Low-Flow Desflurane Anesthesia and Its Effects on BIS and Postoperative Cognitive Functions

Dolunay ARIK

Status: Active, not recruiting

Conditions: Major Abdominal Surgeries

Treatments: Other: Routine anesthesia care (desflurane at different low-flow rates: 0.5, 1.0, 1.5 L/min); no intervention assigned as part of the study.

Study type: Observational

Funder types: Other

Identifiers

NCT07212543

2025-05/73

Details and patient eligibility

About

This study investigates the effects of low-flow desflurane anesthesia in adult patients undergoing major abdominal surgery. The researchers will examine whether different low-flow strategies:

Cause differences in the Bispectral Index (BIS), which measures brain activity during anesthesia, Affect postoperative cognitive functions such as memory and attention.

Participants will:

Receive desflurane anesthesia during surgery, Have anesthesia delivered at different low-flow rates, Have their BIS values monitored throughout the operation, Complete tests after surgery to evaluate their cognitive functions.

This research will help determine the safety of different low-flow strategies and their impact on patients' cognitive recovery after surgery.

Full description

This prospective observational study is designed to evaluate the effects of different low-flow desflurane anesthesia strategies on intraoperative anesthetic depth, measured by the Bispectral Index (BIS), and on postoperative cognitive functions in patients undergoing major abdominal surgery.

Patients will receive desflurane anesthesia delivered at different low-flow rates. Throughout surgery, BIS values will be continuously monitored to assess the depth of anesthesia. Postoperatively, standardized cognitive function tests will be performed at predetermined time points to evaluate potential cognitive impairment or recovery. The study aims to clarify whether the choice of low-flow strategy influences short-term postoperative neurocognitive outcomes.

Quality assurance and data management procedures:

Data collection will be conducted using standardized electronic case report forms (eCRFs).

All collected data will undergo range and consistency checks against predefined rules.

Source data verification will be performed through comparison with medical records and anesthetic monitoring logs.

A data dictionary will be maintained, documenting each variable, coding standards (e.g., MedDRA where applicable), and reference ranges.

Missing data will be handled according to a predefined plan, with cases flagged as missing, unusable, or inconsistent.

Sample size and statistical plan:

The sample size has been estimated to ensure sufficient statistical power to detect clinically meaningful differences in BIS and postoperative cognitive function scores between different low-flow strategies. Statistical analyses will include descriptive statistics, group comparisons using parametric or non-parametric tests, and regression models where appropriate. A detailed statistical analysis plan has been developed to address both primary and secondary endpoints.

This study will provide evidence regarding the safety and neurocognitive impact of different low-flow desflurane strategies. Findings are expected to support clinical decision-making in optimizing anesthetic management for patients undergoing major abdominal procedures.

Enrollment: 72 patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Patients aged 18-75 years

ASA physical status I-III

Scheduled for elective major abdominal surgery

Provided written informed consent

Normal preoperative neurocognitive function

Exclusion criteria

History of neurological or psychiatric disorders

History of cognitive impairment

Diagnosed hepatic or renal insufficiency

Presence of other systemic diseases contraindicating anesthesia

Trial design

72 participants in 1 patient group

Group 1 :desflurane 0.5 L/min Group 2 :desflurane 1 L/min Group 3 : desflurane 1.5 L/min

Description:

This cohort includes adult patients undergoing major abdominal surgery whose general anesthesia is maintained with desflurane using different low-flow strategies. The main intervention of interest is the variation in fresh gas flow rates. Participants will be divided into three subgroups according to the applied flow rate: 0.5 L/min desflurane anesthesia 1.0 L/min desflurane anesthesia 1.5 L/min desflurane anesthesia During surgery, the depth of anesthesia will be continuously monitored using the Bispectral Index (BIS). Cognitive function will be assessed both preoperatively and postoperatively with the Mini-Mental State Examination (MMSE). This design will allow comparison of the effects of different low-flow strategies on intraoperative BIS values as well as on cognitive function changes before and after surgery.

Treatment:

Other: Routine anesthesia care (desflurane at different low-flow rates: 0.5, 1.0, 1.5 L/min); no intervention assigned as part of the study.