Delirium Prevention With Ketamine in Ear, Nose, and Throat (ENT) Patients

A Randomized Placebo-controlled Pilot Study of Single-dose Intraoperative Ketamine for the Prevention of Delirium in Otolaryngeal Cancer Surgery Patients

The goal of this prospective randomized double blinded placebo controlled study is to investigate if a single dose of ketamine in addition to standard anesthesia will reduce the risk of delirium in otolaryngeal cancer patients postoperatively. Ketamine's effect on post-operative pain and opioid use will be measured as well. Electroencephalogram (EEG) will be utilized during the surgical procedure to evaluate its potential as a possible predictive device for delirium.

This is a single center prospective randomized double blinded placebo controlled study. The primary aim of the study is to optimize the intraoperative treatment protocol for head and neck cancer patients to reduce the incidence of delirium and associated postoperative cognitive dysfunction. Secondary aims are to determine the dose response relationship for intraoperative ketamine and delirium reduction, determine if a single dose of ketamine will reduce post-operative pain and opioid requirements, determine if raw electroencephalogram (EEG) data can predict postoperative delirium during general anesthesia, and to evaluate length of intensive care unit (ICU) and length of hospital stay. Participants will be randomized to one of three groups after administration of general anesthesia; one dose of .5 mg/kg intravenous (IV) Ketamine, 1.0 mg/kg of IV Ketamine, or IV placebo. An EEG will be used during the surgical procedure to gather raw data for off line analysis among patients developing post-operative delirium.

Participants undergoing surgery for otolaryngeal cancer will be randomized to receive one dose of IV ketamine at 0.5 mg/kg.

Participants undergoing surgery for otolaryngeal cancer will be randomized to receive one dose of IV ketamine at 1.0 mg/kg.

Participants undergoing surgery for otolaryngeal cancer will be randomized to receive one dose of IV saline/placebo.

Ketamine will be administered intravenously after administration of general anesthesia and prior to the first surgical incision.

Placebo will be administered intravenously after administration of general anesthesia and prior to the first surgical incision.

A processed EEG device will be used during the surgical procedure to gather raw EEG data for off line analysis among patients developing post-operative delirium.

The CAM-ICU assesses four features: 1) acute change or fluctuation in mental status from baseline, 2) inattention, 3) altered level of consciousness, and 4) disorganized thinking. The measure reports whether a participant meets criteria for delirium by summing the number of features answered as "present". Feature 1 plus 2 and either 3 or 4 present = delirium positive. Results are expressed as number of participants with or without delirium at each time frame.

Baseline, Post Surgery (PACU), Post surgery (POD 0), Post surgery (POD 1), Post surgery (POD 2), Post surgery (POD 3), Post surgery (follow up visit - Up to 6 weeks)

The Mini-Cog is a 3-minute instrument that can increase detection of cognitive impairment. A score ranging from 0-2 indicates positive screen for dementia. A score ranging from 3-5 indicates negative screen for dementia.

The MMSE is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. Any score greater than or equal to 24 points (out of 30) indicates a normal cognition. Below this (0-24), scores can indicate cognitive impairment.

The CFQ is a 25-item self-report measure of failures in attention, perception, memory, and action. Participants are asked to indicate on a 5-point scale how often they have experienced each failure in the past months, from 0 (never) to 5 (very often). Scores range from 0 to 100 a higher score indicating more failures in attention.

Post Intervention (Intraoperative), Post Intervention (POD 0), Post Intervention (POD 1),Post Intervention (POD 2),Post Intervention (POD 3), Post Intervention (Follow up visit-up to 6 weeks post intervention)

The investigators compared the relative beta power derived from the normalized power spectral density (PSD) in patients with and without PACU delirium (positive and negative delirium). Only a total of 38 EEGs with sufficient quality were analyzed. Results are expressed in percentage of cumulative power. A higher beta power correlates with worse outcome. Averages and standard deviations are shown.

Inclusion Criteria: Current diagnosis of otolaryngeal cancer and undergoing surgery with general anesthesia Competent to provide informed consent Exclusion Criteria: Emergency surgery Monitored Anesthesia Care (i.e., regional anesthesia alone without plans for general anesthesia) Surgery involving the eye, eyebrow, forehead, or frontal scalp near the sensor placement Poor health literacy Allergy, or have experienced any drug reaction to ketamine Pregnant or lactating Currently in active alcohol withdrawal Taking buprenorphine for chronic pain