Category Archives: Pain Medicine

Anesthesiology, Healthcare, Leadership, Medical Education, Pain Medicine, Regional Anesthesiology

Starting an Acute Pain Medicine Program: Strategies for Success

Initiating an acute pain medicine program can add significant value to a hospital and anesthesiology practice through improved postoperative pain control, faster recovery, decreased side effects, and higher patient satisfaction. In a special issue of Anesthesiology News, I published an article which presents a few suggested strategies. You can view and download this article here.

In an accompanying video interview, I was asked about the evolution of ultrasound in regional anesthesia practice as well as the growing role of ultrasound in perioperative medicine.

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Anesthesiology, Medical Education, Outcomes Research, Pain Medicine, Regional Anesthesiology, Research

The “Top 10” Regional Anesthesia Articles of 2016

I was recently asked to provide a list of my “Top 10” regional anesthesia research articles from 2016 and not to include my own. So for what it’s worth (not much!), I’m sharing them below in no particular order.

In my humble opinion, these articles from 2016 have already influenced my clinical practice, taught me to look at something differently, or made me think of a new research question.

Trends in the Use of Regional Anesthesia: Neuraxial and Peripheral Nerve Blocks. Reg Anesth Pain Med. 2016 Jan-Feb;41(1):43-9. doi: 10.1097/AAP.0000000000000342.

The Second American Society of Regional Anesthesia and Pain Medicine Evidence-Based Medicine Assessment of Ultrasound-Guided Regional Anesthesia: Executive Summary. Reg Anesth Pain Med. 2016 Mar-Apr;41(2):181-94. doi: 10.1097/AAP.0000000000000331.

Teaching ultrasound-guided regional anesthesia remotely: a feasibility study. Acta Anaesthesiol Scand. 2016 Aug;60(7):995-1002. doi: 10.1111/aas.12695.

Paravertebral block versus thoracic epidural for patients undergoing thoracotomy. Cochrane Database Syst Rev. 2016 Feb 21;2:CD009121. doi: 10.1002/14651858.CD009121.pub2.

Perineural versus intravenous dexamethasone as adjuncts to local anaesthetic brachial plexus block for shoulder surgery. Anaesthesia. 2016 Apr;71(4):380-8. doi: 10.1111/anae.13409.

Continuous Popliteal Sciatic Blocks: Does Varying Perineural Catheter Location Relative to the Sciatic Bifurcation Influence Block Effects? A Dual-Center, Randomized, Subject-Masked, Controlled Clinical Trial. Anesth Analg. 2016 May;122(5):1689-95. doi: 10.1213/ANE.0000000000001211.

A randomised controlled trial comparing meat-based with human cadaveric models for teaching ultrasound-guided regional anaesthesia. Anaesthesia. 2016 Aug;71(8):921-9. doi: 10.1111/anae.13446.

Adductor Canal Block Provides Noninferior Analgesia and Superior Quadriceps Strength Compared with Femoral Nerve Block in Anterior Cruciate Ligament Reconstruction. Anesthesiology. 2016 May;124(5):1053-64. doi: 10.1097/ALN.0000000000001045.

A radiologic and anatomic assessment of injectate spread following transmuscular quadratus lumborum block in cadavers. Anaesthesia. 2017 Jan;72(1):73-79. doi: 10.1111/anae.13647.

Regional Nerve Blocks Improve Pain and Functional Outcomes in Hip Fracture: A Randomized Controlled Trial. J Am Geriatr Soc. 2016 Dec;64(12):2433-2439. doi: 10.1111/jgs.14386.

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Anesthesiology, Healthcare, Knee Replacement, Medical Education, Pain Medicine, Regional Anesthesiology

Reality and the Ivory Tower

At our conferences and workshops focused on regional anesthesiology and acute pain medicine, we present and discuss the latest and greatest advances in nerve block techniques for patients having surgery.  As physicians and scientists, we are very familiar with the evidence supporting the use of nerve blocks for postoperative pain management.  We know they are extremely effective in preventing and treating pain, decreasing the need for opioid medications, and even avoiding the common side effects of general anesthesia such as nausea and vomiting and confusion.

ASRA 2015

We believe in them.  

We are passionate about them.  

We want all patients to have access to them.

Within the meeting sessions and sometimes in the common spaces outside the lecture halls, regional anesthesiologists often vigorously debate various things like:  the best sites and techniques for nerve block injections, needle and catheter equipment, ultrasound transducers and machines, and local anesthetic selection and use of adjuvants among other things.  

For knee replacement patients in particular, we want to provide the best form of pain management while maximizing their postoperative function.  Since 2011, dozens of research articles have studied the more distal adductor canal block for pain management in patients who undergo knee replacement as a replacement for the long-standing incumbent, the femoral nerve block.  In reality, these sites of nerve block placement are mere centimeters apart and represent different sites of injection along the same set of nerves.  Anesthesiologists and surgeons continue to debate this issue in person, in social media, and in publications.

It’s time for a reality check.

I had the opportunity to do a big data study with my friend and colleague, Dr. Stavros Memtsoudis.  In this study of over 191,000 knee replacement patients who had surgery across over 400 hospitals in the United States, only 12.1% of all patients had a peripheral nerve block of any kind!  Over 76% of patients had general anesthesia alone with no other regional analgesic technique. 

A more recent study published this month in the Journal of Arthroplasty evaluated over 219,000 patients who underwent knee replacement, and only 27.3% of patients received a peripheral nerve block.  The database used for this study was NACOR, operated by the Anesthesia Quality Institute and the American Society of Anesthesiologists.  This was brought to my attention through a Tweet sent by My Knee Guide (@mykneeguide).

Screenshot_20160817-203011

Where is the disconnect?  The efficacy of peripheral nerve blocks for pain control in patients having knee arthroplasty was first published more than 25 years ago.  It is easy to assume that such well-established evidence is being applied daily in clinical practice for the hundreds of thousands of patients who receive this surgery every year, but it’s not.  Today, there is more awareness than ever about the risks of opioids, and nerve blocks offer proven opioid-sparing pain relief.  Perhaps this is just another example of the gap separating the “ivory tower” of academics and real life.

It is easy to assume evidence is being applied daily in clinical practice, but it’s not.

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In a previous post, I wrote about the obstacles to changing clinical practice, and there are many:

  1. Lack of awareness (don’t know guidelines exist)
  2. Lack of familiarity (know guidelines exist but don’t know the details)
  3. Lack of agreement (don’t agree with recommendations)
  4. Lack of self-efficacy (don’t think they can do it)
  5. Lack of outcome expectancy (don’t think it will work)
  6. Inertia (don’t want to change)
  7. External barriers (want to change but blocked by system factors)

Maybe it’s time to focus less on debating minor differences in the ways we do blocks and focus more on figuring out how to make sure more patients actually get them.  

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Anesthesiology, Medical Education, Pain Medicine, Regional Anesthesiology

The Future of Acute Pain Medicine Training

AVC.Pain_We all know that not all pain is the same. While chronic pain can sometimes be palliated, “acute” pain (new onset, often with an identifiable cause) must be aggressively managed and, ideally, eliminated. This requires a systems-based approach led by physicians dedicated to understanding acute pain pathophysiology and investigating new ways to treat it. 

The #opioidepidemic has given us more reason to elevate acute #pain training and science.

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In December 2013, I submitted a 161-page letter to the Accreditation Council for Graduate Medical Education (ACGME) requesting that regional anesthesiology and acute pain medicine be considered for fellowship accreditation, with a lot of help from a small group of fellowship directors and colleagues from obstetric anesthesiology who recently went through the ACGME accreditation process for their fellowships. With no requests for further information, the Board of Directors of the ACGME informed me in the fall of 2014 that Regional Anesthesiology and Acute Pain Medicine (RAAPM) will be the next accredited subspecialty fellowship within the core discipline of Anesthesiology.  The draft program requirements have been posted online for public comments.  After the comment period, these program requirements will be revised and then finalized for posting by the ACGME. At that point, which may be as early as the end of this year, institutions with RAAPM fellowships will be invited to apply for accreditation.

I have received many questions from ASRA members about this process to date, so below I have provided some of my answers to the most common ones:

Why do we need “another” fellowship dedicated to pain medicine?  Although we already have a board-certified subspecialty of Pain Medicine within Anesthesiology, there is a growing demand for physicians who specialize in hospital-based acute pain medicine. For Pain Medicine fellows, the required “Acute Pain Inpatient Experience” may be satisfied by documented involvement with a minimum of only 50 new patients and the spectrum of pain diagnoses and treatments that they are required to learn during one year is vast. Further, Pain Medicine is a board-certified subspecialty of Emergency Medicine, Family Medicine, Physical Medicine and Rehabilitation, and Psychiatry and Neurology, in addition to Anesthesiology; graduates from any of these residency programs can be accepted into the one-year Pain Medicine fellowship and will not be as familiar with surgical or trauma-induced acute pain as an anesthesiology residency graduate. Anesthesiology is a hospital-based medical specialty, and anesthesiologists are physicians who focus on a  daily basis on the prevention and treatment of pain for their patients who undergo surgery, suffer trauma, or present for childbirth. History also supports the evolution of acute pain medicine through anesthesiology. The concept of an anesthesiology-led acute pain management service was described first in 1988 (1), but arguably the techniques employed in modern acute pain medicine and regional anesthesiology date back to Gaston Labat’s publication of Regional Anesthesia: Its Technic and Clinical Application in 1922, with advancement and refinement of this subspecialty in the 1960s and 1970s (2-6). Finally, a recent survey study shows that the great majority (83.7%) of practicing pain physicians in the United States focus only on chronic pain (7).

