Comparison of the Incidence of Postoperative Delirium in Elderly Patients Over 60 Undergoing Knee Arthroplasty with General Anesthesia Using Propofol or Dexmedetomidine.

Comparison of the Incidence of Postoperative Delirium in Elderly Patients Over 60 Undergoing Knee Arthroplasty with General Anesthesia Using Propofol or Dexmedetomidine

The present study is a double‑blind, randomized clinical trial with parallel groups (using block randomization), conducted on a total of 146 patients.

In this double-blind, randomized clinical trial, elderly patients over 60 years old scheduled for knee replacement surgery under general anesthesia at Vali Asr Hospital, Arak, will be randomly assigned to two groups (A and B) using block randomization. Blinding will be achieved through syringe labeling of the drugs and patient coding, and the study outcomes will be compared between the two groups.

Inclusion criteria: Patients scheduled for knee joint replacement surgery under general anesthesia; those who have provided informed consent to participate in the study; surgery duration between 60 to 150 minutes. Exclusion criteria: Presence of systemic or specific diseases such as kidney, liver, cardiovascular diseases, hypertension, diabetes, psychiatric and psychotic disorders, Parkinson’s disease, motion sickness, history of chemotherapy, and malignancies; history of substance abuse, chronic analgesic use, allergy to the study drugs, and seasonal allergies.

Dexmedetomidine group: Patients in this group will receive dexmedetomidine (0.1 mcg/kg per hour) via infusion from the induction of anesthesia until recovery room admission. Propofol group: Patients in this group will receive propofol (100 mcg/kg per minute) via infusion from the induction of anesthesia until recovery room admission.

Incidence of delirium, duration of delirium, onset time of delirium, mean arterial pressure, heart rate, and arterial oxygen saturation.

Participants will be allocated to two intervention groups based on their order of entry and according to a randomization sequence that will be generated in advance. This sequence will be unpredictable, and the allocation will be entirely random. Block randomization with blocks of 4 will be used for sample allocation. Using software to generate random numbers in a block design, a randomization sequence will be created according to the required sample size for the two groups. Initially, all possible combinations of the letters A and B within the 4-item blocks will be arranged. Then, one block is randomly selected, and its arrangement will be used for allocating participants. Afterward, this block is placed in the main container, and another block is selected. All these steps will be performed using software called Sealed Envelope. With this method, concealment will also be maintained. The concept of concealment means that the allocation of participants to groups is unpredictable. In practice, the researcher will not be able to predict which group the next participant will be assigned to.

This study will be conducted as a double-blind trial. None of the patients will be aware of the type of drug they are receiving. These drugs will be administered by the anesthesiologist, with each drug drawn into a separate syringe. The syringes and the extension tubes connecting the syringes to the angiocatheter will be covered with foil, so the contents will remain unknown. As a result, the intern responsible for recording outcomes will not know the patient group assignment and will assess the patients based on their file numbers, then provide the collected data to the attending physician.

After conducting this study and analytical studies on it, only a part of the data such as information about the main outcome and patient demographic information will be published to the researchers who do the necessary correspondence with the person in charge of this study.

The access period will start on 2026/04/19, and continue until 2029/04/18 for a duration of three years.

University researchers

Academic researchers or university professors or students who intend to use the data of this study, after obtaining permission from the relevant people mentioned, can use the information of this study in the field of metallurgical studies or other relevant review studies. In addition, if requested, they can use the information of this study for the prerequisites of their future studies and the existence of questions and ambiguities. Using the information of this study is subject to mentioning the names and logos of the responsible persons in this study.

University researchers and university professors can request Dr. Ahmadreza Behrouzi to use the data after contacting the relevant professor via message or email. Dr. Hesamuddin Modiri: Phone: 09183615107 Email: modir.he@gmail.com, Address: Valiasr Hospital, Arak, Vice-Chancellor of Hospital Education.

Letter writing should be done with professors and universities.