the Analgesic Duration of Dexmedetomidine Compared to Dexamethasone as Adjuncts to Single Shot Interscalene Block

Currently, the most commonly employed adjunct to peripheral nerve blockade is perineural
dexamethasone. In general, at the doses used in regional anesthesia, dexamethasone has a
minimal side effect profile. However, while it has been shown to increase duration of
analgesia, there have been concerns regarding its neurotoxicity in animal studies. In
addition, dexamethasone has the potential to cause hyperglycemia in patients with impaired
glucose metabolism as well as perineal pain and pruritis when administered peripherally.

Dexmedetomidine is a highly selective alpha-2 agonist that is commonly used in patients
undergoing anesthesia or requiring sedation in a non-operative setting. As a peripherally
administered medication, it has both sedating and analgesic properties, as well as the added
benefit of avoidance of respiratory depression. Although it can rarely produce cardiac
depression at high doses, its side effect profile is otherwise minimal and is generally very
well tolerated by most patients. When administered peripherally, dexmedetomidine has most
commonly been associated with side effects such as hypotension, respiratory depression, and
bradycardia - although all at significantly higher doses than planned in our study. The safe
use of perineural dexmedetomidine together with local anesthetics has been described on
numerous occasions. Nevertheless, although it has been shown to potentiate peripheral nerve
blockade and prolong duration of analgesia in various studies , it remains rarely used as an
adjunct to regional anesthesia.

Inclusion Criteria :

- ASA 1 and 2

- 18-60 years old

- Patients scheduled for ambulatory arthroscopic or open surgery

Exclusion Criteria:

- ASA 3 and 4

- Pre-existing pain disorder

- Regular consumption of chronic pain medication

- Anatomical abnormalities of upper extremity

- Known allergy or hypersensitivity to Ropivacaine or other amide local anesthetics

- Known allergy to dexmedetomidine

- Coagulopathy

- Uncontrolled Diabetes