Patients who are in the intensive care unit after surgery and require mechanical breathing support (intubation and ventilation) usually require sedation to avoid agitation and excessive stress responses. Short-acting sedatives such as midazolam and propofol are the drugs typically used for this. Propofol provides for fast sedation and fast recovery from sedation. Midazolam is slower to sedation and slower for recovery, but may provide some advantages over propofol, such as a lower incidence of hypotension (low blood pressure). This study will look at propofol compared to a product with fast sedation and recovery like that of propofol but with less of a chance for hypotension like with midazolam. Patients will be treated with the product for up to 8 hours and then will be monitored for 8 hours following treatment.

Patients who are intubated and ventilated and will require up to 8 hours of sedation in the ICU are eligible for participation in this study. Patients will be randomized to receive 1 of 3 treatments. One treatment is standard of care, a propofol infusion. The other two treatment arms are infusions of GPI 15715 (AQUAVAN), one with a bolus and one without.

Patients will be treated for up to 8 hours and monitored for eight hours post treatment. If there are signs of agitation during the up to 8 hour treatment period, the infusion of the sedative medicine will be increased according to protocol.

Blood samples will be obtained periodically during the course of the study for safety evaluation and pharmacokinetic assessments. When the patient is ready for extubation or the end of the 8 hour study period has been reached, the infusion of the sedative agent will be discontinued and the patient will be monitored for 8 hours post treatment.

Guilford Pharmaceuticals was acquired by MGI PHARMA on October 3, 2005.

Inclusion Criteria:

1. Require 2 to 8 hours of intubation and mechanical ventilation following elective surgery
2. American Society of Anesthesiologists (ASA) status of I-IV

Exclusion Criteria:

1. Requires emergency agency
2. Requires neuromuscular blockers during sedation
3. Requires use of epidural drug administration during sedation