Assessing Covert Consciousness in Unresponsive Patients

Consciousness Disorders Clinical Trial

Official title:

Assessing the Potential for 'Covert Consciousness' in Unresponsive Patients

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT02659228
• Other study ID #: 13-784
• Status: Not yet recruiting
• Phase: N/A
• First received: January 8, 2016
• Last updated: October 25, 2016
• Start date: December 2016

Study information

• Verified date: October 2016
• Source: University of Michigan
• Contact: n/a
• Is FDA regulated: No
• Health authority: Canada: Ethics Review Committee
• Study type: Interventional

Clinical Trial Summary

In this study, the investigators explore anesthesia as a tool for providing further insight into the level of consciousness of individuals with a clinical diagnosis of unresponsive wakefulness syndrome (UWS), but who possess some neurophysiological signatures of conscious awareness. This group, who could potentially be conscious, will herein be referred to as the target population. Our goal is to assess whether or not neurological patterns of consciousness in the target population respond to anesthesia in a similar manner to neurologically compromised individuals with known consciousness (e.g. those in minimally conscious state (MCS). In healthy controls, propofol-induced unconsciousness results in an elimination of the mismatch negativity event-related brain potential (ERP) and a diminished directed connectivity. The investigators hypothesize that at doses well below those required for surgery, anesthesia will have similar effects on these neural patterns in neurologically compromised patients with the potential for conscious awareness, but will not affect these patterns in those who lack consciousness.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 60
• Est. primary completion date: June 2017
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 50 Years

Eligibility

Inclusion Criteria:

• Patients admitted to the intensive care unit at Hamilton General Hospital who:

• Clinical status consistent with UWS (no responsiveness to commands)

• Clinical status consistent with MCS (minimal response to at least one command)

• Presence of an endotracheal tube (ETT) or a tracheostomy tube

• Between 18 and 50 years of age

Exclusion Criteria:

• • Elevated intracranial pressure (ICP)

• Hepatic or renal failure

• Hemodynamic instability

• Active vasopressor therapy

• Previous open-head injury

• Previous intracranial pathology requiring neurosurgical interventions in the past 72 hours

• Anticipated ICU stay < 24 hours

• Documented allergy to propofol

• Pregnancy

• BMI > 35 kg/m2

• Anyone who is deemed medically unsuitable for this study by the attending intensivist

• Patients who are already in a medically-induced coma for intracranial hypertension or status epilepticus

Study Design

Allocation: Non-Randomized, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Consciousness Disorders

Intervention

Device:
• EEG recording
EEG recording with anesthetic (DIPRIVAN)

Drug:
• Anesthetics, Intravenous
The participant will receive an intravenous infusion of propofol (DIPRIVAN Injectable Emulsion USP 1%, AstraZeneca).

Locations

Country	Name	City	State
n/a

Sponsors (3)

Lead Sponsor	Collaborator
University of Michigan	McGill University, McMaster University

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Asymmetry in feedback vs. feedforward network connectivity	EEG networks will be monitored pre, during and post anesthesia. Directed connectivity will be calculated using phase lag index (PLI) and symbolic transfer entropy (STE) between all combinations of EEG sensors. Average values of feedback connectivity (e.g. from the frontal regions to parietal and occipital regions) will be compared to average values of feedforward connectivity (e.g. from parietal and occipital regions to frontal regions). Positive asymmetry will be correlated to the presence of conscious awareness and negative asymmetry will be correlated to the absence of conscious awareness.	3 hours	No
Secondary	Presence of P300 and N400 event-related potentials	EEG signals will be processed to extract the event-related EEG reactions to the auditory stimulation paradigm. Signals will be average 300 ms post-stimuli and 400 ms post-stimuli to assess the presence of the P300 and N400 event-related potentials. Presence of these event-related potentials will be correlated to the presence of conscious awareness and absence of these event-related potentials will be correlated to the absence of conscious awareness.	3 hours	No