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Join the Regional Anesthesia Revolution
Find out how to reduce general anesthesia and improve post-op pain management.
Karen Nielsen
Publish Date: October 10, 2007   |  Tags:   Anesthesia

Here at Duke University ASC, we treat some very challenging outpatient cases. Total joint replacements. Open inguinal hernia and rotator cuff repairs. Mastectomies. What's more, we treat high-risk outpatients, who go home complication-, PONV- and pain-free. How? Advanced regional anesthesia: single-injection and continuous-infusion peripheral nerve blocks. Here are five keys to our success.

Anesthesia- provider training
Most anesthesiology residency programs in the United States don't provide adequate training in peripheral nerve block techniques. However, good one-year regional anesthesia fellowship programs, regional anesthesia workshops and other courses are available. These programs are essential, as proficient providers must master three challenging areas:

  • Anatomy. Providers must have command of the areas served by the various nerves to ensure analgesia to the entire surgical site. Sometimes, two nerves or plexus innervate the surgical area, necessitating multiple blocks. For instance, with total knee arthroplasty patients, we place a primary continuous peripheral nerve block to the lumbar plexus and a secondary block to the sciatic nerve. After 23 hours, we bolus the secondary catheter with local anesthetic, remove it and continue the primary perineural infusion at home for two more days.
  • Pharmacokinetics/pharmacodynamics. Providers must tailor blocks to maximize analgesia, protect function and minimize toxicity. A solid working knowledge of drug properties, including durations of action and toxicity profiles, is essential. We sometimes use long-acting or a combination of short- and long-acting drugs; for example, we may treat a knee scope/meniscus debridement patient with a femoral nerve block using long-acting ropivacaine and a sciatic nerve block using intermediate-acting mepivacaine. This provides excellent anesthesia without over-sedation, yet allows the patient to regain foot sensation three hours to five hours post-op while the quadriceps remain anesthetized. To minimize the CNS and cardiovascular toxicity that can result from systemic absorption of the blocking agent during continuous infusions, the provider must also use the safest possible local anesthetics and tailor them to the surgical site, procedure and patient population.
  • Practical application. Providers must become intimately familiar with anatomic landmarks for locating nerves and interpreting signs of peripheral nerve stimulation - skills that have a significant learning curve. When we first learned to do regional blocks, our incidence of pneumothorax due to missed paravertebral blocks was one in 256 patients; now it's two in 4,500 patients (or two in 18,000 injections).

30,000 Blocks and Counting

Between July 1998 and March, 20,060 patients underwent outpatient procedures under 30,000 peripheral nerve blocks at Duke University ASC. A summary:

' Nearly 3,800 (12.7 percent) were continuous peripheral nerve blocks.

' Nearly one-fifth (19.8 percent) of our regional anesthesia patients were ASA 3 and 1.1 percent were ASA 4.

' Ninty-five percent of blocked patients had VAS scores of 0 in the PACU versus 74 percent of general anesthesia patients. Ninty-five percent of patients receiving continuous infusions reported VAS scores of 0, and none reported a score greater than 3 at 24 hours.

''Approximately 54 percent of patients who received single-injection peripheral nerve blocks took narcotics after the block wore off during post-op day one. ten percent of patients undergoing continuous peripheral nerve blocks took narcotics during the first 24 hours.

' The acute complication rate is 0.23 percent (see chart). The incidence of long-term complications is rare. There have been no permanent neurologic injuries related to the regional anesthesia techniques.

' More than 95 percent of patients are "very satisfied" with their care after 24 hours.

Acute Block Complications
Duke Ambulatory Surgery Center ? ? ? ? ?July 13, 1998 - March 31, 2004 (n=29,761)

None

29,692

99.77%

Epidural spread

26

0.090%

Pre-seizure excitation

10

0.030%

Seizure

8

0.020%

Hematoma

8

0.020%

Hypotension

7

0.020%

Hypotension

5

0.010%

Pneumothorax

2

0.004%

Subdural block

1

0.003%

Cardiac arrest

1

0.003%

Pleural puncture

1

0.003%

0%

100%

Surgeon acceptance
How do you convince surgeons that regional anesthesia is in the best interest of patients, the surgical team and the facility alike? Clinical data speak volumes to surgeons, so start there. The No. 1 reason for unexpected hospital admission in the outpatient setting is pain; the second is PONV. Regional anesthesia addresses both. Our experience administering 30,000 blocks shows that regional anesthesia can provide excellent anesthesia as well as pain and PONV control and, consequently, high patient satisfaction.

