This may be a very true statement but when reporting this action to a colleague or another healthcare professional in a formal letter, it is better to make the patient more important to you. Think of it like this:
- Are you the only person who can show the patient how to self-inject insulin?
- Will you show them a different technique to the one another colleague would show?
I imagine the answers are no.
To your reader, the showing is more important than who did the showing.
For this reason, passive forms are often used to make the person doing the action less important than the person they are doing it to or even the action they are doing:
the patient was shown how to self-inject insulin.
Here’s another example:
A blood sample was taken (from Mr J) on Tuesday.
The form of this sentence is also passive. It starts with the object [a blood sample] then the passive verb [was taken] and ends with extra information [on Tuesday]. You could include the information in brackets (from Mr J) but if the rest of the letter is about Mr J, the reader would understand this is who the sample was taken from and so it can be omitted.
Need more help with the passive?