This study was a randomized controlled clinical trial that was conducted in the otolaryngology department of * University of Medical Sciences in 2023. The participants were 40 patients, who were candidates for tympanoplasty using the posterior ear incision method. The data collection tool included a checklist designed by the researchers and according to the research variables, including age, sex, BDT, duration of surgery, complications, drug consumption, surgeon satisfaction level and success of the operation.
Inclusion criteria: Age 18 to 61 years, no history of bleeding disorders and abnormal coagulation tests (PT, PTT, INR BT, CT, platelet count), no history of thromboembolic events and heart failure/acute or chronic kidney disease, not taking anticoagulant drugs up to five days before surgery, not having liver cirrhosis/neuromuscular diseases, not being pregnant, cardiac arrhythmia.
Exclusion criterial: Allergy to D and MS, occurrence of complications during surgery or anesthesia that require special measures, patients requiring bone reconstruction, mastoidectomy and having any pathology in the middle ear.
Procedures: In this study, patients with chronic otitis media who did not respond to conventional medical treatments and were candidates for tympanoplasty were selected. After signing the research consent form, they underwent pure tone audiometric evaluation, speech reception threshold, speech discrimination score in silence and tympanometry [5]. Their demographic information, findings of clinical examinations and audiological evaluations were recorded in research questionnaires and they divided into two groups by random block method; D and MS recipients {D group was 9 men (45%) and 11 women (55%); MS group was 10 men (50%) and 10 women (50%)}.
The day before CBC surgery, coagulation tests (PT, PTT, INR, BT, CT) were performed for all patients. Induction of anesthesia was standardized for patients with intubation and infusion of Fentanyl 5–7 µg/kg, Propofol 1–2 mg/kg [7], Midazolam 1/mg/kg, and Atracurium relaxant 5 mg/kg [4]. Fentanyl infusion at the rate of 1–3 µg/kg/h and Propofol infusion at the rate of 100–200 µg/kg/min were used to maintain mean arterial blood pressure (range 60 to 70 mmHg) and anesthesia management. Immediately after induction of anesthesia, in the first group D was injected intravenously with a dose of 1 µg/kg for 15 minutes and in the second group MS with a dose of 40 mg/kg.
Mean arterial blood pressure was recorded before the start of surgery and then the work was started by a surgical team. During surgery, according to BDT and patient weight, normal saline serum was prescribed. The volume of BDT was measured according to the amount of blood collected in the suction bottle, and after subtracting the volume of normal saline serum, the mean arterial blood pressure was recorded. At the end of the operation, the duration of surgery, the degree of satisfaction of the surgeon and the duration of anesthesia of the patient were recorded. Three months after the operation, the success rate of tympanoplasty was checked.
Randomization method: The randomization method was based on block randomization using ABAB quadruple blocks. A table containing 4 rows and 10 columns, where two letters A and two letters B (one letter per house) are randomly placed in each row. Patients were divided into two groups, D or MS, according to the type of letter in the cell, each letter was removed after selection.
Blinding method: This study was conducted in a double-blind manner. The syringe of drugs of group D and MS only had a code of one of the letters A or B on which the name of the drug was written. Only one of the operating room personnel who was responsible for coding and writing them on the syringe knew about this. Until the end of the investigation, the surgeon, patient and other operators were unaware.
Limitations of the research: It was the lack of trust and cooperation of the patients, which was resolved by the project manager with reassurance and proper explanation.
Ethical Considerations: This study was approved by the ethics committee of ***University of Medical Sciences. The participants were informed about the side effects of the drugs and written consent was obtained from them. The tests and examinations used in this study were among the common diagnostic and treatment processes of patients and no extra cost was imposed on them. Patients were assured that the results of the study would be published anonymously. This study hindered their diagnostic and therapeutic measures and they were allowed to withdraw from the research at any stage of the work.