Comparison of the effects of total intravenous anesthesia ( TIVA with propofol) versus inhalational anesthesia (Isufluran) on the incidence of emergence delirium based on gender differences in adults undergoing abdominal surjeries

To compare the effect of two anesthetic maintenance techniques (total intravenous anesthesia with propofol versus inhalational anesthesia with isoflurane) on the incidence and severity of postoperative delirium in adults undergoing abdominal surgery, and to evaluate the modifying role of gender.

Randomized, double‑blind, parallel‑group, superiority clinical trial on 200 patients (100 per group). Randomization will be performed using balanced block randomization with concealed allocation.

Population & Sampling: Adults 18-65 undergoing abdominal surgery at Imam Khomeini Hospital, Ilam. Simple random sampling, stratified by gender. Patients allocated to two equal groups of 100: TIVA (propofol) vs. Inhalational (isoflurane). Blinding: Randomized, double-blind, parallel-group trial. Patients, outcome assessors (delirium via CAM-ICU), and data analysts are blinded to group allocation. An independent anesthesiologist administers the drugs. Setting: Post-Anesthesia Care Unit (PACU), Imam Khomeini Hospital, Ilam.

Inclusion criteria: 1. Age 18-65 and abdominal surgery candidate. 2. ASA I or II. 3. No cognitive/psychiatric, hepatic/renal, substance abuse, or drug allergy. Exclusion criteria: 1. Age <18 or >65. 2. ASA ≥III. 3. History of cognitive/psychiatric, hepatic/renal, substance abuse, or drug allergy.

Group 1: total intravenous anesthesia with continuous propofol infusion (100–150 µg/kg/min) and fentanyl. Group 2: inhalational anesthesia with isoflurane (0.8–1.2 MAC) plus fentanyl. Anesthesia induction is identical in both groups using propofol, fentanyl, and atracurium.

Incidence of delirium , severity of delirium , time to extubation, length of stay in the recovery room, hemodynamic changes, and consumption of additional drugs.

Randomization method: Balanced Block Randomization Randomization unit: Individual (each patient is randomized separately) Stratification factors: No stratification is used in this study. Randomization tool: Random number table Sequence generation: Blocks with different permutations including (ABBA, ABAB, AABB, BBAA, BABA, BAAB) are created, where A represents the TIVA with propofol group and B represents the isoflurane group. Then, based on a random number table, the allocation sequence is determined to maintain group balance and blinding. Allocation concealment: The study drugs (propofol solution and isoflurane liquid) are prepared in identical containers without any label indicating the group and are provided to the anesthesiologist. Only the principal investigator has access to the randomization codes.

This study uses a double-blind design. Blinding is implemented as follows: 1. Participants (Patients): Patients receive complete information about the study one day before surgery but are unaware of the type of anesthesia method assigned to them. 2. Anesthesiologist (Intervention provider): Although the anesthesiologist is aware of the administered drug, all drugs are prepared in identical containers without any group-identifying labels to minimize selection bias. 3. Surgeon: The surgeon is blinded to the anesthesia method. 4. Recovery room nurses (Clinical caregivers): Nurses responsible for patient care and assessment in the post-anesthesia care unit (PACU) are blinded to the group allocation. 5. Outcome assessors: Trained nurses who administer the CAM-ICU and CAM questionnaires for delirium assessment are completely blinded to the patients' group allocation. 6. Principal investigator: The principal investigator has access to the randomization codes but is not involved in outcome assessment. However, the codes will be used for final data analysis. 7. Data analyst: The individual performing statistical analysis is blinded to group allocation to prevent bias in data interpretation. 8. Allocation concealment: Study drugs (propofol solution and isoflurane liquid) are prepared in identical containers without any group-identifying labels and are provided to the anesthesiologist. Only the principal investigator has access to the randomization codes and is not involved in drug administration.

Individual Participant Data (IPD) from a randomized clinical trial comparing TIVA with propofol versus isoflurane on emergence delirium in abdominal surgery

Data will be available after publication of the main results (expected 12 months after study completion) and will remain accessible for 5 years.

Qualified researchers from academic institutions with a valid research proposal and ethics approval, upon reasonable request to the corresponding author (Atieh Zolfaghari, zola69440@gmail.com)

The de-identified IPD and supporting documents (protocol, SAP, data dictionary) may be used exclusively for: (1) secondary analyses related to postoperative cognitive outcomes, delirium, or anesthetic techniques; (2) systematic reviews and meta-analyses; (3) methodological validation or replication studies. Users must not use the data for commercial purposes, must maintain confidentiality, and must cite the original study in any resulting publications. Any secondary analysis must be approved by the corresponding author and the ethics committee of the user's institution.

Requests for data and supporting documents should be directed to the corresponding author: Atieh Zolfaghari, Department of Anesthesiology, Ilam University of Medical Sciences, Ilam, Iran. Email: zola69440@gmail.com. Postal address: Ilam University of Medical Sciences, Ilam, Iran. Telephone: +98-9964871066.

The request process includes the following steps: (1) The applicant submits a formal request via email to the corresponding author, including a brief research proposal, intended analysis plan, and ethics approval from their institution. (2) The request is reviewed by the research team for scientific validity and ethical compliance. (3) If approved, the applicant signs a data-sharing agreement ensuring confidentiality, non-commercial use, and proper citation. (4) The de-identified data and relevant documents are shared via a secure online repository (e.g., Zenodo or Figshare) with a password-protected link. The entire process is expected to take approximately 2-4 weeks.

This study is registered in the Iranian Registry of Clinical Trials (IRCT). The full protocol and SAP are available as supplementary materials in the main publication. Any publications using these data should cite the primary study and acknowledge the funding source (Ilam University of Medical Sciences).