Source: Ilfeld et al, Anesth 2002;96:1297-1304

Reviewer:  R. Prasad, MD

Summary:

• randomized, double-blinded, placebo-controlled
• ropivacaine infusion using a portable, mechanical pump and an infraclavicular brachial plexus perineural catheter at home decreased pain, sleep disturbances, narcotic use and related side effects, and improved overall satisfaction.

• I do prefer this coracoid approach - I hardly do axillary blocks anymore!
• However, the perpendicular angle made it hard to thread the catheter: they had a pretty high (33%) intravascular catheter rate until they changed technique (0%). They note that they have used the modified technique in 60 catheters without any additional intravascular placements.
• They did not evaluate the success of the initial block. But if there were failures or inadequate blocks, you would expect a smaller difference between groups; so the results are still significant.
• Other studies have shown highly variable patient needs ... I'm sure someone will look at other combinations of infusion rates and bolus doses to maximize pain relief while minimizing local anesthetic dose and risk of side effects. I'd like to see a study using a long-acting initial blockade followed by low rate PCRA starting about 10 hours after block placement.

• 30 patients, 15 per group (calculated for 80% power with p<0.05 to detect difference in POD#1 "worst pain with movement" VAS of 2 btwn groups, with SD 2).
• randomized, double-blinded, placebo-controlled
• preop: coracoid approach infraclavicular nerve block via catheter (50 ml 1.5% mepivacaine with bicarb, epi, and clonidine 100 mcg).
• Cath threaded 3 cm past needle
• After 5 of first 15 attempts were intravascular, changed technique: if resistance noted at end of needle, cath left at needle tip, needle pulled back about halfway, then cath advanced addtl 5cm (5cm slack btwn skin and brachial plexus).
• postop: cath injected with saline/epi to r/o intravascular placement. Discharged home with oral narcotics and a portable infusion pump
• 0.2% ropivacaine vs 0.9% saline
• 2 days therapy
• 1 addtl day follow-up
• Settings: 8 ml/hr, with 2 ml q20min PCRA bolus. If needed to give >1 PCRA bolus q2hr on POD#1, gtt increased to 9.9 ml/hr (pump max).
• Pts given extensive instructions, phone numbers to try to ensure safety
• Daily end points:  pain scores at rest and with limb movement, narcotic use and side effects, sleep quality, patient satisfaction, and symptoms of catheter- or local anesthetic-related complications.

• 35 enrolled, 5 excluded (intravascular catheters found at insertion)
• Ropivacaine vs. Saline:
• less pain (VAS 0-10) - data presented mostly in figures; some numbers available:
• during rest
• with movement POD#1: 2.5 ± 1.6 vs 6.1 ± 2.3
• less oral narcotic use
• POD#1 mean tablet consumption 1.7 ± 1.6 vs 5.5 ± 2.4
• fewer opioid side effects
• fewer sleep disturbances (difficulty sleeping or awakening due to pain)
• overall satisfaction greater: 9.2 ± 1.1 vs 5.8 ± 3.0
• No catheter- or local anesthetic-related complications.