REcovery from DEXmedetomidine-induced Unconsciousness

Eligibility Criteria

• * Between the ages of 18 to 65
• * Normal body weight and habitus, body mass index (BMI) 18 to 30 kg/m2
• * Non-smoker
• * No history of taking stimulants or substance abuse
• * For women: either use of hormonal contraception, or \> 45 years old and last menstrual period \> 12 months ago in the absence of any contraceptives.
• * American Society of Anesthesiologists (ASA) physical status classification 1 (ASA 1)
• * Fluent in English (sufficient to communicate with the study team and understand the consent form)
• * Neurologic: epilepsy or positive history of a seizure, stroke, central disorders of hypersomnolence, neuroimmunological disorder (e.g. multiple sclerosis), Meniere's disease, Parkinson's disease, peripheral neuropathy, no significant visual or hearing impairments, findings in the clinical examination suggesting a neurologic disorder
• * Psychiatric: history or treatment for an active psychiatric problem (including Attention-Deficit / Hyperactivity Disorder (ADHD) and anxiety disorder)
• * Cardiovascular: hypertension, symptomatic hypotension or bradycardia, myocardial infarction, coronary artery disease, peripheral vascular disease, dysrhythmias, congestive heart failure, cardiomyopathy, valvular disease, familial history of sudden cardiac death
• * Respiratory: bronchitis, asthma, chronic obstructive pulmonary disease, smoking, shortness of breath, sleep apnea
• * Gastrointestinal: esophageal reflux, hiatal hernia, ulcer
• * Hepatic: hepatitis, jaundice, ascites
• * Renal: acute or chronic severe renal insufficiency
• * Reproductive: pregnancy, breast-feeding
• * Endocrine: diabetes, thyroid disease, adrenal gland disease
• * Hematologic: blood dyscrasias, anemia, coagulopathies
• * Musculoskeletal: prior surgery or trauma to head neck or face, arthritis, personal or family history of malignant hyperthermia
• * Medications: regular use of prescription and non-prescription medications expected to affect central nervous function, anticoagulant or thrombocyte-aggregation inhibiting therapy; exception: oral hormonal contraception
• * Allergies: dexmedetomidine, phenylephrine, betablockers (including labetalol and esmolol), hydralazine, glycopyrrolate