Our facility (university hospital - Belgium) uses the BPS (Behavioural Pain Scale) for this purpose and naturally as Sun0408 has said common sense. I included an article about BPS (BPS
Our normal sedation strategy always includes a continuous sedative (propofol or midazolam) and a continuous opioid (remifentanil or sufentanil) for pain management. Second line sedation usually involves continuous ketamine. We might add paracetamol IV q 6 hours based on the likelihood of weaning/extubation and body temperature.
We register pain scale at least q 8 hours in our PDMS (it is an automated order upon admission). It is also registered whenever we validate an order for any pain killer.
It works via a pop-up menu that consists of a page with all the body zones that you can check/uncheck to indicate where the pain is located, or we check "generalized pain". There is also a box that indicates the rational for giving pain meds: either the zones above, prevention, added sedation, shivering, and "others". You can also indicate you didn't give any meds just did the assessment and will follow-up.
Then there is the VAS or the normal painscores you can indicate for verbal patients and there is a section that holds the BPS. One of these three needs to be filled out before the system allows you to close the window and continue working with the PDMS.