I work in a Level 1 trauma center in a 32 bed Medical Surgical ICU, we are also a teaching facility. We often use Diprivan gtts as well as fentanyl gtts as our standard sedation, but also use ativan, morphine gtts as well. We do use PRN ativan, morphine, fentanyl and dilaudid IVP to maintain sedation. I feel alot has to do with to treatment plan and if extubation is foreseen in the next 8 hours then PRN would be appropriate. I believe daily awakening is very important to the ventilated ICU pt to check on underlying issues not seen while sedated.