Over 80% of practicing #pain physicians in the US focus only on chronic pain and not acute.

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Why do anesthesiology residency graduates still need to do a fellowship in RAAPM? By the time they complete the core residency in anesthesiology today, not all residents have gained sufficient clinical experience to provide optimal care for the complete spectrum of issues experienced by patients suffering from acutely painful conditions, including the ability to reliably provide advanced interventional techniques proven to be effective in managing pain in the acute setting (8-12). We need physician leaders who can run acute pain medicine teams and design systems to provide individualized, comprehensive, and timely pain management for both medical and surgical patients in the hospital, expeditiously managing requests for assistance when pain intensity levels exceed those set forth in quality standards, or to prevent pain intensity from reaching such levels. The mission statement for the Acute Pain Medicine Special Interest Group within the American Academy of Pain Medicine provides clear justification.

Will RAAPM fellowship graduates get jobs when they are done? Although no one can make this guarantee, there are good reasons to think that there will be growing demand for RAAPM graduates in the future. In a survey of fellowship graduates and academic chairs published in 2005, 61 of 132 of academic chairs responded (46%), noting that future staffing models for their department will likely include an average of two additional faculty trained in regional anesthesiology and acute pain medicine (13). RAAPM fellowship graduates are the only physicians who can say that their subspecialty training is entirely dedicated to improving the patient experience. The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey is administered to a random sample of patients who have received inpatient care and receive government insurance through Center for Medicare and Medicaid Services (CMS). The survey consists of 32 questions and is intended to assess the “patient experience of care” domain in the value-based purchasing program. A hospital’s survey scores are publicly disclosed and make up 30% of the formula used to determine how much of its diagnosis-related group payment withholding will be paid by CMS at the end of each year. Of the 32 questions, 7 directly or indirectly relate to in-hospital pain management.

Are we ready for accreditation? Currently, there are over 60 institutions in the United States and Canada that list themselves as having nonaccredited fellowship training programs focused on RAAPM on the ASRA website. Since 2002, the group of regional anesthesiology and acute pain medicine fellowship directors has been meeting twice yearly at the ASRA Annual Spring Meeting and the American Society of Anesthesiologists (ASA) Annual Meeting in the fall. Despite not being an ACGME-accredited fellowship, this group, has been voluntarily engaged in developing and refining training guidelines as the foundation for the fellowship. These guidelines, originally published in Regional Anesthesia and Pain Medicine in 2005 (14) with a revision in 2011 (15) have been recently released as the third edition (16). Formal ACGME program requirements will serve as a measuring stick to hopefully ensure that the certificates that RAAPM fellowship graduates receive from all accredited programs will share some common value.

As with other medical subspecialties, acute pain medicine has emerged due to the need for trained specialists—in this case, those who possess the knowledge, skills, and abilities to efficiently manage a high volume of inpatient consultations, anticipate the analgesic needs of a wide range of patients based on preoperative risk, use a multimodal approach to manage and prevent pain when possible, and aggressively treat severe acute pain when it occurs to prevent it from transitioning into chronic pain. The RAAPM fellowship graduate must be a physician leader who is capable of collaborating with other healthcare providers in anesthesiology, surgery, medicine, nursing, pharmacy, physical therapy, and more to establish multidisciplinary programs that add value and improve patient care in the hospital setting and beyond.

This article originally appeared in the February 2016 issue of ASRA News.  As of October 2016, the regional anesthesiology and acute pain medicine is the newest accredited subspecialty fellowship within anesthesiology, and programs may now apply for accreditation to the ACGME.

REFERENCES

  1. Ready LB, Oden R, Chadwick HS, Benedetti C, Rooke GA, Caplan R, Wild LM. Development of an anesthesiology-based postoperative pain management service. Anesthesiology. 1988; 68:100-6.
  2. Winnie AP, Ramamurthy S, Durrani Z. The inguinal paravascular technic of lumbar plexus anesthesia: the “3-in-1 block.” Anesth Analg. 1973; 52:989-96.
  3. Winnie AP, Collins VJ. The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology. 1964; 25:353-63.
  4. Raj PP, Montgomery SJ, Nettles D, Jenkins MT Infraclavicular brachial plexus block–a new approach. Anesth Analg. 1973; 52:897-904.
  5. Raj PP, Parks RI, Watson TD, Jenkins MT. A new single-position supine approach to sciatic-femoral nerve block. Anesth Analg. 1975; 54:489-93.
  6. Raj PP, Rosenblatt R, Miller J, Katz RL, Carden E. Dynamics of local-anesthetic compounds in regional anesthesia. Anesth Analg 1977; 56: 110-7.
  7. Breuer B, Pappagallo M, Tai JY, Portenoy RK. U.S. board-certified pain physician practices: uniformity and census data of their locations. J Pain. 2007; 8: 244-50.
  8. Buvanendran A, Kroin JS. Multimodal analgesia for controlling acute postoperative pain. Curr Opin Anaesthesiol. 2009; 22: 588-93.
  9. Hebl JR, Dilger JA, Byer DE, Kopp SL, Stevens SR, Pagnano MW, Hanssen AD, Horlocker TT. A pre-emptive multimodal pathway featuring peripheral nerve block improves perioperative outcomes after major orthopedic surgery. Reg Anesth Pain Med. 2008; 33: 510-7.
  10. Jin F, Chung F. Multimodal analgesia for postoperative pain control. J Clin Anesth. 2001; 13: 524-39.
  11. Kehlet H, Dahl JB. The value of “multimodal” or “balanced analgesia” in postoperative pain treatment. Anesth Analg. 1993; 77: 1048-56.
  12. Young A, Buvanendran A.Recent advances in multimodal analgesia. Anesthesiol Clin. 2012; 30: 91-100.
  13. Neal JM, Kopacz DJ, Liguori GA, Beckman JD, Hargett MJ. The training and careers of regional anesthesia fellows–1983-2002. Reg Anesth Pain Med. 2005; 30: 226-32.
  14. Hargett MJ, Beckman JD, Liguori GA, Neal JM. Guidelines for regional anesthesia fellowship training. Reg Anesth Pain Med. 2005; 30: 218-25.
  15. Regional Anesthesiology and Acute Pain Medicine Fellowship Directors Group. Guidelines for fellowship training in regional anesthesiology and acute pain medicine: second edition, 2010. Reg Anesth Pain Med. 2011; 36: 282-8.
  16. Regional Anesthesiology and Acute Pain Medicine Fellowship Directors Group. Guidelines for fellowship training in regional anesthesiology and acute pain medicine: third edition, 2014. Reg Anesth Pain Med. 2015; 40: 213-7.

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Anesthesiology, Healthcare, Outcomes Research, Pain Medicine, Patient Safety, Regional Anesthesiology

Pain Medicine, Perioperative Surgical Home, and the Patient Experience

VAPAHealthcare around the world is changing. In the United States, healthcare reform has been focused on achieving the “triple aim” as described by Berwick (1). This triple aim encompasses 3 goals: improving the patient experience, reducing costs of care, and improving population health. The Perioperative Surgical Home (PSH) is a conceptual model introduced by the American Society of Anesthesiologists (ASA) in the past 5 years that may serve as an integrator to help hospitals achieve the triple aim (2). PSH is defined as “a patient-centered, physician anesthesiologist-led, multidisciplinary team-based practice model that coordinates surgical patient care throughout the continuum from the decision to pursue surgery through convalescence” (3). In reality, a PSH can take many forms, and the concept is analogous to the “Perioperative Medicine: the Pathway to Better Surgical Care” initiative by the Royal College of Anaesthetists in the United Kingdom. To date, there have been few published descriptions of actual PSH programs.

#Pain medicine is woven throughout perioperative care and #PtExp

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Role of Pain Medicine in the PSH

Pain medicine is woven throughout the three main elements of the PSH: preoperative preparation, intraoperative care, and postoperative recovery and rehabilitation (4). Preoperatively, anesthesiologists and pain medicine specialists have an opportunity to influence patient care by identifying patients who are considered high risk for surgery and tailor an individualized preoperative preparation plan for them. For example, the patient with chronic pain treated with long-acting opioids may benefit from optimizing the preoperative analgesic medication regimen, even tapering the opioid dose, or prescribing cognitive, behavioral, or physical therapy prior to elective major surgery like lower extremity joint replacement. During the intraoperative period, anesthetic protocols provide consistent care for surgical patients, and implementing clinical pathways that include regional anesthesia techniques have been shown to decrease perioperative opioid use and improve outcomes. For patients who have surgery, pain has a profound influence on the hospital experience. In the United States, the patient experience of care is one of three domains that influence hospital incentive payment amounts from the Center for Medicare and Medicaid Services. Patient experience is assessed using a survey, and 7 of 32 questions directly or indirectly relate to pain management (5). After the immediate postoperative period, integrated pain management can help patients achieve physical therapy goals and facilitate the transition to after-hospital rehabilitation. For challenging patients with chronic pain, this process may require careful coordination between the in-hospital anesthesiologist, outpatient pain clinic physician, and primary care physician (4).

