a breath at peak inspiration. Both of these measures increase intrathoracic pressure and prevent air embolism.
- Using aseptic technique, attach the tubing to the designated luer-locking port and remove the clamp, if applicable.
- Set the infusion pump at the ordered flow rate and start the infusion. Make sure the catheter junction is secure.
- Tag the tubing with the date and time of change.
Starting the infusion
- Depending on the patient's tolerance, parenteral nutrition is usually initiated at a rate of 40 to 50 mL/hour and then advanced by 25 mL/hour every 6 hours (as tolerated) until the desired infusion rate is achieved. However, when the glucose concentration is low, as occurs in most formulas, you can initiate the rate necessary to infuse the complete 24-hour volume and discontinue the solution without tapering.
Changing solutions
- Prepare the new solution and I.V. tubing as described earlier and put on gloves. Remove the protective caps from the solution containers and wipe the tops with alcohol pads.
- Turn off the infusion pump, close the flow clamps, remove the spike from the solution container that's hanging, and insert it into the new container.
- Hang the new container and tubing alongside the old. Turn on the infusion pump, set the flow rate, and open the flow clamp completely.
- If you'll be attaching the solution to a peripheral line, examine the skin above the insertion site for redness and warmth and assess for pain. If you suspect phlebitis or if the I.V. has been in place for 72 hours, remove the existing I.V. line and start a line in a different vein.
- Next, turn off the infusion pump and close the flow clamp on the old tubing. Disconnect the tubing from the catheter hub and connect the new tubing. Open the flow clamp on the new container to a moderately slow rate.
- Remove the old tubing from the infusion pump and insert the new tubing according to the manufacturer's instructions. Then turn on the infusion pump, set it to the desired flow rate, and open the flow clamp completely. Remove the old equipment and dispose of it properly.
- Always infuse a parenteral nutrition solution at a constant rate without interruption to avoid blood glucose fluctuations. If the infusion slows, consult the doctor before changing the infusion rate.
Check points
- Monitor the patient's vital signs every 4 hours or more often if necessary. Watch for an increased temperature, an early sign of catheter-related sepsis.
- Check the patient's blood glucose every 6 hours. Some patients may require supplementary insulin, which the pharmacist may add directly to the solution. The patient may also require additional subcutaneous doses.
- Change the dressing over the catheter according to your facility's policy or whenever the dressing becomes wet, soiled, or nonocclusive.
- Weigh the patient at the same time every morning. Maintain accurate intake and output records.
- Change the tubing and filters every 24 hours or according to facility policy. (See Documenting total parenteral nutrition.)
Outline