EEG Studies of Ketamine General Anesthesia

Study Overview
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Brief Summary
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We are doing this research study to find out how and where ketamine acts in the brain. Ketamine is an anesthetic (a drug or agent used to decrease or eliminate the feeling of pain by putting you in an unconscious state). We will look at the brain using a machine that records the brain's electrical activity, called an electroencephalogram (EEG). We will assess how it impacts patient's pain responses.

Detailed Description
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In this trial, participants will be given ketamine at a high enough dosage to induce general anesthesia. EEG recording will be conducted during this time. Cognitive assessments and pain monitoring will be administered at various points before and after ketamine induction.

Official Title
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Electroencephalogram Studies of Induction and Recovery From Ketamine-Induced General Anesthesia

Conditions
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Anesthesia

Intervention / Treatment
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* Drug: Ketamine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Between the ages of 18 to 45 Normal body weight and habitus, BMI less than or equal to 30 Non-smoker American Society of Anesthesiologists (ASA) physical status classification P1 Exclusion Criteria: Cardiovascular: myocardial infarction, coronary artery disease, peripheral vascular disease, arrhythmia, congestive heart failure, valvular disease, hypertension Respiratory: bronchitis, chronic obstructive pulmonary disease, smoking, shortness of breath Hepatic: hepatitis, jaundice, ascites Neurologic: seizure, stroke, positive neurologic findings on neurologic examination, multiple sclerosis, Meniere's disease, Parkinson's disease, neuropathy, peripheral stenosis Gastrointestinal: esophageal reflux, hiatal hernia, ulcer Endocrine: diabetes, thyroid disease Renal: acute or chronic severe renal insufficiency Hematologic: blood dyscrasias, anemia, coagulopathies, on anticoagulant therapy Musculoskeletal: prior surgery or trauma to head neck or face, arthritis, personal or family history of malignant hyperthermia Psychiatric: history or treatment for an active psychiatric problem, depression Reproductive: pregnancy, breast-feeding Medications: regular use of prescription and non-prescription medications expected to affect CNS function, St. John's Wort Allergies: labetalol, ondansetron, glycopyrrolate, ketamine, midazolam

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ketamine<br>15 subjects undergoing ketamine general anesthesia. | Drug: Ketamine<br>* Subjects' brain waves will be monitored by EEG recording under ketamine general anesthesia over the course of approximately 60 minutes. Patients pain and dissociation will be assessed before the induction of ketamine and periodically after. Approximately 1 hour after ketamine induction, Midazolam will be administered to reduce patient dissociation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Average Pain Intensity Pre- and Post-Ketamine Induction | Average Pain Intensity prior to ketamine induction, 30 minutes post ketamine, 60 minutes post ketamine, 75 minutes post ketamine, and 120 minutes post ketamine. PROMIS Pain Intensity 1a was used to assess pain delivered by a pre-calibrated pain cuff. Scale of 0 (no pain) to 10 (worst imaginable pain). | Approximately 125 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Average Dissociation States Score Pre- and Post-Ketamine Induction | Patients were assessed for dissociation states prior to the induction of ketamine and at 60 minutes, 75 minutes, and 120 minutes after Ketamine was administered. The Clinician Administered Dissociation States Scale was used to measure dissociation. Each section is scored 0 (not at all) to 4 (extreme), and totaled. The minimum total score is 0 (best, no dissociation at all) and the maximum total score is 92 (worst, the most dissociation). | About 125 minutes | 
| Difference of the Mean Clinician Administered Dissociative States Scale Before and After Midazolam Administration | Midazolam was administered approximately 60 minutes after the administration of Ketamine in order to reduce the effects of Ketamine on dissociation. Dissociation was measured using the Clinician Administered Dissociative States Scale. Each section is scored 0 (not at all) to 4 (extreme), and totaled. The minimum total score is 0 (best, no dissociation at all) and the maximum total score is 92 (worst, the most dissociation). The difference of the mean Clinician Administered Dissociative States Scale before and after Midazolam administration was found. | About 60 minutes |