Perioperative care of chronic #pain patients takes multi-disciplinary coordination

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Thinking Beyond Pain

The practice of anesthesiology in the United States is evolving, and there is a greater emphasis on demonstrating value. Anesthesiologists have historically been successful in establishing perioperative clinical pathways that improve acute pain management especially in orthopedic surgery, and setting up regional anesthesia and acute pain medicine programs has played a key role (6). However, competing priorities require revision of clinical pathways from time to time. For example, concerns regarding quadriceps muscle weakness with femoral nerve blocks (7) and the potential for falls (8) have led to innovations in selective nerve block techniques for knee replacement patients (9) and greater achievements in functional rehabilitation (10). By establishing a PSH model, anesthesiologists have greater opportunity but also greater responsibility for reducing perioperative complications that may or may not typically be considered within the realm of anesthesiology (11).

Future Directions

physical_med_rehab_indexTo date, anesthetic interventions focused on targeting acute pain have not demonstrated long-term functional benefits (12,13). Perhaps implementation of a PSH with better care coordination that includes individualized preoperative preparation and follow-up after surgery during rehabilitation will have greater potential for positive long-term outcomes. In addition to improvements in functional outcomes, a PSH may be able to provide patients a smoother transition from hospital to home in terms of pain management and decrease the incidence of chronic pain after common elective procedures like joint replacement (14). Finally, more health economic research is needed to prove the financial benefits of a PSH in terms of cost savings for hospitals.

Need to focus #research on long-term outcomes after #anesthesia and #surgery

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In summary, the PSH is a model that can be applied many ways to provide coordinated care of the surgical patient from the decision to proceed with surgery through convalescence. Pain medicine plays an integral role in any PSH implementation. However, to be effective, anesthesiologists as leaders of the PSH need to target improvement strategies beyond pain outcomes and the immediate postoperative period.

References

  1. Berwick DM, Nolan TW, Whittington J: The triple aim: care, health, and cost. Health Aff (Millwood) 2008; 27: 759-69
  2. Vetter TR, Boudreaux AM, Jones KA, Hunter JM, Jr., Pittet JF: The perioperative surgical home: how anesthesiology can collaboratively achieve and leverage the triple aim in health care. Anesth Analg 2014; 118: 1131-6
  3. Mariano ER, Walters TL, Kim TE, Kain ZN: Why the perioperative surgical home makes sense for veterans affairs health care. Anesth Analg 2015; 120: 1163-6
  4. Walters TL, Mariano ER, Clark JD: Perioperative Surgical Home and the Integral Role of Pain Medicine. Pain Med 2015; 16: 1666-72
  5. Mariano ER, Miller B, Salinas FV: The expanding role of multimodal analgesia in acute perioperative pain management. Adv Anesth 2013; 31: 119-136
  6. Mariano ER: Making it work: setting up a regional anesthesia program that provides value. Anesthesiol Clin 2008; 26: 681-92, vi
  7. Charous MT, Madison SJ, Suresh PJ, Sandhu NS, Loland VJ, Mariano ER, Donohue MC, Dutton PH, Ferguson EJ, Ilfeld BM: Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block. Anesthesiology 2011; 115: 774-81
  8. Feibel RJ, Dervin GF, Kim PR, Beaule PE: Major complications associated with femoral nerve catheters for knee arthroplasty: a word of caution. J Arthroplasty 2009; 24: 132-7
  9. Lund J, Jenstrup MT, Jaeger P, Sorensen AM, Dahl JB: Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. Acta Anaesthesiol Scand 2011; 55: 14-9
  10. Mudumbai SC, Kim TE, Howard SK, Workman JJ, Giori N, Woolson S, Ganaway T, King R, Mariano ER: Continuous adductor canal blocks are superior to continuous femoral nerve blocks in promoting early ambulation after TKA. Clin Orthop Relat Res 2014; 472: 1377-83
  11. Kim TE, Mariano ER: Developing a Multidisciplinary Fall Reduction Program for Lower-Extremity Joint Arthroplasty Patients. Anesthesiol Clin 2014; 32: 853-864
  12. Ilfeld BM, Ball ST, Gearen PF, Mariano ER, Le LT, Vandenborne K, Duncan PW, Sessler DI, Enneking FK, Shuster JJ, Maldonado RC, Meyer RS: Health-related quality of life after hip arthroplasty with and without an extended-duration continuous posterior lumbar plexus nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009; 109: 586-91
  13. Ilfeld BM, Shuster JJ, Theriaque DW, Mariano ER, Girard PJ, Loland VJ, Meyer S, Donovan JF, Pugh GA, Le LT, Sessler DI, Ball ST: Long-term pain, stiffness, and functional disability after total knee arthroplasty with and without an extended ambulatory continuous femoral nerve block: a prospective, 1-year follow-up of a multicenter, randomized, triple-masked, placebo-controlled trial. Reg Anesth Pain Med 2011; 36: 116-20
  14. Lavand’homme PM, Grosu I, France MN, Thienpont E: Pain trajectories identify patients at risk of persistent pain after knee arthroplasty: an observational study. Clin Orthop Relat Res 2014; 472: 1409-15

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Knee Replacement, Medical Education, Pain Medicine, Regional Anesthesiology

Multimodal Pain Relief after Knee Replacement

Knee-pain 2Knee replacement is one of the most commonly performed operations in the United States with over 700,000 procedures performed annually (1). Besides providing anesthesia care in the operating room, anesthesiologists are dedicated to providing the best perioperative pain management in order to improve patients’ function and facilitate rehabilitation after surgery. In the past, pain management was limited to the use of opioids (narcotics). Opioids only attack pain in one way, and just adding more opioids does not usually lead to better pain control.

Today, we have more options at our disposal to help fight #pain after #kneereplacement.

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In 2012, the American Society of Anesthesiologists (ASA) published its guidelines for acute pain management in the perioperative setting (2). This document recommends “multimodal analgesia” which means that two or more classes of pain medications or therapies, working with different mechanisms of action, should be used in the treatment of acute pain.

While opioids are still important pain medications, they should be combined with other classes of medications known to help relieve postoperative pain unless contraindicated. These include:

  • Non-steroidal anti-inflammatory drugs (NSAIDs): Examples include ibuprofen, diclofenac, ketorolac, celecoxib. NSAIDs act on the prostaglandin system peripherally and work to decrease inflammation.
  • Acetaminophen: Acetaminophen acts on central prostaglandin synthesis and provides pain relief through multiple mechanisms.
  • Gabapentinoids: Examples include gabapentin and pregabalin. These medications are membrane stabilizers that essentially decrease nerve firing.

The ASA also strongly recommends the use of regional analgesic techniques as part of the multimodal analgesic protocol when indicated.

Epidural Analgesia

When compared to opioids alone, epidural analgesia produces lower pain scores and shorter time to achieve physical therapy goals (3). However, higher dose of local anesthetic (numbing medicine) may lead to muscle weakness that can limit activity (4). In addition, epidural analgesia can lead to common side effects (urinary retention, dizziness, itchiness) and is not selective for the operative leg, meaning that the non-operative leg may also become numb.

Femoral Nerve Block

A peripheral nerve block of the femoral nerve is specific to the operative leg. When compared to opioids alone, a femoral nerve block provides better pain control and leads to higher patient satisfaction (5). One area of controversy is whether a single-injection nerve block or catheter-based technique is preferred. There is evidence to support the use of continuous nerve block catheters to extend the pain relief and opioid-sparing benefits of nerve blocks in patients having major surgery like knee replacement. When a continuous femoral nerve block catheter is used, the pain relief is comparable to an epidural but without the epidural-related side effects (6). One legitimate concern raised over the use of femoral nerve blocks in knee replacement patients is the resulting quadriceps muscle weakness (7).

From Gray's Anatomy
From Gray’s Anatomy

Saphenous Nerve Block (Adductor Canal Block)

The saphenous nerve is the largest sensory branch of the femoral nerve and can be blocked within the adductor canal to provide postoperative pain relief and facilitate rehabilitation (8, 9). In healthy volunteers, quadriceps strength is better preserved when subjects receive an adductor canal block compared to a femoral nerve block (10).

In actual knee replacement patients, quadriceps function decreases regardless of nerve block type after surgery but to a lesser degree with adductor canal blocks (11). Recently there have been reports of quadriceps weakness resulting from adductor canal blocks and catheters that have affected clinical care (12, 13).

Fall Risk

According to a large retrospective study of almost 200,000 cases, the incidence of inpatient falls for patients after TKA is 1.6%, and perioperative use of nerve blocks is not associated with increased risk (14). Patient factors that increase the risk of falls include higher age, male sex, sleep apnea, delirium, anemia requiring blood transfusion, and intraoperative use of general anesthesia (14). The bottom line is that all knee replacement patients are at increased risk for falling due to multiple risk factors, and any clinical pathway should include fall prevention strategies and an emphasis on patient safety.

Other Local Anesthetic Techniques

In addition to a femoral nerve or adductor canal block, a sciatic nerve block is sometimes offered to provide a “complete” block of the leg. There are studies for and against this practice. Arguably, the benefit of a sciatic nerve block does not last beyond the first postoperative day (15). Surgeon-administered local anesthetic around the knee joint (local infiltration analgesia) can be combined with nerve block techniques to provide additional postoperative pain relief for the first few hours after surgery (16, 17).

