Study: NCT00702416

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Ultrasound-guided continuous interscalene brachial plexus block
Description: With patients in the supine position, a high-frequency (10-12 MHz) ultrasound transducer in a sterile sheath will be applied to explore the interscalene region and locate the brachial plexus. The transducer will be positioned so as to image the C5 and C6 roots in a single view. Visualization of the C7 root in the same scan will be sought, but will not be required.~A 50-mm, 20 G needle will be advanced in-plane from the postero-lateral side of the transducer. Injection of the local anesthetic will be performed in small aliquots while repositioning of the needle in order to optimize spread of the injectate around the nerve roots.~At the end of the injection, a catheter will be threaded through the needle. The catheter will be positioned to lie deep and close to the imaged nerve roots.

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Continuous interscalene brachial plexus block using electrical nerve stimulation
Description: With patients in the supine position, the head will be rotated to the contralateral side. The interscalene groove will be palpated.~A 35-mm, 20 G needle will be inserted at the estimated C6 level (cricoid cartilage) with a 30-45° angle to the skin. The needle will be advanced along a line joining the insertion site to the axilla.~An electrical nerve stimulator will be used at an initial intensity of 1.0 mA (frequency: 2 Hz, pulse width: 0.2 ms). A musculocutaneous or axillary-nerve mediated twitch will be sought~Injection of the local anesthetic will start with a visible motor response at a current \<0.5 mA. The catheter will be positioned to as to elicit a motor response at ≤0.4 mA.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Ropivacaine
Description: Block induction \[1% (wt/vol) solution\]:~20 ml (200 mg)~Postoperative analgesia \[0.2% (wt/vol) solution\]:~* Background infusion: 4 ml/h (8 mg/h)~* Incremental on-demand dose: 2 ml (4 mg)~* Lockout time: 15 min

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Ropivacaine
Description: Block induction \[1% (wt/vol) solution\]:~20 ml (200 mg)~Postoperative analgesia \[0.2% (wt/vol) solution\]:~* Background infusion: 4 ml/h (8 mg/h)~* Incremental on-demand dose: 2 ml (4 mg)~* Lockout time: 15 min

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Paracetamol
Description: 1 g iv q8h

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Paracetamol
Description: 1 g iv q8h

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Morphine
Description: 5 mg im prn q1h (in the postoperative period)

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Morphine
Description: 5 mg im prn q1h (in the postoperative period)

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Fentanyl
Description: 50 µg iv prn (in the intraoperative period)

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Fentanyl
Description: 50 µg iv prn (in the intraoperative period)

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: General anesthesia
Description: Will be given in case of block failure and/or patient discomfort intractable with fentanyl during the procedure.~The technique will be left at the discretion of the attending anesthesiologist. Monitored anesthesia care will also be acceptable; the block will be considered as failed in that case as well.

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: General anesthesia
Description: Will be given in case of block failure and/or patient discomfort intractable with fentanyl during the procedure.~The technique will be left at the discretion of the attending anesthesiologist. Monitored anesthesia care will also be acceptable; the block will be considered as failed in that case as well.