Conditions: Anesthesia, Local Shoulder Surgery
Keywords: ropivacaine bupivacaine glucocorticoid
Allocation: RANDOMIZED | Intervention model: FACTORIAL
Enrollment: 218
Healthy volunteers: no

Brief summary:
This study will test the hypothesis that adding dexamethasone significantly prolongs the duration of ropivacaine and bupivacaine analgesia, and that the magnitude of the effect differs among the two local anaesthetics.. Participants will be patients undergoing shoulder surgery with an interscalene nerve block.

Detailed description:
This is a double-blinded randomized study of four groups of patients undergoing shoulder surgery using interscalene nerve blocks. Participants will be randomized into one of four groups:

* Ropivacaine: 30 ml 0.5% ropivacaine plus 2 ml 0.9% saline (placebo) for interscalene block;
* Bupivacaine: 30 ml 0.5% bupivacaine plus 2 ml 0.9% saline (placebo);
* Ropivacaine and steroid: 30 ml 0.5% ropivacaine plus dexamethasone 8 mg (2 ml) mixed with the local anesthetic;
* Bupivacaine and steroid: 30 ml 0.5% bupivacaine plus dexamethasone 8 mg (2 ml) mixed with the local anesthetic.

The primary outcome is the duration of the interscalene nerve block which is time to first analgesic request after PACU discharge.

Kaplan-Meier survival density estimation and stratified Cox proportional hazard regression were used to compare groups.

Arms:
arm 1: Group 1 Ropivacaine: 30 ml 0.5% ropivacaine plus 2 ml 0.9% saline for interscalene block arm 2: Group 2 Bupivacaine: 30 ml 0.5% bupivacaine plus 2 ml 0.9% saline arm 3: Group 3 Ropivacaine and dexamethasone: 30 ml 0.5% ropivacaine mixed with dexamethasone 8 mg (2 ml) arm 4: Group 4 Bupivacaine and steroid: 30 ml 0.5% bupivacaine mixed with dexamethasone 8 mg (2 ml).

Interventions: intervention 1: saline intervention 2: Dexamethasone intervention 3: ropivacaine intervention 4: Bupivacaine
Intervention descriptions: intervention 1: 2 ml 0.9% saline (placebo) intervention 2: dexamethasone 8 mg (2 ml) intervention 3: 30 ml 0.5% ropivacaine intervention 4: 30 ml 0.5% bupivacaine

Protocol document: