BIS Variability and Change in Quality of Recovery After Surgery
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Bispectral Index Variability During General Anesthesia and Postoperative Recovery, Cholecystectomy, Laparoscopic. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Turkey (Türkiye)
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Association Between Intraoperative Bispectral Index Variability and Change in Quality of Recovery-15 Score: A Prospective Observational Study
Overview
This prospective observational study aims to examine the relationship between fluctuations in anesthesia depth, measured by bispectral index (BIS) monitoring during surgery, and changes in patients' postoperative recovery quality. BIS monitoring is routinely used during general anesthesia to assess the depth of anesthesia, but BIS values often fluctuate over time rather than remaining stable. The clinical significance of this variability is not well understood. In this study, BIS variability during anesthesia induction and maintenance will be evaluated and compared with changes in postoperative recovery quality. Recovery quality will be assessed using the Quality of Recovery-15 (QoR-15) questionnaire, which will be administered before surgery and again on the first postoperative day. The primary outcome of the study will be the change in QoR-15 score from the preoperative baseline to postoperative day one (ΔQoR-15). Delirium screening and routine perioperative clinical data will also be collected. No additional interventions beyond standard anesthesia care will be performed. The results of this study may help improve understanding of how intraoperative anesthesia stability relates to patient recovery after surgery.
Detailed description
Bispectral index (BIS) monitoring is widely used in routine anesthesia practice to assess anesthetic depth using processed electroencephalographic signals. Although absolute BIS values are commonly targeted during anesthesia, BIS readings frequently exhibit intraoperative fluctuations rather than remaining stable. The clinical relevance of this variability, particularly in relation to postoperative recovery outcomes, remains insufficiently characterized.
This prospective observational study is designed to evaluate the association between intraoperative BIS variability and changes in postoperative recovery quality. Adult patients undergoing elective laparoscopic cholecystectomy under standardized general anesthesia will be included. No experimental intervention or protocol-driven modification of anesthetic management will be applied beyond routine clinical care.
BIS data will be obtained as part of standard anesthesia monitoring and exported from the BIS monitor at the end of each procedure. Only BIS measurements meeting predefined signal quality criteria will be included in the analysis. BIS variability will be quantified using statistical dispersion measures derived from filtered BIS data during predefined anesthesia phases, including induction and maintenance.
Postoperative recovery quality will be assessed using the Quality of Recovery-15 (QoR-15) questionnaire. QoR-15 will be administered preoperatively to establish baseline status and repeated on postoperative day one. The primary outcome will be defined as the change in QoR-15 score from baseline to postoperative day one (ΔQoR-15). Screening for postoperative delirium and routine perioperative clinical variables will be collected as secondary or exploratory outcomes.
Statistical analyses will focus on assessing the association between BIS variability metrics and ΔQoR-15, with additional analyses performed to account for relevant perioperative variables. The findings of this study are expected to contribute to a better understanding of how intraoperative anesthetic stability relates to patient-centered recovery outcomes following surgery.
Primary outcome measures
- Change in Quality of Recovery-15 (ΔQoR-15) Score [Time frame: From preoperative baseline to postoperative day one]
Secondary outcome measures (2)
- Incidence of Postoperative Delirium (Nu-DESC ≥ 2) [Time frame: From preoperative baseline to early postoperative recovery in the post-anesthesia care unit (PACU), within the first 2 hours after anesthesia]
- Postoperative Pain Intensity (VAS) [Time frame: Postoperative day 1]
Eligibility criteria
Inclusion criteria
- Adults aged 18 to 65 years
- Scheduled for elective laparoscopic cholecystectomy
- American Society of Anesthesiologists (ASA) physical status I-III
- Planned general anesthesia with routine bispectral index (BIS) monitoring
- Ability to provide written informed consent
Exclusion criteria
- History of neurological disease
- Use of neuropsychiatric medications
- Cognitive impairment or mental retardation
- Inability to complete the Quality of Recovery-15 (QoR-15) questionnaire
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
Turkey (Türkiye) · 1 center
- Sakarya University Training and Research Hospital, Department of Anesthesiology and Reanim — Sakarya
Identifiers
NCT: NCT07454629 · SEAH-BISVARIABILITY-2026