Effectiveness of the NeuroSENSE for Monitoring the Hypnotic Depth of Anesthesia

Summary

The objective of this clinical study is to investigate whether the NeuroSENSE is an adequate monitor of hypnotic depth-of-anesthesia (DOA). Therefore, this study will investigate whether the information provided by the NeuroSENSE Monitor can help in assessing the hypnotic effect of anesthetics in adult patients undergoing general anesthesia.

Conditions

• Depth of Anesthesia (DOA)

Interventions

DRUG

Propofol induction followed by randomized doses of desflurane

Anesthesia in all patients will be induced with iv propofol 1.5 mg/kg with extra 0.5 mg/kg doses as needed. Anesthesia will be maintained using inhaled desflurane in oxygen/air with the initial desflurane concentration of 1.2 MAC, which will be changed in steps of ±0.4 MAC after reaching the post-intubation steady state. The step changes will be initiated every 7.5 min, as follows: at every level of MAC there is a 1/3 chance in remaining at this level and a 2/3 chance of changing it. The anesthesiologist can accept the change to move to the new level. However, he/she can also reject it to remain at the current level for another 7.5 min. This scheme yields 3 possible desflurane levels: 0.8, 1.2 and 1.6 MAC. The anesthesiologist can also leave the randomization schedule at anytime if clinically indicated, and later re-start it at his/her discretion. All anesthetic doses and their changes fall within conventional dosing.

DEVICE

Recording of EEG using NeuroSENSE

The NeuroSENSE NS-701 system is a 2-channel device for brain activity monitoring in the operating room, intensive care unit, emergency room and other clinical settings. The system acquires and processes electroencephalograms (EEGs) via noninvasive electrodes placed on a patient's forehead. The acquired raw EEG signals and processed EEG variables are continuously displayed for interpretation by the clinician. The proprietary processed variable, WAVcns, quantifies the patient's brain activity, which is typically affected by anesthetic drugs. The system displays processed variables based on 2 bilateral channels (1 per brain hemisphere) for use as a supplement to the anesthesia standard of care. Note: the indications provided by the NeuroSENSE monitor are not used for anesthesia dosing or patient assessment in this study, and the anesthesia provider is blinded to the monitor readings. The device is used only for acquisition of EEG signals and may be used to log the events of interest.

OTHER

Data collection

Non-invasive blood pressure (BP), heart rate (HR), respiratory rate (RR) and electroencephalogram (EEG) will be recorded during the surgery in all subjects. Also, information about all medically significant events, all study-related events (incl. patient's reactions, responses, observations and assessments) and administered medications (incl. end-tidal (ET) desflurane concentration) will be recorded along with time stamps. The anesthesia and physiological parameters (e.g., BP, HR, RR, ET agent concentration) outputted from the anesthesia monitor will be recorded electronically during the surgery by the anesthesia monitoring system (data-points will be recorded at least every 3 min for BP and every 10 sec for other variables). The EEG signal will be continuously recorded by NeuroSENSE NS-701 Monitor (described under a separate intervention). The CRC will also be present in the Operating Room (OR) to record and manage the recording of all the required information.

OTHER

Drug: Emergence by stepping down the desflurane ET

Anesthesia will be reduced to facilitate rapid recovery at the discretion of the anesthesiologist, about 20 minutes before the end of surgery. The desflurane ET will be stepped down from 0.8 MAC by steps of 0.2 MAC approximately every 5 min during the Emergence.

Sponsors & Collaborators

• U.S. Army Medical Research Acquisition Activity

  collaborator FED

• Fraser Health

  collaborator OTHER

• NeuroWave Systems Inc.

  lead INDUSTRY

Principal Investigators

• Richard Merchant, MD FRCPC · Fraser Health

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2014-06-30

Primary Completion

2014-12-31

Completion

2016-10-31

FDA Device

Yes

Countries

• Canada

Study Locations