Yes. I think I referred to that in my remarks at the beginning. That information is well known, and it's a function of a number of things.
It's a function of belief about the dangers of giving analgesics, although in the setting that you described, that danger is minimized because of the close observation that occurs after cardiac surgery.
It's partly because pain is not routinely assessed. If a researcher comes and asks a patient if he or she has pain, the nurse and physician responsible for caring for the patient may not have done the same thing. So if the nurse has not assessed the patient, if the nurse is not aware that the patient is experiencing pain, the nurse may not deliver the necessary analgesic.
I believe the same study to which you're referring also noted that even when the patients were making their pain known, they did not receive the maximum dose or least-frequent-interval dose, and part of that has to do simply with a lack of awareness of the importance of treating pain. There is an often-said statement that pain never killed anyone, which is actually entirely untrue.