For more information about anesthetic options for knee replacement, please see my post on My Knee Guide.

References

  1. The Center for Disease Control and Prevention. FastStats: Inpatient Surgery. National Hospital Discharge Survey: 2010 table. http://www.cdc.gov/nchs/fastats/inpatient-surgery.htm. Accessed January 30, 2015.
  2. American Society of Anesthesiologists Task Force on Acute Pain M: Practice guidelines for acute pain management in the perioperative setting: an updated report by the American Society of Anesthesiologists Task Force on Acute Pain Management. Anesthesiology 2012, 116(2):248-273.
  3. Mahoney OM, Noble PC, Davidson J, Tullos HS: The effect of continuous epidural analgesia on postoperative pain, rehabilitation, and duration of hospitalization in total knee arthroplasty. Clin Orthop Relat Res 1990(260):30-37.
  4. Raj PP, Knarr DC, Vigdorth E, Denson DD, Pither CE, Hartrick CT, Hopson CN, Edstrom HH: Comparison of continuous epidural infusion of a local anesthetic and administration of systemic narcotics in the management of pain after total knee replacement surgery. Anesth Analg 1987, 66(5):401-406.
  5. Chan EY, Fransen M, Parker DA, Assam PN, Chua N: Femoral nerve blocks for acute postoperative pain after knee replacement surgery. Cochrane Database Syst Rev 2014, 5:CD009941.
  6. Barrington MJ, Olive D, Low K, Scott DA, Brittain J, Choong P: Continuous femoral nerve blockade or epidural analgesia after total knee replacement: a prospective randomized controlled trial. Anesth Analg 2005, 101(6):1824-1829.
  7. Charous MT, Madison SJ, Suresh PJ, Sandhu NS, Loland VJ, Mariano ER, Donohue MC, Dutton PH, Ferguson EJ, Ilfeld BM: Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block. Anesthesiology 2011, 115(4):774-781.
  8. Jenstrup MT, Jaeger P, Lund J, Fomsgaard JS, Bache S, Mathiesen O, Larsen TK, Dahl JB: Effects of adductor-canal-blockade on pain and ambulation after total knee arthroplasty: a randomized study. Acta Anaesthesiol Scand 2012, 56(3):357-364.
  9. Hanson NA, Allen CJ, Hostetter LS, Nagy R, Derby RE, Slee AE, Arslan A, Auyong DB: Continuous ultrasound-guided adductor canal block for total knee arthroplasty: a randomized, double-blind trial. Anesth Analg 2014, 118(6):1370-1377.
  10. Kwofie MK, Shastri UD, Gadsden JC, Sinha SK, Abrams JH, Xu D, Salviz EA: The effects of ultrasound-guided adductor canal block versus femoral nerve block on quadriceps strength and fall risk: a blinded, randomized trial of volunteers. Reg Anesth Pain Med 2013, 38(4):321-325.
  11. Jaeger P, Zaric D, Fomsgaard JS, Hilsted KL, Bjerregaard J, Gyrn J, Mathiesen O, Larsen TK, Dahl JB: Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study. Reg Anesth Pain Med 2013, 38(6):526-532.
  12. Chen J, Lesser JB, Hadzic A, Reiss W, Resta-Flarer F: Adductor canal block can result in motor block of the quadriceps muscle. Reg Anesth Pain Med 2014, 39(2):170-171.
  13. Veal C, Auyong DB, Hanson NA, Allen CJ, Strodtbeck W: Delayed quadriceps weakness after continuous adductor canal block for total knee arthroplasty: a case report. Acta Anaesthesiol Scand 2014, 58(3):362-364.
  14. Memtsoudis SG, Danninger T, Rasul R, Poeran J, Gerner P, Stundner O, Mariano ER, Mazumdar M: Inpatient falls after total knee arthroplasty: the role of anesthesia type and peripheral nerve blocks. Anesthesiology 2014, 120(3):551-563.
  15. Abdallah FW, Brull R: Is sciatic nerve block advantageous when combined with femoral nerve block for postoperative analgesia following total knee arthroplasty? A systematic review. Reg Anesth Pain Med 2011, 36(5):493-498.
  16. Mudumbai SC, Kim TE, Howard SK, Workman JJ, Giori N, Woolson S, Ganaway T, King R, Mariano ER: Continuous adductor canal blocks are superior to continuous femoral nerve blocks in promoting early ambulation after TKA. Clin Orthop Relat Res 2014, 472(5):1377-1383.
  17. Mariano ER, Kim TE, Wagner MJ, Funck N, Harrison TK, Walters T, Giori N, Woolson S, Ganaway T, Howard SK: A randomized comparison of proximal and distal ultrasound-guided adductor canal catheter insertion sites for knee arthroplasty. J Ultrasound Med 2014, 33(9):1653-1662.

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Anesthesiology, Medical Education, Pain Medicine, Regional Anesthesiology

Extending Nerve Block Pain Relief after Surgery: Review of the Evidence

nerve firingNerve blocks (also referred to as “regional anesthesia”) offer patients many potential advantages in the immediate postoperative period such as decreased pain, nausea and vomiting, and time spent in the recovery room (1,2). However, these beneficial effects are time-limited and do not last beyond the duration of the block (2). While the clinical effects of nerve blocks typically last long enough for patients to meet discharge eligibility from recovery and avoid hospitalization for pain control (3), these results can be easily negated if patients’ pain or opioid-related side effects warrant a return trip to the hospital and readmission following block resolution (4). Thus, extending block duration to provide longer-term, site-specific analgesia for patients on an ambulatory basis has been a high research priority. What options are currently available?

Continuous Peripheral Nerve Blocks

Continuous peripheral nerve block (CPNB) techniques (also known as perineural catheters) permit delivery of local anesthetic solutions to the site of a peripheral nerve on an ongoing basis (5). Portable infusion devices can deliver a solution of plain local anesthetic for days after surgery, often with the ability to titrate the dose up and down or even stop the infusion temporarily when patients feel too numb (6,7). In a meta-analysis comparing CPNB to single-injection peripheral nerve blocks, CPNB results in lower patient-reported worst pain scores and pain scores at rest on postoperative day (POD) 0, 1, and 2 (8). Patients who receive CPNB also experience less nausea, consume less opioids, sleep better, and are more satisfied with pain management (8). We also know how CPNB works: local anesthetic medication interrupts nerve transmission, so patients experience decreased sensation.

Managing CPNB patients (especially at home) can sometimes be challenging, and not all patients are good candidates for outpatient perineural infusion (7). Patients must have a reliable means of follow-up and should have a caretaker at home for at least the first night after surgery (7). A health care provider must be available at all times to manage common issues associated with CPNB and call patients once daily to assess for analgesic efficacy and side effects (9). Patients, especially those undergoing lower extremity surgery, and their caretakers should receive clear instructions regarding the care of their infusion device and catheter as well as their anesthetized extremities (10,11) including fall precautions (12,13).

Although the optimal duration for CPNB is unknown, 2 to 7 days has been reported for orthopedic inpatients (14) with durations as long as 34 days under special circumstances (15). At the completion of the local anesthetic infusion, perineural catheters must be removed. To date, CPNB is the only technique that offers patients the longest potential duration of block paired with the ability to titrate to the desired level of block.

Despite more than a decade of published data supporting CPNB for extending the duration of postoperative pain control, adoption of these techniques is not universal. Many of the issues are arguably system-based, and the lack of a “block” room (16) or time pressure (17) may be responsible. However, lack of training in these techniques may also be a factor (18) or negative experiences with failed placement attempts using traditional techniques (19).

Adjuvants to Local Anesthetic Solutions for Single-Injection Peripheral Nerve Blocks

For nerve blocks intended to last 1-2 days, there are a few options.  Long-acting local anesthetics (e.g., bupivacaine, levobupivacaine, and ropivacaine) generally provide analgesia of similar duration for 24 hours or less (20-23). Several different drugs have been investigated for their potential to extend single-injection peripheral nerve block duration when added to local anesthetic solutions. Epinephrine when added to local anesthetic solutions provides vasoconstriction to decrease uptake but has little or no clinical effect on the duration of longer-acting local anesthetics (24). Opioids in general do not provide additional benefits in terms of duration (25) except for buprenorphine (26) although how it works is unclear. To date, there are insufficient data to support the addition of tramadol or neostigmine to local anesthetic solutions (25). Of the available adjuvants, clonidine has been demonstrated in clinical studies and systematic reviews to extend the duration of analgesia for intermediate-acting local anesthetics (e.g., mepivacaine) with few side effects in doses up to 150 mcg but probably do not extend long-acting local anesthetics (25,27). There has been increasing interest in dexamethasone as an adjuvant to local anesthetic solutions based on clinical reports of extended duration when added to intermediate-acting local anesthetics (28,29). The mechanism is not well understood and may be less pronounced with long-acting local anesthetics; one study reported block durations of only 22 hours with dexamethasone added to either ropivacaine or bupivacaine (30). Giving dexamethasone intravenously may actually produce the same effect (31). Caution is warranted when experimenting with adjuvant mixtures that have not been specifically approved for nerve blocks (i.e., “off-label” use) as many of the usual FDA safeguards have not been performed, and these drugs may contribute to neurotoxicity or other side effects not yet known.