With well-trained anesthesia personnel, regional anesthesia is a safer approach than general anesthesia, because it has minimal cardiopulmonary effects and reduces the metabolic and endocrine surgical stress response. It eliminates inhalational anesthesia-related PONV and can obviate inpatient stays.

You can also point out practical benefits. When the anesthesiologist administers regional anesthesia in a dedicated pre-op block area, there's no need to intubate and extubate patients intraoperatively and awaken them post-operatively. Regional anesthesia even reduces the number of post-op phone calls to surgeons, which are often pain control-related.

Dedicated pre-op block area
It's true that blocks take time to administer. A single-injection peripheral nerve block, for example, takes from five to 10 minutes. The solution? Create a pre-op block area if at all possible.

Unlike traditional hospital induction rooms, the block area is separate from the OR. This affords the anesthesiologist time to set up blocks, evaluate their effects and, if needed, re-administer anesthesia. The area must be equipped with monitoring equipment, a nerve stimulator, insulated needles, local and general anesthetics, intubation supplies, continuous infusion pumps, and a block cart containing airway emergency equipment and drugs to treat acute CNS and cardiac toxicity.

This room also affords patients privacy and offers an educational opportunity. We invite families into our block area to review treatments and teach post-op-care concepts.

Recognizing Regional Anesthesia Risks

No anesthesia technique is risk-free, including peripheral nerve blocks. Local anesthetics that inadvertently enter a vein, which in our experience occurs one or two times out of 2,000 blocks, may cause pre-seizure CNS, excitation tonic-clonic seizures or even cardiac arrest. Missed interscalene blocks may rarely result in accidental total spinal or epidural blocks (less than 1 in 10,000) if they are at the level of the neck and, if the anesthetic makes enters the cerebral spinal fluid, the patient can go into cardiac arrest. In addition, there is potential for local anesthetic toxicity, local infection and long-term neurologic complications. However, the majority of peripheral nerve injuries are related to surgery, and all of these complications are very rare. Regional anesthesia has a small inherent failure rate, too, and if the first attempt fails to fully anesthetize the target area, the anesthesiologist may perform a rescue block. With training and experience, the failure rate diminishes. About 92 percent of our regional blocks are effective on the first try; the remainder require re-blocking or adjunctive local anesthesia or, if they fail altogether, general anesthesia.

- Karen Nielsen, MD

RN Training
In the block area, nurses assist with sedation, patient positioning and peripheral nerve block placement. Our RNs operate the nerve stimulator and intermittently aspirate the syringe to ensure extravascular injection, allowing the anesthesia provider to hold the needle steady during injection. We also train them to help manage acute CNS and cardiovascular complications.

Intraoperatively, OR nurses assist with patient positioning and insensate limb protection.

In the PACU, nurses spend 10 to 15 miutes furthering the concepts taught in the block area, like multi-modal analgesia (NSAIDs, cryotherapy, acetaminophen), crutch-walking and insensate limb protection. For patients going home with pain pumps, nurses review signs and symptoms of local anesthetic toxicity and teach them how to turn local anesthetic infusions on and off, check catheter sites and remove catheters.

Staged implementation
Facilities that phase in advanced regional anesthesia programs do better than those trying to install complex programs at once. Initially, use the simplest single-injection peripheral nerve blocks (such as femoral and axillary nerve blocks) on low-risk patients who undergo relatively simple procedures. Once the team gets comfortable, employ techniques on sicker patients and for more complex procedures.

Eventually, you'll be ready for complex blocks like paravertebral, lumbar plexus, sciatic nerve, interscalene, and supraclavicular brachial plexus blocks. Continuous peripheral nerve blocks require advanced skills; attempt these only after mastering single-injection blocks.

Wave of the future
We're able to do regional anesthesia on 59 percent of our patients. Sometimes, patients lack the motivation, home support or comprehension to be good candidates, especially for continuous blocks. Other times, blocks fail to fully anesthetize the surgical area. Still, I believe regional anesthesia is the wave of the future. It provides the entire surgical team the keen sense of professional satisfaction that comes from serving patients compassionately and effectively.

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