An observational study in Intraoperative Awareness and Intraoperative Responsiveness During General Anesthesia, sponsored by Duzce University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by Duzce University · Observational
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).
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.
: 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.
55 studies on the registry are indexed under Intraoperative Awareness; 8 are open to participants now.
This study's planned enrollment of 600 is above the median of 120 across 28 observational studies indexed under Intraoperative Awareness.
Browse Intraoperative Awareness studies →Duzce University is the lead sponsor of 76 studies on the registry; 11 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Unconscious No signal; No response to commands No recall No recall Adequate anesthesia
Intraoperative awareness Signal present Responds to commands No recall No recall or emotional consequences Wakefulness during surgery, erased explicit and implicit memory
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
Intraoperative awareness Signal present Responds to commands No recall PTSD/nightmares present but no explicit memory Wakefulness during surgery and implicit emotional memory
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)
Intraoperative awareness Signal present Responds to commands Explicit recall accompanied by distress and/or pain Explicit memory with PTSD/nightmares Awareness with emotional damage
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.
Time frame: From the beginning of surgery until extubation
. Intraoperative Responsiveness
Frequency of positive isolated forearm technique responses during general anesthesia.
Time frame: 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
Time frame: During surgery
Postoperative Awareness at 24 Hours
Patient-reported recall or experiences suggestive of intraoperative awareness assessed by structured postoperative questioning.
Time frame: 24 hours after surgery.
Postoperative Awareness at 2 Weeks
Patient-reported recall or experiences suggestive of intraoperative awareness assessed at the second postoperative week.
Time frame: 2 weeks after surgery
Quality of Recovery
Change in QoR-15 score from the preoperative assessment to 24 hours and 2 weeks after surgery.
Time frame: 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.
Time frame: Preoperatively and 2 weeks postoperatively.
Dream Recall
Presence of dream recall and its association with possible intraoperative awareness.
Time frame: 2 weeks after surgery
Preoperative Anxiety
Preoperative state and trait anxiety levels assessed using the State-Trait Anxiety Inventory
Time frame: Preoperatively
Cognitive Status
: Preoperative cognitive status assessed using the Mini-Mental State Examination
Time frame: Preoperatively
Plan to share: No — In accordance with the Law on the Protection of Personal Data, patient data is not publicly accessible; it can be provided upon request.
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