Thats an interesting point. The fact that the message remained after sending was actually a bug that was fixed, but I see that this had unintended consequences for users like you who 1. wrote a message, 2. sent the message to the nurse, and then 3. saved it to the chart.
The way it was designed was to allow documentation that the nurse handled the message. In this approach, you would 1. write a message, 2. send the message to the nurse, 3. the nurse would reply back to you, noting that she/he had completed the task, 4. you would then save it to the chart. In this way the full documentation path would include that the nurse told you they had done what you ordered. That work?