Novel Extended-Duration Local Anesthetics

There has been interest in liposomal formulations of extended-release bupivacaine for regional anesthesia for over two decades (32,33). A recent formulation consisting of bupivacaine encapsulated in multivesicular liposomes to produce slow release is FDA-approved for local infiltration (34) but not yet for nerve blocks although this is expected soon. A nerve block with liposomal bupivacaine can be expected to last 1-3 days. Initial nerve block studies in animals suggest a lower maximum serum concentration with the liposomal formulation compared to plain bupivacaine (35)–unless co-administered with lidocaine which facilitates release of liposomal bupivacaine (36)–and epidural administration in human volunteers more than doubles duration of sensory block (37). Once it receives FDA approval, I expect many comparative studies versus CPNB for postoperative analgesia. There are still concerns regarding local anesthetic systemic toxicity with liposomal bupivacaine as well as prolonged motor block and unpleasant numbness given the drug’s long-lasting effects. In addition, there is no option for “giving more” to augment a block in the event of inadequate pain relief.

In summary, there are currently few options to extend the duration of regional analgesia at home beyond the one day expected from most single-injection nerve blocks. CPNB with plain local anesthetic perineural infusion is the most established way to provide days of postoperative pain control and allows titration, but training in insertion techniques and a system to manage ambulatory CPNB patients are necessary. Adjuvants or liposomal formulations of local anesthetics may offer potential options for limited extension of block duration, but further studies regarding efficacy and safety for regional anesthesia as well as comparative-effectiveness versus CPNB are necessary. For major surgery like total knee replacement, block duration of several days may be optimal (38).

References

  1. Liu SS, Strodtbeck WM, Richman JM, Wu CL: A comparison of regional versus general anesthesia for ambulatory anesthesia: a meta-analysis of randomized controlled trials. Anesth Analg 2005; 101: 1634-42
  2. McCartney CJ, Brull R, Chan VW, Katz J, Abbas S, Graham B, Nova H, Rawson R, Anastakis DJ, von Schroeder H: Early but no long-term benefit of regional compared with general anesthesia for ambulatory hand surgery. Anesthesiology 2004; 101: 461-7
  3. Williams BA, Kentor ML, Vogt MT, Williams JP, Chelly JE, Valalik S, Harner CD, Fu FH: Femoral-sciatic nerve blocks for complex outpatient knee surgery are associated with less postoperative pain before same-day discharge: a review of 1,200 consecutive cases from the period 1996-1999. Anesthesiology 2003; 98: 1206-13
  4. Williams BA, Kentor ML, Vogt MT, Vogt WB, Coley KC, Williams JP, Roberts MS, Chelly JE, Harner CD, Fu FH: Economics of nerve block pain management after anterior cruciate ligament reconstruction: potential hospital cost savings via associated postanesthesia care unit bypass and same-day discharge. Anesthesiology 2004; 100: 697-706
  5. Ilfeld BM: Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011; 113: 904-25
  6. Ilfeld BM: Continuous peripheral nerve blocks in the hospital and at home. Anesthesiol Clin 2011; 29: 193-211
  7. Ilfeld BM, Enneking FK: Continuous peripheral nerve blocks at home: a review. Anesth Analg 2005; 100: 1822-33
  8. Bingham AE, Fu R, Horn JL, Abrahams MS: Continuous peripheral nerve block compared with single-injection peripheral nerve block: a systematic review and meta-analysis of randomized controlled trials. Reg Anesth Pain Med 2012; 37: 583-94
  9. Ilfeld BM, Esener DE, Morey TE, Enneking FK: Ambulatory perineural infusion: the patients’ perspective. Reg Anesth Pain Med 2003; 28: 418-23
  10. Charous MT, Madison SJ, Suresh PJ, Sandhu NS, Loland VJ, Mariano ER, Donohue MC, Dutton PH, Ferguson EJ, Ilfeld BM: Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block. Anesthesiology 2011; 115: 774-81
  11. Ilfeld BM, Moeller LK, Mariano ER, Loland VJ, Stevens-Lapsley JE, Fleisher AS, Girard PJ, Donohue MC, Ferguson EJ, Ball ST: Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well? Anesthesiology 2010; 112: 347-54
  12. Feibel RJ, Dervin GF, Kim PR, Beaule PE: Major complications associated with femoral nerve catheters for knee arthroplasty: a word of caution. J Arthroplasty 2009; 24: 132-7
  13. Ilfeld BM, Duke KB, Donohue MC: The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Anesth Analg 2010; 111: 1552-4
  14. Capdevila X, Pirat P, Bringuier S, Gaertner E, Singelyn F, Bernard N, Choquet O, Bouaziz H, Bonnet F: Continuous peripheral nerve blocks in hospital wards after orthopedic surgery: a multicenter prospective analysis of the quality of postoperative analgesia and complications in 1,416 patients. Anesthesiology 2005; 103: 1035-45
  15. Stojadinovic A, Auton A, Peoples GE, McKnight GM, Shields C, Croll SM, Bleckner LL, Winkley J, Maniscalco-Theberge ME, Buckenmaier CC, 3rd: Responding to challenges in modern combat casualty care: innovative use of advanced regional anesthesia. Pain Med 2006; 7: 330-8
  16. Mariano ER, Chu LF, Peinado CR, Mazzei WJ: Anesthesia-controlled time and turnover time for ambulatory upper extremity surgery performed with regional versus general anesthesia. J Clin Anesth 2009; 21: 253-7
  17. Oldman M, McCartney CJ, Leung A, Rawson R, Perlas A, Gadsden J, Chan VW: A survey of orthopedic surgeons’ attitudes and knowledge regarding regional anesthesia. Anesth Analg 2004; 98: 1486-90, table of contents
  18. Hadzic A, Vloka JD, Kuroda MM, Koorn R, Birnbach DJ: The practice of peripheral nerve blocks in the United States: a national survey [p2e comments]. Reg Anesth Pain Med 1998; 23: 241-6
  19. Salinas FV: Location, location, location: Continuous peripheral nerve blocks and stimulating catheters. Reg Anesth Pain Med 2003; 28: 79-82
  20. Casati A, Borghi B, Fanelli G, Cerchierini E, Santorsola R, Sassoli V, Grispigni C, Torri G: A double-blinded, randomized comparison of either 0.5% levobupivacaine or 0.5% ropivacaine for sciatic nerve block. Anesth Analg 2002; 94: 987-90
  21. Hickey R, Hoffman J, Ramamurthy S: A comparison of ropivacaine 0.5% and bupivacaine 0.5% for brachial plexus block. Anesthesiology 1991; 74: 639-42
  22. Klein SM, Greengrass RA, Steele SM, D’Ercole FJ, Speer KP, Gleason DH, DeLong ER, Warner DS: A comparison of 0.5% bupivacaine, 0.5% ropivacaine, and 0.75% ropivacaine for interscalene brachial plexus block. Anesth Analg 1998; 87: 1316-9
  23. Fanelli G, Casati A, Beccaria P, Aldegheri G, Berti M, Tarantino F, Torri G: A double-blind comparison of ropivacaine, bupivacaine, and mepivacaine during sciatic and femoral nerve blockade. Anesth Analg 1998; 87: 597-600
  24. Weber A, Fournier R, Van Gessel E, Riand N, Gamulin Z: Epinephrine does not prolong the analgesia of 20 mL ropivacaine 0.5% or 0.2% in a femoral three-in-one block. Anesth Analg 2001; 93: 1327-31
  25. Murphy DB, McCartney CJ, Chan VW: Novel analgesic adjuncts for brachial plexus block: a systematic review. Anesth Analg 2000; 90: 1122-8
  26. Candido KD, Franco CD, Khan MA, Winnie AP, Raja DS: Buprenorphine added to the local anesthetic for brachial plexus block to provide postoperative analgesia in outpatients. Reg Anesth Pain Med 2001; 26: 352-6
  27. McCartney CJ, Duggan E, Apatu E: Should we add clonidine to local anesthetic for peripheral nerve blockade? A qualitative systematic review of the literature. Reg Anesth Pain Med 2007; 32: 330-8
  28. Movafegh A, Razazian M, Hajimaohamadi F, Meysamie A: Dexamethasone added to lidocaine prolongs axillary brachial plexus blockade. Anesth Analg 2006; 102: 263-7
  29. Parrington SJ, O’Donnell D, Chan VW, Brown-Shreves D, Subramanyam R, Qu M, Brull R: Dexamethasone added to mepivacaine prolongs the duration of analgesia after supraclavicular brachial plexus blockade. Reg Anesth Pain Med 2010; 35: 422-6
  30. Cummings KC, 3rd, Napierkowski DE, Parra-Sanchez I, Kurz A, Dalton JE, Brems JJ, Sessler DI: Effect of dexamethasone on the duration of interscalene nerve blocks with ropivacaine or bupivacaine. Br J Anaesth 2011; 107: 446-53
  31. Desmet M, Braems H, Reynvoet M, et al: I.V. and perineural dexamethasone are equivalent in increasing the analgesic duration of a single-shot interscalene block with ropivacaine for shoulder surgery: a prospective, randomized, placebo-controlled study. Br J Anaesth 2013; 111: 445-52
  32. Boogaerts J, Lafont N, Donnay M, Luo H, Legros FJ: Motor blockade and absence of local nerve toxicity induced by liposomal bupivacaine injected into the brachial plexus of rabbits. Acta Anaesthesiol Belg 1995; 46: 19-24
  33. Boogaerts JG, Lafont ND, Declercq AG, Luo HC, Gravet ET, Bianchi JA, Legros FJ: Epidural administration of liposome-associated bupivacaine for the management of postsurgical pain: a first study. J Clin Anesth 1994; 6: 315-20
  34. Chahar P, Cummings KC, 3rd: Liposomal bupivacaine: a review of a new bupivacaine formulation. J Pain Res 2012; 5: 257-64
  35. Richard BM, Newton P, Ott LR, Haan D, Brubaker AN, Cole PI, Ross PE, Rebelatto MC, Nelson KG: The Safety of EXPAREL (R) (Bupivacaine Liposome Injectable Suspension) Administered by Peripheral Nerve Block in Rabbits and Dogs. J Drug Deliv 2012; 2012: 962101
  36. Richard BM, Rickert DE, Doolittle D, Mize A, Liu J, Lawson CF: Pharmacokinetic Compatibility Study of Lidocaine with EXPAREL in Yucatan Miniature Pigs. ISRN Pharm 2011; 2011: 582351
  37. Viscusi ER, Candiotti KA, Onel E, Morren M, Ludbrook GL: The pharmacokinetics and pharmacodynamics of liposome bupivacaine administered via a single epidural injection to healthy volunteers. Reg Anesth Pain Med 2012; 37: 616-22
  38. Lavand’homme PM, Grosu I, France MN, Thienpont E: Pain trajectories identify patients at risk of persistent pain after knee arthroplasty: an observational study. Clin Orthop Relat Res 2014; 472: 1409-15.

