Conditions: Post-operative Pain
Keywords: Peripheral Nerve Infusion, continuous brachial plexus block, post-operative pain diaphragmatic paresis
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 36
Healthy volunteers: no

Brief summary:
Objective: To determine a minimally effective initial local anesthetic bolus required to provide satisfactory analgesia using continuous brachial plexus infusion following arthroscopic shoulder surgery using a double-blind, randomized, study comparing 3 initial doses.

Detailed description:
Aims:

1. To compare pain ratings and supplemental analgesic requirements at discharge from PACU, 24 hours, and 48 hours and 12 weeks following 5, 10, and 20 ml boluses.
2. To compare adverse events including clinical dysphonia, Horner's syndrome, dyspnea, unexpected hospitalization, evidence of local anesthetic toxicity, and hand weakness at discharge from PACU following 5, 10, and 20 ml boluses.
3. To compare impairment in diaphragmatic excursion at discharge from PACU following 5, 10, and 20 ml boluses.
4. To compare patients' satisfaction with analgesia at 24 and 48 hours following 5, 10, and 20 ml boluses.
5. To compare patient rating of functional outcome at baseline and at 12 weeks following 5, 10, and 20 ml boluses.
6. To compare the rate of general anesthesia required following 5, 10, and 20 ml boluses.

Arms:
arm 1: Initial Bolus 5 ml Ropivacaine arm 2: Initial Bolus 10 ml Ropivacaine arm 3: Initial Bolus 20 ml Ropivacaine

Interventions: intervention 1: Ropivacaine intervention 2: Ropivacaine intervention 3: Ropivacaine
Intervention descriptions: intervention 1: Initial Bolus 5 ml Ropivacaine via interscalene injection intervention 2: Initial Bolus 10 ml Ropivacaine via interscalene injection intervention 3: Initial Bolus 20 ml Ropivacaine via interscalene injection

Protocol document: