Intraoperative AwarenessNCT07831590
Evaluation of Intraoperative Awareness and Its Correlation With Processed EEG Biomarkers During Laparoscopic Surgery
An observational study of Intraoperative Awareness and Intraoperative Responsiveness During General Anesthesia, run by Duzce University at 1 site in Turkey (Türkiye).
Trial summary
This prospective observational cohort study aims to evaluate intraoperative responsiveness and possible intraoperative awareness in adult patients undergoing elective laparoscopic abdominal surgery under general anesthesia and to investigate their relationship with processed electroencephalography (EEG) biomarkers. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Intraoperative Awareness, Intraoperative Responsiveness During General Anesthesia
- How many people
- 600 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Feb 2026to 1 May 2027
- Phase
- Observational
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will consist of adult patients aged 18 years or older who are scheduled for elective laparoscopic abdominal surgery under general anesthesia. Patients who meet the predefined inclusion criteria and do not meet any exclusion criteria will be prospectively enrolled. The planned sample size is approximately 600 participants.
Who may be able to join
- Age ≥18 years
- Elective laparoscopic abdominal surgery planned
- General anesthesia planned
- Ability to communicate adequately
- Adequate cognitive capacity to understand and respond to study procedures
- ASA physical status I-III
Who cannot join
- Previous cerebrovascular disease
- Psychiatric disorders
- Cognitive dysfunction
- ASA physical status >III
- High frailty
- Body mass index >30 kg/m²
- Pregnancy
- Age <18 years
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Duzce University
Düzce
duzce university, 08502598181, tucetin4705@hotmail.com
About this study
Official title: Evaluation of Intraoperative Awareness During Laparoscopic Abdominal Surgery and Its Correlation With Processed Electroencephalography Biomarkers
This prospective observational cohort study aims to evaluate intraoperative responsiveness and possible intraoperative awareness in adult patients undergoing elective laparoscopic abdominal surgery under general anesthesia and to investigate their relationship with processed electroencephalography (EEG) biomarkers.
Approximately 600 patients will be enrolled. Preoperative assessment will include the 15-item Quality of Recovery questionnaire (QoR-15), State-Trait Anxiety Inventory (STAI), Mini-Mental State Examination (MMSE), and Beck Anxiety Inventory (BAI).
Read more
Processed EEG monitoring will be performed using the Masimo SedLine system. The system will be applied before induction of general anesthesia and maintained throughout the anesthetic period until extubation. Patient State Index (PSI) values will be recorded at 5-minute intervals from the beginning of surgery until extubation.
The isolated forearm technique (IFT) will be performed five times during predefined stages of anesthesia and surgery. The fifth assessment will be performed at any stage of surgery when there is clinical or processed EEG evidence suggesting possible awakening, including a PSI value above 50 and/or accompanying hemodynamic changes such as tachycardia or hypertension.
Postoperative assessment will be performed at the 24th postoperative hour and at the second postoperative week. At 24 hours, QoR-15 and structured awareness questioning will be performed. At two weeks, QoR-15, Beck Anxiety Inventory, dream recall, and further assessment of possible intraoperative awareness will be performed.
The study will investigate the relationship between PSI changes, isolated forearm technique responses, and postoperative reports suggestive of intraoperative awareness.
Read the detailed description
: Intraoperative awareness is a clinically important complication of general anesthesia in which patients may experience consciousness and subsequently recall events occurring during anesthesia. Intraoperative responsiveness and postoperative explicit recall represent related but distinct aspects of consciousness during general anesthesia.
This prospective observational cohort study will include adult patients undergoing elective laparoscopic abdominal surgery under general anesthesia. Approximately 600 participants will be prospectively enrolled.
Before surgery, participants will undergo baseline assessment using the QoR-15, State-Trait Anxiety Inventory, Mini-Mental State Examination, and Beck Anxiety Inventory.
Processed EEG monitoring will be performed using the Masimo SedLine system. The SedLine system will be applied before induction of general anesthesia and maintained throughout the anesthetic period until extubation. PSI values will be recorded at 5-minute intervals from the beginning of surgery until extubation.
The isolated forearm technique will be used to assess intraoperative responsiveness. The first four IFT assessments will be performed at predefined stages during induction and surgery. A fifth IFT assessment will be performed when the clinical course or monitoring suggests possible awakening, including a PSI value above 50 and/or hemodynamic findings such as tachycardia or hypertension. During the IFT, patients will be instructed to respond to a predefined verbal command, and the presence or absence of a response will be recorded.
PSI values corresponding to IFT assessments will be evaluated. Particular attention will be given to increases in PSI associated with positive IFT responses. A positive IFT response together with an increase in PSI will be considered evidence of intraoperative responsiveness and possible intraoperative awareness rather than definitive proof of explicit postoperative awareness.
At the 24th postoperative hour, patients will undergo QoR-15 assessment and structured questioning regarding possible intraoperative awareness and recall. At the second postoperative week, QoR-15 and Beck Anxiety Inventory assessments will be repeated, and dream recall and possible intraoperative awareness will be assessed.
The study will investigate the relationship between processed EEG-derived PSI values, intraoperative responsiveness detected by the isolated forearm technique, and postoperative reports suggestive of awareness. It will also evaluate associations between possible intraoperative awareness and postoperative quality of recovery, anxiety, and dream recall.
- Keywords
- Intraoperative awareness, Awareness during general anesthesia, Intraoperative responsiveness, Patient State Index; Processed EEG; SedLine, Isolated forearm technique
- Medical subject headings
- Intraoperative Awareness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| type 0 | Unconscious No signal; No response to commands No recall No recall Adequate anesthesia | |
| type1 | Intraoperative awareness Signal present Responds to commands No recall No recall or emotional consequences Wakefulness during surgery, erased explicit and implicit memory | |
| type2 | Intraoperative awareness (Cue words provided) Signal present Responds to commands No explicit recall, Implicit memory for provided words No explicit recall; Implicit memory for provided words but no emotional consequences Wakefulness during surgery and subsequent implicit memory | |
| type3 | Intraoperative awareness Signal present Responds to commands No recall PTSD/nightmares present but no explicit memory Wakefulness during surgery and implicit emotional memory | |
| type4 | Intraoperative awareness Signal present Responds to commands Explicit recall with or without pain Explicit memory present but no emotional consequences Awareness present but resilient patient (no emotional damage) | |
| type5 | Intraoperative awareness Signal present Responds to commands Explicit recall accompanied by distress and/or pain Explicit memory with PTSD/nightmares Awareness with emotional damage |
What is being measured
The primary outcome is the main question the study is designed to answer.
Association Between Positive Isolated Forearm Technique Responses and Patient State Index Changes
The primary outcome is the association between positive responses obtained using the isolated forearm technique and changes in Patient State Index (PSI) values during general anesthesia. PSI values will be recorded at 5-minute intervals from the beginning of surgery until extubation. PSI changes occurring during or immediately surrounding positive IFT responses will be evaluated.
Measured: From the beginning of surgery until extubation
Secondary outcomes (9)
. Intraoperative Responsiveness
Frequency of positive isolated forearm technique responses during general anesthesia.
Measured: During induction and surgery.
. PSI Increase Associated With IFT Positivity
Magnitude of PSI increase associated with positive isolated forearm technique responses compared with preceding PSI measurements
Measured: During surgery
Postoperative Awareness at 24 Hours
Patient-reported recall or experiences suggestive of intraoperative awareness assessed by structured postoperative questioning.
Measured: 24 hours after surgery.
Postoperative Awareness at 2 Weeks
Patient-reported recall or experiences suggestive of intraoperative awareness assessed at the second postoperative week.
Measured: 2 weeks after surgery
Quality of Recovery
Change in QoR-15 score from the preoperative assessment to 24 hours and 2 weeks after surgery.
Measured: Preoperatively, 24 hours postoperatively, and 2 weeks postoperatively.
Postoperative Anxiety
Change in Beck Anxiety Inventory score from the preoperative assessment to the second postoperative week and its association with possible intraoperative awareness.
Measured: Preoperatively and 2 weeks postoperatively.
Dream Recall
Presence of dream recall and its association with possible intraoperative awareness.
Measured: 2 weeks after surgery
Preoperative Anxiety
Preoperative state and trait anxiety levels assessed using the State-Trait Anxiety Inventory
Measured: Preoperatively
Cognitive Status
: Preoperative cognitive status assessed using the Mini-Mental State Examination
Measured: Preoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2026
- Study start1 Feb 2026
- Primary completion1 Mar 2027 (estimated)
- Study completion1 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Intraoperative AwarenessStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 600 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Duzce University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07831590
- Sponsor's protocol ID
- 2026/35
- Status last verified
- Sep 2026
- First submitted
- 15 Sep 2026
- Last updated
- 21 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: In accordance with the Law on the Protection of Personal Data, patient data is not publicly accessible; it can be provided upon request.