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Ultrasound in Regional Anesthesia: What is the Evidence?

Medical scannerThe use of ultrasound guidance in the practice of regional anesthesia arguably began in the late 1980s (1), although ultrasound Doppler technology was used to direct needle insertion for peripheral nerve blockade in the 1970s (2). This past decade has seen a rapid increase in practical applications and clinical research in the field of ultrasound-guided regional anesthesia (UGRA), and the American Society of Regional Anesthesia and Pain Medicine (ASRA) and European Society of Regional Anesthesia have even published joint committee guidelines for training in this discipline (3).

Given the rapid adoption of UGRA, evidence to support this practice was initially limited; however, many studies have emerged in an attempt to define the role of ultrasound. In 2010, ASRA published a series of important articles which distill the body of evidence related to UGRA up to that time point (4-13). Additional studies have been completed and published since 2010 and will be included in an update that should be published in the next year.

Ultrasound Guidance for Extremity Peripheral Nerve Blocks

The 2010 ASRA systematic reviews covering this subject include 24 RCTs which compare ultrasound guidance to an alternative nerve localization technique for either upper or lower extremity peripheral nerve blockade (5). For both upper and lower extremity blocks, the majority of studies report faster block onset when ultrasound is employed (5,6,11), although 5 of 15 studies in the upper extremity and 2 of 5 studies in the lower extremity fail to find a difference in onset time (5). There is evidence to support a decrease in procedural time when ultrasound is used for upper and lower extremity blocks (6-11); however, set-up time and pre-scanning with ultrasound are not consistently measured or reported. In terms of block quality, lower extremity studies are more likely to report an advantage with ultrasound than upper extremity studies; only 4 of 16 upper extremity studies show improvement with ultrasound, and these studies use nerve stimulation or transarterial injection as the comparator (5). When a fixed time point is used for assessing block success, ultrasound use is more likely to show an advantage although the definitions of successful block vary widely (6,11). Only one study in the upper extremity shows a difference in block duration in favor of ultrasound while all other RCTs do not demonstrate a difference (5). For femoral and subgluteal sciatic nerve blocks, ultrasound use decreases the minimum effective anesthesia volume to achieve a successful block in 50% of patients (11).

Ultrasound for Continuous Peripheral Nerve Blocks

Although many large case series describing ultrasound-guided techniques for continuous peripheral nerve block (CPNB) performance have been published, there are relatively-fewer RCTs comparing ultrasound to other nerve localization techniques for CPNB. When an exclusively ultrasound-guided technique is compared to a stimulating catheter technique, procedural duration is shorter with ultrasound at four distinct insertion sites (14-17) with less procedure-related pain for lower extremity catheters (14,16) and fewer inadvertent vascular punctures for femoral and infraclavicular catheters (14,15). Most studies report similar analgesia and other acute pain outcomes from catheters placed with ultrasound when compared to other methods (18-20), with the exception of one study involving popliteal-sciatic catheters which suggests that stimulating catheters may provide an analgesic advantage although successful placement occurs less often (21).

Ultrasound for Truncal and Neuraxial Blocks

To date, RCTs comparing ultrasound guidance to traditional techniques for paravertebral blockade or transversus abdominis plane (TAP) blocks have yet to be reported. For both of these procedures, the 2010 ASRA systematic review recommends the use of ultrasound although this recommendation is based on case series data only (4). In one study comparing ultrasound-guided TAP to conventional ilioinguinal/iliohypogastric nerve blocks for inguinal hernia repair, subjects who received ultrasound-guided TAP blocks reported lower pain scores for the first 24 hours (22). Ultrasound-guidance and the landmark-based technique for ilioinguinal/iliohypogastric nerve blocks have been compared in children with the ultrasound-guided technique resulting in decreased need for systemic analgesic supplementation (23). For neuraxial blocks, there is evidence to support ultrasound scanning prior to employing conventional neuraxial block techniques rather than relying solely on surface landmarks (10), especially in patients with challenging anatomy (24).

Ultrasound for Regional Anesthesia in Special Populations

Ultrasound-guided techniques for peripheral (25) and neuraxial (26) blocks in children have been described previously. The 2010 ASRA evidence-based review on ultrasound for pediatric regional anesthesia included 6 RCTs involving peripheral nerve blocks and one randomized trial in neuraxial blockade in addition to case series of >10 patients (12). In this population, ultrasound may improve the speed of block onset and duration of analgesia, increase success rates for truncal blocks compared to blind techniques, and reduce the volume of local anesthetic required (12). In obese patients, ultrasound may play a role in identifying target peripheral and neuraxial structures as well as real-time procedural performance (27). When performing CPNB in obese patients, procedural time is not prolonged compared to non-obese patients when as long as ultrasound is used (28).

#Ultrasound has been shown to decrease serious complications related to nerve blocks.

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MedianIn summary, there is sufficient evidence to support the use of ultrasound guidance for peripheral nerve blockade based on short-term outcomes, and the results of a large prospective registry study suggest that ultrasound may decrease in the risk of local anesthetic systemic toxicity (29). Additional prospective studies are needed to further define the role of ultrasound in neuraxial blockade, long-term patient outcomes, and advantages in special populations.

