Consider the following two scenarios:
Treatment
Scenario 1
The propofol infusion of the first patient has no analgesic properties. An IV bolus of morphine may reduce pain perception and therefore reduce propofol requirements (and associated propofol related hypotension). If the patient were tachycardic and remained so post opiate, this would support hypovolaemia as a potential cause rather than pain.
Scenario 2
This patient may well be for tender loving care, CT scan optional. It would be in her interest to give 1-2 mg of morphine for comfort and check for and address a full bladder.