Physicians use the program to enter TPN orders into the computer for patients who cannot take in food orally. The program evaluates the orders for completeness, compatibility, and patient safety. If the order "passes" all of the rules based logic, then the order is printed and saved so that preparation in the pharmacy or offsite compounding facility can begin.

As with Neonatal Assistant, Pediatric Assistant decreases errors which occur naturally in a manual system. Prior to implementation of the program, the physician would write an order for the TPN. This order requires many complex and tedious calculations to ensure that the correct amounts of all ingredients are used. There are also many compatibility issues with elements in the TPN, and errors could lead to salt precipitation that could prove fatal for the patient. Once the physician was finished with the handwritten order, it would then be transmitted to the pharmacy department when it would be entered into the computer by pharmacy staff. The pharmacist would have to verify all calculations and drug interactions. This process was very time consuming. Once errors were detected in the order, the physician would have to be contacted by pager or phone to make the necessary corrections.