None listed
Conditions
Brief summary
General anaesthesia is delivered to individuals during an operation to stop them being aware of what is going around them, prevent any pain and immobilise the body so surgery can be carried out safely. Unfortunately, the anaesthetists do not currently have a reliable way of measuring the exact point when an individual's brain becomes unconscious during the surgery. They tend to judge the amount of anaesthetic they give depending on when the average person would lose consciousness. They then increase or decrease the dose for that person depending on how their heart or the lungs react during the operation. This study will look at the EEG of participants and target a specific waveform- called Deltawaves- as a marker of loss of consciousness and inability to form memory. The study aims to show that titrating the anaesthetic to achieve delta is achievable in a busy clinical theatre without delaying surgery. Additionally patients should not be able to respond or recall events when in Delta for the duration of the surgery. The study will also look at vital signs of patients on the trial to make sure this is as stable as is usually seen in current practise.
Interventions
Realtime analysis of Frontal electroencephalogram (EEG) waveform to maximise Delta-wave formation for elective surgery patients having general anaesthesia.
Patients formally consented prior to surgery
Frontal stickers attached before surgery- often routine practise.
Subtle titration and adjustment of volume of anaesthetic agents to achieve maximal delta-wave formation during operation.
isolated forearm test (IFT) involving a inflated cuff on the arm twice to check for loss of consciousness- a
Realtime analysis of Frontal electroencephalogram (EEG) waveform to maximise Delta-wave formation for elective surgery patients having general anaesthesia. Patients formally consented prior to surgery Frontal stickers attached before surgery- often routine practise. Subtle titration and adjustment of volume of anaesthetic agents to achieve maximal delta-wave formation during operation. isolated forearm test (IFT) involving a inflated cuff on the arm twice to check for loss of consciousness- after induction and after first incision. Researcher in theatre reviewing EEG. Research assistant helping with EEG capture and IFT Research co-ordinator in theatre for blood sampling in the first 20 patients to measure anaesthetic and analgesic levels. quality of recovery measurements and awareness questionnaire in recovery room. Subtle refinements of anaesthetic delivery compared to usual practise only. The expected variation in anaesthetic amounts compared to usual practise is estimated at 10% less to 20% more. The study will not lengthen the anaesthetic time for the participant. Anaesthesia will be conducted using standard, commonly used, drug combinations: midazolam, fentanyl, propofol, sevoflurane, +/- muscle relaxants, +/-anti-nausea drugs, +/-vasopressors. Adjunctive drugs will also be allowed as per the clinician’s judgement: dexmedetomidine, lignocaine, and ketamine in analgesic doses. Anaesthesia will be induced using fentanyl and propofol as per the discretion of the clinician, and then converted to sevoflurane or propofol for maintenance of anaesthesia A person from the research team will be present for each anaesthetic/operation to review the EEG waveform to aid in adherence to protocol.
Sponsors
Waikato District health Board
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
Adult patients (18-90years) presenting for routine surgery under general anaesthesia
Exclusion criteria
Operations on head that would preclude placement of EEG. Inability to give informed study consent for any reason Moribund patients not expected to survive 24 hours, or those needing planned postoperative ICU admission.
Outcome results
None listed