References

  1. Ting PL, Sivagnanaratnam V: Ultrasonographic study of the spread of local anaesthetic during axillary brachial plexus block. Br J Anaesth 1989; 63: 326-9
  2. la Grange P, Foster PA, Pretorius LK: Application of the Doppler ultrasound bloodflow detector in supraclavicular brachial plexus block. Br J Anaesth 1978; 50: 965-7
  3. Sites BD, Chan VW, Neal JM, Weller R, Grau T, Koscielniak-Nielsen ZJ, Ivani G: The American Society of Regional Anesthesia and Pain Medicine and the European Society Of Regional Anaesthesia and Pain Therapy Joint Committee recommendations for education and training in ultrasound-guided regional anesthesia. Reg Anesth Pain Med 2009; 34: 40-6
  4. Abrahams MS, Horn JL, Noles LM, Aziz MF: Evidence-based medicine: ultrasound guidance for truncal blocks. Reg Anesth Pain Med 2010; 35: S36-42
  5. Liu SS, Ngeow J, John RS: Evidence basis for ultrasound-guided block characteristics: onset, quality, and duration. Reg Anesth Pain Med 2010; 35: S26-35
  6. McCartney CJ, Lin L, Shastri U: Evidence basis for the use of ultrasound for upper-extremity blocks. Reg Anesth Pain Med 2010; 35: S10-5
  7. Narouze SN: Ultrasound-guided interventional procedures in pain management: Evidence-based medicine. Reg Anesth Pain Med 2010; 35: S55-8
  8. Neal JM: Ultrasound-guided regional anesthesia and patient safety: An evidence-based analysis. Reg Anesth Pain Med 2010; 35: S59-67
  9. Neal JM, Brull R, Chan VW, Grant SA, Horn JL, Liu SS, McCartney CJ, Narouze SN, Perlas A, Salinas FV, Sites BD, Tsui BC: The ASRA evidence-based medicine assessment of ultrasound-guided regional anesthesia and pain medicine: Executive summary. Reg Anesth Pain Med 2010; 35: S1-9
  10. Perlas A: Evidence for the use of ultrasound in neuraxial blocks. Reg Anesth Pain Med 2010; 35: S43-6
  11. Salinas FV: Ultrasound and review of evidence for lower extremity peripheral nerve blocks. Reg Anesth Pain Med 2010; 35: S16-25
  12. Tsui BC, Pillay JJ: Evidence-based medicine: Assessment of ultrasound imaging for regional anesthesia in infants, children, and adolescents. Reg Anesth Pain Med 2010; 35: S47-54
  13. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, McQuay HJ: Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials 1996; 17: 1-12
  14. Mariano ER, Cheng GS, Choy LP, Loland VJ, Bellars RH, Sandhu NS, Bishop ML, Lee DK, Maldonado RC, Ilfeld BM: Electrical stimulation versus ultrasound guidance for popliteal-sciatic perineural catheter insertion: a randomized controlled trial. Reg Anesth Pain Med 2009; 34: 480-5
  15. Mariano ER, Loland VJ, Bellars RH, Sandhu NS, Bishop ML, Abrams RA, Meunier MJ, Maldonado RC, Ferguson EJ, Ilfeld BM: Ultrasound guidance versus electrical stimulation for infraclavicular brachial plexus perineural catheter insertion. J Ultrasound Med 2009; 28: 1211-8
  16. Mariano ER, Loland VJ, Sandhu NS, Bellars RH, Bishop ML, Afra R, Ball ST, Meyer RS, Maldonado RC, Ilfeld BM: Ultrasound guidance versus electrical stimulation for femoral perineural catheter insertion. J Ultrasound Med 2009; 28: 1453-60
  17. Mariano ER, Loland VJ, Sandhu NS, Bellars RH, Bishop ML, Meunier MJ, Afra R, Ferguson EJ, Ilfeld BM: A trainee-based randomized comparison of stimulating interscalene perineural catheters with a new technique using ultrasound guidance alone. J Ultrasound Med 2010; 29: 329-336
  18. Ilfeld BM: Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011; 113: 904-25
  19. Fredrickson MJ, Danesh-Clough TK: Ambulatory continuous femoral analgesia for major knee surgery: a randomised study of ultrasound-guided femoral catheter placement. Anaesth Intensive Care 2009; 37: 758-66
  20. Choi S, Brull R: Is ultrasound guidance advantageous for interventional pain management? A review of acute pain outcomes. Anesth Analg 2011; 113: 596-604
  21. Mariano ER, Loland VJ, Sandhu NS, Bishop ML, Lee DK, Schwartz AK, Girard PJ, Ferguson EJ, Ilfeld BM: Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia. Can J Anaesth 2010; 57: 919-926
  22. Aveline C, Le Hetet H, Le Roux A, Vautier P, Cognet F, Vinet E, Tison C, Bonnet F: Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/iliohypogastric nerve blocks for day-case open inguinal hernia repair. Br J Anaesth 2011; 106: 380-6
  23. Willschke H, Marhofer P, Bosenberg A, Johnston S, Wanzel O, Cox SG, Sitzwohl C, Kapral S: Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children. Br J Anaesth 2005; 95: 226-30
  24. Chin KJ, Perlas A, Chan V, Brown-Shreves D, Koshkin A, Vaishnav V: Ultrasound imaging facilitates spinal anesthesia in adults with difficult surface anatomic landmarks. Anesthesiology 2011; 115: 94-101
  25. Tsui B, Suresh S: Ultrasound imaging for regional anesthesia in infants, children, and adolescents: a review of current literature and its application in the practice of extremity and trunk blocks. Anesthesiology 2010; 112: 473-92
  26. Tsui BC, Suresh S: Ultrasound imaging for regional anesthesia in infants, children, and adolescents: a review of current literature and its application in the practice of neuraxial blocks. Anesthesiology 2010; 112: 719-28
  27. Brodsky JB, Mariano ER: Regional anaesthesia in the obese patient: lost landmarks and evolving ultrasound guidance. Best Pract Res Clin Anaesthesiol 2011; 25: 61-72
  28. Mariano ER, Brodsky JB: Comparison of procedural times for ultrasound-guided perineural catheter insertion in obese and nonobese patients. J Ultrasound Med 2011; 30: 1357-61
  29. Barrington MJ, Kluger R: Ultrasound guidance reduces the risk of local anesthetic systemic toxicity following peripheral nerve blockade. Reg Anesth Pain Med 2013; 38: 289-297

 

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Pay for Performance in Perioperative Pain Management

Costs RocketWe have all heard the “doom and gloom” statistics about rising health care spending, and maybe even some of them have begun to sink in since the roll-out of the Affordable Care Act.

For many reasons, the federal government is working to curb health care expenditures, but many of the processes currently attributed to “Obamacare” have been in the works for a long time.  As an example, the Medicare Modernization Act of 2003 introduced the Inpatient Prospective Payment System; this system encouraged participating hospitals to voluntarily report performance data to avoid payment reductions.  The Deficit Reduction Act of 2005 went further by mandating the development of what we now know as pay-for-performance or value-based purchasing (used interchangeably).

In 2012, the Institute of Medicine published “Best Care at Lower Cost:  the Path to Continuously Learning Health Care in America.”  In this report, recommendation 9 refers to performance transparency:  making data related to “quality, prices and cost, and outcomes of care” available to consumers.

VBPWhat does this mean?  Value-based purchasing in health care is supposed to reward better value, patient outcomes, and innovations – instead of just volume of services (read more).  It is funded by participating institutions based on withholding a set percentage (1.25% currently) of their estimated annual Diagnosis-Related Group (DRG) payments from Center for Medicare and Medicaid Services (CMS).  The percentage is increasing every year and will be 2% by 2017.

VBP2For FY2014, the elements of value-based purchasing have been updated to include the Clinical Process of Care Domain, Patient Experience of Care Domain, and a new Outcomes Domain.  The amount that each of these domains contributes to the eventual DRG payment return at the end of the year is 45%, 30%, and 25%, respectively.  Scores in each domain are calculated based on an institution’s improvement compared to its own historical performance and a comparison against national benchmarks (read more).

The Patient Experience Domain is assessed using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey.  HCAHPS consists of 32 questions, publicly reports its results 4 times a year on http://www.hospitalcompare.hhs.gov, and contains 7 questions that directly or indirectly relate to pain.  For details, please see my previous post “Why We Need Acute Pain Medicine Specialists.”

How do we as anesthesiologists address the need for acute pain medicine physicians and have a positive impact on the patient experience?  We can take the lead in developing multimodal perioperative pain management protocols (1).  For total joint arthroplasty, many of these protocols emphasize opioid-sparing regional anesthesia techniques such as peripheral nerve blocks (PNB) and perineural catheters.  These techniques decrease patients’ reliance on opioids for postoperative pain management and are also associated with fewer opioid-related side effects, better sleep, and higher satisfaction (2).  In addition, greater selectivity in the PNB technique included in a multimodal protocol may even lead to greater functional achievements for total knee arthroplasty (TKA) patients which generates additional value (3).  For more information about TKA perioperative pain management and improving rehabilitation outcomes, please see my previous post “Regional Anesthesia & Rehabilitation Outcomes after Knee Replacement.”

Anesthesiologists can also add value through cost savings for the hospital.  More effective pain management can prevent inadvertent admissions or readmissions due to pain.  In addition, an effective multimodal analgesic protocol can directly or indirectly prevent hospital-acquired conditions (HACs).  HACs are considered by CMS to be “never events” and supposedly preventable (4); hospitals reporting HACs as secondary diagnoses are not entitled to CMS payments for related care.  Examples of HACs include:  urinary and vascular catheter-related infections, surgical site infections, DVT/PE, pressure ulcers, and inpatient falls leading to injury.

Fall riskThere remains substantial controversy related to the potential association between regional anesthesia and inpatient falls (5, 6).  We do know that falls, when they occur, are associated with worse outcomes for patients and higher resource utilization (7) and that falls may occur in lower extremity joint replacement patients with or without PNB (8).  For these reasons, these patients should always be treated as high fall risk, and anesthesiologists can take the lead in developing fall prevention education and fall reduction programs to keep them safe.

In summary, pay for performance in perioperative pain management is already here.  The HCAHPS survey assesses the Patient Experience Domain and can be heavily influenced by the effectiveness of pain management.  There are clear opportunities for anesthesiologists to take an active role in adding value and minimizing risks for surgical patients in the perioperative period.

References:

  1. Hebl JR, Kopp SL, Ali MH, Horlocker TT, Dilger JA, Lennon RL, Williams BA, Hanssen AD, Pagnano MW. A comprehensive anesthesia protocol that emphasizes peripheral nerve blockade for total knee and total hip arthroplasty. J Bone Joint Surg Am 2005;87 Suppl 2:63-70.
  2. Ilfeld BM. Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011;113:904-25.
  3. Mudumbai SC, Kim TE, Howard SK, Workman JJ, Giori N, Woolson S, Ganaway T, King R, Mariano ER. Continuous Adductor Canal Blocks Are Superior to Continuous Femoral Nerve Blocks in Promoting Early Ambulation After TKA. Clinical orthopaedics and related research 2014;472:1377-83.
  4. Hospital-acquired condition (HAC) in acute inpatient payment system (IPPS) hospitals. http://www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/HospitalAcqCond/Downloads/HACFactsheet.pdf
  5. Ilfeld BM, Duke KB, Donohue MC. The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Anesth Analg 2010;111:1552-4.
  6. Memtsoudis SG, Danninger T, Rasul R, Poeran J, Gerner P, Stundner O, Mariano ER, Mazumdar M. Inpatient falls after total knee arthroplasty: the role of anesthesia type and peripheral nerve blocks. Anesthesiology 2014;120:551-63.
  7. Memtsoudis SG, Dy CJ, Ma Y, Chiu YL, Della Valle AG, Mazumdar M. In-hospital patient falls after total joint arthroplasty: incidence, demographics, and risk factors in the United States. The Journal of arthroplasty 2012;27:823-8 e1.
  8. Johnson RL, Kopp SL, Hebl JR, Erwin PJ, Mantilla CB. Falls and major orthopaedic surgery with peripheral nerve blockade: a systematic review and meta-analysis. Br J Anaesth 2013;110:518-28.

