A Safety and Efficacy Study of Patients Requiring Sedation for Elective Awake Fiberoptic Intubation.

• The percentage of subjects requiring rescue midazolam to achieve and/or maintain
• proper sedation levels throughout the study drug infusion.

• Total dose of rescue midazolam required to achieve and/or maintain target sedation
• levels; percentage of subjects requiring additional rescue medications other
• than midazolam to achieve and/or maintain target sedation levels;
• anesthesiologist assessment of ease of subject care; and subject recall and
• satisfaction assessed 24 hours post study drug.

The purpose of this study is to evaluate the safety and efficacy of dexmedetomidine versus placebo used for sedation during elective awake fiberoptic intubation.

An awake fiberoptic intubation is indicated for any patient with an anticipated difficult airway because of their anatomy, airway trauma, morbid obesity, or unstable cervical spine injuries. An awake fiberoptic intubation in a non-sedated patient can be extremely stimulating, uncomfortable, and unpleasant. The clinician must focus on maintaining spontaneous breathing, hemodynamic stability, and the patient's comfort. The term "awake" fiberoptic intubation is used to distinguish this procedure from fiberoptic intubations performed under general anesthesia. Although patients may be sedated for "awake" fiberoptic intubation, they need to be responsive and capable of maintaining their own airway without assistance. Vital components of a successful awake fiberoptic intubation include an anesthesiologist experienced in this technique, adequate topicalization of the airway, and a sedated yet cooperative subject.

Benzodiazepines, combined with opioid, are commonly used for anxiolysis and/or analgesia during awake fiberoptic intubations.

Dexmedetomidine has sympatholytic, sedative, analgesic, and anxiolytic effects that attenuate the catecholamine response to perioperative stress. Dexmedetomidine sedates patients by decreasing sympathetic activity and the level of arousal. Furthermore, dexmedetomidine has been found to facilitate a decrease in salivary secretion, a desirable effect during fiberoptic intubations.

An estimated 100 subjects (50 DEX, 50 PBO) scheduled for an elective awake fiberoptic intubation because of a potentially difficult airway will be randomized prior to intubation at approximately 18 investigative sites.

• Drug: Dexmedetomidine
• Drug: Midazolam

Inclusion Criteria:

• Adult (18 years of age);
• ASA score I - IV inclusive;
• Requiring awake fiberoptic (oral or nasal) intubation because of anticipated difficult airway

Exclusion Criteria:

• Previous exposure to any experimental drug within 30 days prior to study drug administration;
• Central nervous system (CNS) disease with an anticipated increased intracranial pressure or cerebrospinal fluid (CSF) leak;
• Uncontrolled seizure disorder and/or known psychiatric illness that could confound a normal response to sedative treatment;
• Presence of acute alcohol intoxication;
• Current (within 14 days of study entry) treatment with an 2-agonist or antagonist;
• Subject for whom benzodiazepines, DEX or other 2- agonists are contraindicated;
• Subject received an IV or PO opioid within one hour or intramuscularly within four hours of the start of study drug administration;
• Subject has acute unstable angina, laboratory confirmed acute myocardial infarction within the past 6 weeks, heart rate <50 bpm, systolic blood pressure (SBP) <90 mmHg, or complete heart block unless they have a pacemaker.
• Subject has elevated SGPT (ALT) and/or SGOT (AST) values of > 2 times the upper limit of normal (ULN).
• Subject has any other condition or factor which, in the Investigator's opinion, might increase the risk to the subject.