An observational study in Cardiopulmonary Bypass, Hypothermia; Anesthesia and Depth of Anesthesia Monitoring, sponsored by Sakarya University. Active, not recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-02.
Sponsored by Sakarya University · Observational
The goal of this observational study is to evaluate whether hypothermia affects the relationship between electroencephalography-derived indices during cardiac surgery in adult patients undergoing cardiopulmonary bypass.
The main questions it aims to answer are:
Does the correlation between Bispectral Index (BIS) and Patient State Index (PSI) change between normothermic and hypothermic phases during cardiopulmonary bypass? How do BIS and PSI values change in response to decreasing body temperature?
Participants will:
Undergo standard general anesthesia for elective on-pump coronary artery bypass surgery Be monitored simultaneously with BIS and PSI devices during surgery Have data recorded at predefined temperature-based time points during cardiopulmonary bypass
Hypothermia during cardiopulmonary bypass (CPB) is known to influence cerebral metabolism and electroencephalographic activity. Processed electroencephalography-derived indices such as the Bispectral Index (BIS) and Patient State Index (PSI) are commonly used to monitor anesthetic depth; however, these indices are generated using different proprietary algorithms. While previous studies have demonstrated moderate to high correlation between BIS and PSI under normothermic conditions, it remains unclear whether this relationship is preserved during hypothermic CPB.
This prospective observational study aims to evaluate the effect of hypothermia on the relationship between BIS and PSI in adult patients undergoing elective on-pump coronary artery bypass grafting. Both indices will be monitored simultaneously throughout the intraoperative period using standard sensor placement.
Data will be collected at predefined time points representing normothermic, hypothermic, and rewarming phases of CPB. The primary analysis will focus on comparing the correlation between BIS and PSI at a normothermic reference point (36°C) and a hypothermic reference point (32°C).
To minimize confounding effects, anesthetic management and physiological parameters will be maintained within routine clinical target ranges, and relevant variables will be recorded throughout the procedure. Secondary analyses will explore temperature-dependent changes in each index and agreement between clinically relevant depth-of-anesthesia categories.
This study is designed to clarify whether hypothermia alters the relationship between commonly used processed EEG indices, which may have implications for intraoperative neuromonitoring and anesthetic management during cardiac surgery.
499 studies on the registry are indexed under Hypothermia; 54 are open to participants now.
This study's planned enrollment of 60 is below the median of 97 across 126 observational studies indexed under Hypothermia.
Browse Hypothermia studies →Sakarya University is the lead sponsor of 178 studies on the registry; 48 are open to participants now.
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Adult patients undergoing elective on-pump coronary artery bypass grafting (CABG) with cardiopulmonary bypass at a single tertiary care center will be included. All participants will receive standard general anesthesia and perioperative management according to institutional protocols. Patients will be monitored intraoperatively with both Bispectral Index (BIS) and Patient State Index (PSI) devices, and data will be collected at predefined time points during normothermic, hypothermic, and rewarming phases of cardiopulmonary bypass.
Exclusion Criteria:
Adult patients undergoing elective on-pump coronary artery bypass grafting with cardiopulmonary bypass will be included. All participants will receive standard general anesthesia and intraoperative management according to institutional protocols. Bispectral Index (BIS) and Patient State Index (PSI) will be monitored simultaneously throughout surgery. Data will be collected at predefined time points across normothermic, hypothermic, and rewarming phases of cardiopulmonary bypass to evaluate the relationship between these indices under varying temperature conditions.
Other: Simultaneous BIS and PSI Monitoring
This observational study does not involve any experimental intervention. All participants will receive standard anesthesia and surgical care according to institutional protocols. The study focuses on simultaneous intraoperative monitoring using Bispectral Index (BIS) and Patient State Index (PSI) devices. Sensors for both monitors will be applied prior to induction of anesthesia, and values will be recorded at predefined time points during normothermic, hypothermic, and rewarming phases of cardiopulmonary bypass. No changes will be made to routine clinical management, and all treatments will be determined by the attending anesthesiologist.
Difference in Correlation Between Bispectral Index (BIS) and Patient State Index (PSI) Under Normothermic and Hypothermic Conditions
The primary outcome is the difference in Pearson correlation coefficients between BIS and PSI measured at predefined normothermic (36°C) and hypothermic (32°C) phases during cardiopulmonary bypass. Correlation coefficients will be calculated separately for each phase and compared using Fisher z-transformation to determine whether hypothermia alters the relationship between these indices.
Time frame: Intraoperative (during cardiopulmonary bypass at predefined time points)
Change in Bispectral Index (BIS) and Patient State Index (PSI) per Degree Celsius During Cooling and Rewarming
This outcome evaluates temperature-dependent changes in BIS and PSI during cooling and rewarming phases of cardiopulmonary bypass. The rate of change in each index per degree Celsius (Δindex/°C) will be calculated using repeated measurements across predefined temperature points. Linear mixed-effects models will be used to estimate the relationship between core temperature and index values while accounting for within-subject variability.
Time frame: Intraoperative (during cooling and rewarming phases of cardiopulmonary bypass)
Effect of CPB Initiation on the Relationship Between Bispectral Index (BIS) and Patient State Index (PSI)
This outcome assesses the impact of cardiopulmonary bypass initiation on the relationship between BIS and PSI. Pearson correlation coefficients will be calculated at the pre-CPB stable normothermic time point (T4) and after CPB initiation under normothermic conditions (T5). The change in correlation between these two time points will be evaluated to determine whether initiation of CPB alters the association between the indices.
Time frame: Intraoperative (comparison of pre-CPB and post-CPB initiation time points)
Agreement in Clinical Depth Categories Between Bispectral Index (BIS) and Patient State Index (PSI)
This outcome evaluates the agreement between BIS and PSI when classified into clinically relevant depth-of-anesthesia categories. BIS values will be categorized as \>60 (light), 40-60 (adequate), and \<40 (deep), while PSI values will be categorized as \>50 (light), 25-50 (adequate), and \<25 (deep). Agreement between the two indices will be assessed using Cohen's kappa coefficient. Comparisons will be performed separately for normothermic and hypothermic phases to determine whether temperature affects categorical agreement.
Time frame: Intraoperative (during predefined normothermic and hypothermic phases of cardiopulmonary bypass)
Plan to share: Undecided — Individual participant data may be shared upon reasonable request, subject to approval by the institutional ethics committee and in accordance with applicable data protection regulations. At the time of registration, a definitive data sharing plan has not been finalized.
This study is active, not recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Sakarya University