Comparison of the effects of intravenous dexmedetomidine and the local perineural combination of dexmedetomidine and ropivacaine on the duration of interscalene block and hemodynamic parameters in patients undergoing shoulder surgery

Comparison of the effects of intravenous dexmedetomidine and the local perineural combination of dexmedetomidine and ropivacaine on the duration of interscalene block and hemodynamic parameters in patients undergoing shoulder surgery

The clinical trial study is single-blinded and randomized. After the patients are assigned to the study groups, all patients are similarly went under general anesthesia. At the end of the procedure and before the patient is reversed, an interscalene block is performed according to the defined pattern. To perform the interscalene block, a 5 cm needle No. 22 (B. Brown Medical Company, USA) is inserted under ultrasound guidance in an out-of-plane approach and advanced until the needle tip is adjacent to the C5 and C6 roots. The prepared drug is injected at this location.

The study will be conducted at Shariati and Imam Khomeini Hospitals of Tehran University of Medical Sciences. The study is single-blinded and blinding is only in patients who are unaware of the perineurally injected substance.

Inclusion criteria: Patients age between 18 to 75 years old Patients undergoing elective shoulder surgery Patients with ASA class one and two Exclusion criteria: Known Allergy to local anesthetic drugs Presence any kinds of neurologic, vascular and neuromuscular diseases Presence of hematologic and coagulation abnormalities Chronic opioid usage

First intervention group: dexmedetomidine injection 0.5mcg/kg with 30cc of ropivacaine 0.5% perineural Second intervention group: intravenous dexmedetomidine injection 0.5mcg/kg with 30cc of ropivacaine 0.5% perineural Control group: ropivacaine 0.5% perineural injection

After the intervention, patients are evaluated for the success of the motor block and hemodynamic changes.

Patients will be divided equally into 2 groups using the Block Randomization method. In this way, the treatment order was determined from the different states of the 4-blocks (AABB, ABAB, BBAA, BABA, BAAB, ABBA) randomly using a random number table and the placement of the 4-blocks in each list in such a way that there are no structural differences in the medical and demographic records of the patients in the groups.

Patients participating in the study are informed about the drug injection during the interscalene block, and these patients are blinded to the type of drug injected during the interscalene block. The researcher is fully aware of the type of substance injected into each patient and is not blinded.

Study data can be shared after being de-identified.

Use of study data will be available for at least one year after publication of study results.

All anesthesiologists and pain specialists will have access to the data.

Data analysis and use of results by orthopedic specialists will also be available.

To access the database, please contact the person responsible for the study, Dr. Hamed Abdollahi.

The documents and data will be accessible according to the specified timeframe and upon formal request from academic and non-academic research centers.