Study to Evaluate Hemodynamic Effect of Different Loading Doses of Precedex in Post-surgical Intensive Care Unit (ICU) Patients

Inclusion criteria

• Subject or the subject's legally authorized representative has voluntarily signed and dated the informed consent document approved by the Research Ethics Board (REB).
• Initially intubated and mechanically ventilated adult post-operative subjects in an intensive care setting (e.g., post operative care unit, post anesthesia care unit, etc.) that are expected to require sedation for at least 2 hours.
• Has an American Society of Anesthesiologist (ASA) classification of 1, 2, 3 or 4.

ASA Physical Status Classification System

• P1 A normal healthy subject
• P2 A subject with mild systemic disease
• P3 A subject with severe systemic disease
• P4 A subject with severe systemic disease that is a constant threat to life
• P5 A moribund subject who is not expected to survive without the operation
• P6 A declared brain-dead subject whose organs are being removed for donor purposes.
• If female, subject must be postmenopausal, surgically sterile (bilateral tubal ligation, bilateral oophorectomy or hysterectomy), or practicing at least one of the following methods of birth control:

• hormonal contraceptives (oral, parenteral or transdermal) for at least 3 months prior to study drug administration
• intrauterine device (IUD)
• double-barrier method (condoms, contraceptive sponge, diaphragm or vaginal ring with spermicidal jellies or cream).

Exclusion criteria

• Subjects <18 years of age.
• Subjects with a 2nd degree Mobitz Type II or 3rd degree heart block, unless the subject has a permanent pacemaker or pacing wires are in situ.
• Subjects with a known allergy to dexmedetomidine.
• Hypotension based on repeat assessments prior to (within 15 minutes) starting study drug defined as Systolic BP <90 mmHg or Diastolic BP <60 mmHg.
• Pre-existing bradycardia prior (within 15 minutes) to starting study drug defined as HR <50 bpm.
• Subjects who, in the opinion of the Investigator, have any other condition where the risks of dexmedetomidine would be expected to outweigh its benefits (e.g., cardiogenic shock on >2 vasopressors, death anticipated within 48 hours).