Chapter 69. Continuous Peripheral Nerve Blocks
Regarding continuous nerve blocks, all of the following statements are true except:
A. The best infusion rate is 5 mL/hr.
B. Typically, a lower concentration of local anesthetics is used (eg, 0.125% bupivacaine).
C. Femoral catheters in mobile patients can become displaced from the therapeutic position after 6 hours in 25% of cases.
D. Most common systems are catheter-through-needle designs.
E. Their clinical efficacy is well-documented in clinical trials.
A is not true, so option A is correct. The best infusion rate is as yet undetermined as there are varying influences that affect infusion rate, eg, anatomic site.
B, C, D and E are incorrect. All of these are true statements regarding continuous peripheral nerve blocks.
Well-documented indications for perineural infusions of local anesthetics through catheters include:
A. Sympathectomy to improve circulation
B. Treatment of Raynaud’s phenomenon
D. Complex regional pain syndrome
A, B, C, and D are all indications for perineural infusions, so option E is correct. The reported indications for perineural infusions of local anesthetics include sympathectomy/vasodilation after vascular accidents or embolism, digit reimplantation, limb salvage, and treatment of Raynaud phenomenon. Continuous infusions have also been described for painful chronic conditions such as phantom limb pain, complex regional pain syndrome, cancer pain, and preoperative pain control.
Of the options below, which is not a well-documented benefit of perineural infusions of local anesthetics through catheters?
A. Control of postoperative pain
B. Decreased use of opioids when treating acute postoperative pain
C. Advancement of physical therapy goals
D. Complete post operative analgesia for knee arthroplasty, via a femoral catheter.
E. Earlier readiness and discharge from the hospital
D is correct. This is not a well-documented benefit of perineural infusions because a femoral catheter does not provide complete postoperative analgesia for knee arthroplasty. Femoral catheters have been studied extensively in the setting of knee arthroplasty, and continuous femoral infusions have been validated with multiple documented in-hospital benefits including improved analgesia and earlier attainment of range-of-motion. However, multiple nerves innervate surgical sites such as the knee ...