 

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Anesthesiology, Healthcare, Medical Education, Pain Medicine, Regional Anesthesiology

Why We Need Acute Pain Medicine Specialists

Not all pain is the same.

Chronic #pain can be palliated. Acute pain must be stamped out.

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PainChronic pain can be palliated, but “acute” pain (new onset, often with an identifiable cause) must be stamped out. This requires a systems-based approach led by physicians dedicated to understanding acute pain pathophysiology and investigating new ways to treat it. The solution is definitely not giving more and more opioids.

As our understanding of pain mechanisms has evolved, select physicians have developed a special focus on pain in the acute injury/illness and perioperative settings that has led to the rapid advancement of systemic and site-specific interventions to effectively manage this type of pain. Acute pain medicine involves the routine use of multiple modalities concurrently (i.e., multimodal analgesia) in the in-hospital setting to reduce the intensity of acute pain and minimize the development of debilitating persistent pain, a problem that can result from even common surgical procedures or trauma. Unfortunately, the need for specialists in acute pain medicine is increasing.

The need for physicians who specialize in acute #pain medicine is increasing.

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In December of 2013, I submitted a 161 page letter to the Accreditation Council for Graduate Medical Education (ACGME) requesting that regional anesthesiology and acute pain medicine be considered for fellowship accreditation with the help of my fellowship director colleagues. The Board of Directors of the ACGME informed me this past fall (2014) that they have approved our fellowship to be the next accredited subspecialty within anesthesiology.

Wait – don’t we already have a fellowship program in pain medicine? Yes we do, and this one year post-residency program does include the “Acute Pain Inpatient Experience.” However, this requirement may be satisfied by documented involvement with a minimum of only 50 new patients and is not the primary emphasis of fellowship training in the specialty. Pain medicine is a board-certified subspecialty of anesthesiology, physical medicine and rehabilitation, and psychiatry and neurology; graduates from any of these residency programs can apply to the one year program. In a recent survey study of practicing pain physicians in the United States with added qualification in pain management according to the American Board of Medical Specialties (ABMS), the great majority (83.7%) of respondents defined their practices as following “chronic pain patients longitudinally” (1).

There is clearly room and a need for a subspecialty training program in acute pain medicine that can focus on improving the in-hospital pain experience. Such a program should advance, in a positive and value-added fashion, the present continuum of training in pain medicine.

HCAHPS Pain QuestionsThe Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey is administered to a random sample of patients who have received inpatient care and receive government insurance through Center for Medicare and Medicaid Services (CMS). The survey consists of 32 questions and is intended to assess the “patient experience of care” domain in the value-based purchasing program. A hospital’s survey scores are publicly disclosed and make up 30% of the formula used to determine how much of its diagnosis-related group payment withholding will be paid by CMS at the end of each year. Of the 32 questions, 7 directly or indirectly relate to in-hospital pain management.

Why should acute pain medicine be a subspecialty of anesthesiology? Anesthesiology is a hospital-based medical specialty, and anesthesiologists are physicians who focus on the prevention and treatment of pain for their patients who undergo surgery, suffer trauma, or present for childbirth on a daily basis. For more details on the role of the anesthesiologist, please see “Physicians specializing in the patient experience.” Further, history supports the evolution of acute pain medicine through anesthesiology. The concept of an anesthesiology-led acute pain management service was described first in 1988 (2), but arguably the techniques employed in modern acute pain medicine and regional anesthesiology date back to Gaston Labat’s publication of Regional Anesthesia: its Technic and Clinical Application in 1922, with advancement and refinement of this subspecialty in the 1960s and 1970s (3-7).

By the time they complete the core residency in anesthesiology today, not all trainees have gained sufficient clinical experience to provide optimal care for the complete spectrum of issues experienced by patients suffering from acutely painful conditions, including the ability to reliably provide advanced interventional techniques proven to be effective in managing pain in the acute setting (8-12). We need physician leaders who can run acute pain medicine teams and design systems to provide individualized, comprehensive, and timely pain management for both medical and surgical patients in the hospital, expeditiously managing requests for assistance when pain intensity levels exceed those set forth in quality standards, or to prevent pain intensity from reaching such levels. The mission statement for the Acute Pain Medicine Special Interest Group within the American Academy of Pain Medicine provides additional justification.

In a survey of fellowship graduates and academic chairs published in 2005, 61 of 132 of academic chairs responded (46%), noting that future staffing models for their department will likely include an average of 2 additional faculty trained in regional anesthesiology and acute pain medicine (13).

Currently, there are over 60 institutions in the United States and Canada that list themselves as having non-accredited fellowship training programs focused on regional anesthesiology and acute pain medicine on the ASRA website. Since 2002, the group of regional anesthesiology and acute pain medicine fellowship directors has been meeting twice yearly at the ASRA Spring Annual Meeting and ASA Annual Meeting which takes place in the fall. Despite not being an ACGME-accredited fellowship, this group, recognizing the lack of formalized training guidelines, voluntarily began to develop such guidelines as the foundation for subspecialty fellowship training in existing and future programs. These guidelines were originally published in Regional Anesthesia and Pain Medicine in 2005 (14), then were subsequently reviewed, revised, and published as the 2nd edition in 2011 (15), and have been recently updated again (16).

As with other subspecialties, acute pain medicine has emerged due to the need for trained specialists—in this case, those who understand the complicated, multi-faceted disease processes of acute pain, and its potential continuity with chronic pain, and can apply appropriate medical and interventional treatment in a timely fashion. The fellowship-trained regional anesthesiologist and acute pain medicine specialist must be capable of collaborating with other healthcare providers in anesthesiology, surgery, medicine, nursing, pharmacy, physical therapy, and more to establish multidisciplinary programs that add value and improve patient care in the hospital setting and beyond.

REFERENCES

  1. Breuer B, Pappagallo M, Tai JY, Portenoy RK: U.S. board-certified pain physician practices: uniformity and census data of their locations. J Pain 2007; 8: 244-50
  2. Ready LB, Oden R, Chadwick HS, Benedetti C, Rooke GA, Caplan R, Wild LM: Development of an anesthesiology-based postoperative pain management service. Anesthesiology 1988; 68: 100-6
  3. Winnie AP, Ramamurthy S, Durrani Z: The inguinal paravascular technic of lumbar plexus anesthesia: the “3-in-1 block”. Anesth Analg 1973; 52: 989-96
  4. Winnie AP, Collins VJ: The Subclavian Perivascular Technique of Brachial Plexus Anesthesia. Anesthesiology 1964; 25: 353-63
  5. Raj PP, Montgomery SJ, Nettles D, Jenkins MT: Infraclavicular brachial plexus block–a new approach. Anesth Analg 1973; 52: 897-904
  6. Raj PP, Parks RI, Watson TD, Jenkins MT: A new single-position supine approach to sciatic-femoral nerve block. Anesth Analg 1975; 54: 489-93
  7. Raj PP, Rosenblatt R, Miller J, Katz RL, Carden E: Dynamics of local-anesthetic compounds in regional anesthesia. Anesth Analg 1977; 56: 110-7
  8. Buvanendran A, Kroin JS: Multimodal analgesia for controlling acute postoperative pain. Curr Opin Anaesthesiol 2009; 22: 588-93
  9. Hebl JR, Dilger JA, Byer DE, Kopp SL, Stevens SR, Pagnano MW, Hanssen AD, Horlocker TT: A pre-emptive multimodal pathway featuring peripheral nerve block improves perioperative outcomes after major orthopedic surgery. Reg Anesth Pain Med 2008; 33: 510-7
  10. Jin F, Chung F: Multimodal analgesia for postoperative pain control. J Clin Anesth 2001; 13: 524-39
  11. Kehlet H, Dahl JB: The value of “multimodal” or “balanced analgesia” in postoperative pain treatment. Anesth Analg 1993; 77: 1048-56
  12. Young A, Buvanendran A: Recent advances in multimodal analgesia. Anesthesiol Clin 2012; 30: 91-100
  13. Neal JM, Kopacz DJ, Liguori GA, Beckman JD, Hargett MJ: The training and careers of regional anesthesia fellows–1983-2002. Reg Anesth Pain Med 2005; 30: 226-32
  14. Hargett MJ, Beckman JD, Liguori GA, Neal JM: Guidelines for regional anesthesia fellowship training. Reg Anesth Pain Med 2005; 30: 218-25
  15. Guidelines for fellowship training in Regional Anesthesiology and Acute Pain Medicine: Second Edition, 2010. Reg Anesth Pain Med 2011; 36: 282-8
  16. Guidelines for fellowship training in Regional Anesthesiology and Acute Pain Medicine: Third Edition, 2014. Reg Anesth Pain Med 2015; 40: 213-7

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