A c u t e Pa i n Ma n a g e m e n t David M. Dickerson,

MD

KEYWORDS  Acute pain management  Multimodal analgesia  Multimodal pain management  Ambulatory surgery  Outpatient surgery KEY POINTS  The cost to the patient and society of uncontrolled postoperative pain and chronic postsurgical pain requires a focus on prevention and effective multimodal intervention.  The ambulatory anesthesiologist should be skilled at regional anesthesia and the application of continuous peripheral nerve catheters.  The ambulatory surgical setting should make these techniques and their implementation possible.  Effective communication in the perioperative period among the patient, nursing staff, and providers is necessary for rapid assessment and treatment of a patient’s pain.  The cost of maintaining a formulary with multiple analgesic drug classes and supplies and equipment for regional anesthesia may be offset by revenue in an outcomes-based reimbursement model.

INTRODUCTION

Acute postsurgical pain poses treatment challenges for the anesthesiologist, challenges augmented by the ambulatory surgical setting. The “fifth vital sign,” pain, has become a focal point and continues to be a primary determinant of delayed discharge, unanticipated admission, and quality of recovery.1–5 Although the prevalence of uncontrolled postoperative pain, frequently moderate to severe, has been characterized, the continued cost of uncontrolled pain has led to publication of practice guidelines for its control.6 Most recently, the American Society of Anesthesiologists practice guidelines for acute pain management establish a paradigm for the more frequent and specific use of multimodal analgesia (MMA) (Table 1).7 This article updates acute pain management in ambulatory surgery and proposes a practical three-step approach, the “three I’s” (Box 1), for reducing the impact and incidence of uncontrolled surgical pain. By identifying at-risk patients, implementing MMA, and intervening promptly with rescue therapies, the anesthesiologist may

Disclosure: No conflicts or relationships to disclose. Department of Anesthesia and Critical Care, University of Chicago Medicine, 5841 South Maryland Avenue MC4028, Office O-416, Chicago, IL 60637, USA E-mail address: [email protected] Anesthesiology Clin - (2014) -–http://dx.doi.org/10.1016/j.anclin.2014.02.010 anesthesiology.theclinics.com 1932-2275/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.

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Table 1 American Society of Anesthesiologists practice guidelines for acute pain management in the perioperative setting Recommendations Institutional policies

 Anesthesiologists should provide ongoing, up-to-date education and training on the safe and effective use of available treatment options within the institution. Including:  Basic bedside pain assessment  Nonpharmacologic techniques  Sophisticated pain management techniques (eg, regional anesthesia)  Providers should use standardized, validated instruments for the regular evaluation and documentation of pain intensity, therapeutic response, and side effects.  Anesthesiologists responsible for perioperative analgesia should be available at all times to assist in the evaluation and treatment of perioperative pain.  Standardized, institutional policies and procedures should be developed and an integrated approach used for pain management by an anesthesiologist-led acute pain service.

Preoperative  A directed pain history, directed physical examination, and pain control preparation plan should be included in the anesthetic preoperative evaluation. of the patient Perioperative techniques

 Anesthesiologists who manage perioperative pain should use therapeutic options, such as central regional opioids, systemic opioid PCA, or peripheral regional techniques after an analysis of the risk/benefit ratio for the individual patient.  The therapy implemented should reflect the individual anesthesiologist’s expertise and a respect for the capacity for safe application of the modality in the specific practice setting. This includes the ability to recognize and treat adverse effects from the therapy.

Multimodal techniques for pain management

 Whenever possible, anesthesiologists should use multimodal pain management therapy, regional block should be considered.  Unless contraindicated, patients should receive an around-the-clock regimen of COXIBs, NSAIDS, or acetaminophen.  Dosing regimens should optimize efficacy and minimize adverse events.  Specific medication, dose, route, and duration of therapy should be individualized.

Abbreviations: COXIB, cyclooxygenase-2 inhibitor; NSAID, nonsteroidal anti-inflammatory drugs; PCA, Patient-Controlled Analgesia. Adapted from American Society of Anesthesiologists Task Force on Acute Pain Management. Practice guidelines for acute pain management in the perioperative setting. Anesthesiology 2012;116:255–6; with permission.

Box 1 Planning for pain: the three “I’s” Identify patients at risk for uncontrolled postoperative pain Implement effective preventative multimodal analgesia Intervene with rescue regional analgesia, additional opioids, or nonopioid agents

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improve outcomes, reduce cost, and optimize the patient’s experience and quality of recovery. IDENTIFY: RISK STRATIFICATION, PREPROCEDURAL PLANNING

The preanesthetic assessment identifies a history of uncontrolled postsurgical pain, intolerance or contraindications to analgesics, contraindications to regional anesthesia, and presence of preoperative pain or anxiety.7 Several patient and surgical characteristics predispose to moderate or severe postoperative pain (Box 2).8–12 Identifying a high-risk cohort preoperatively warrants prompt initiation of MMA. Comprehensive MMA may impact the patient’s quality of recovery, prevent discharge delay or unanticipated admission, and reduce the risk of chronic postsurgical pain (Box 3).13–22 Katz23 suggested controlling pain throughout all phases of the perioperative period and not just the period of surgical intervention.24 Uncontrolled postdischarge pain can lead to unanticipated admission, defined as readmission within 24 hours of surgery, and greater risk for chronic postsurgical pain. For these reasons, the anesthesiologist should assist the surgical team in planning postdischarge multimodal analgesic regimens for the most immediate and intense period of surgical pain. Appreciation of the multitude of neural pathways involved in nociceptive afferent neurotransmission is the foundation for a targeted, comprehensive multimodal approach (Table 2). Preoperative blocking of the afferent injury barrage during and after surgery prevents the induction of central sensitization, lowering postoperative pain and analgesic requirements. IMPLEMENT: MMA, REGIONAL ANESTHESIA

Multiple days of effective analgesia minimizing adverse effects can be accomplished with continuous peripheral neural blockade (cPNB). A single-shot PNB reduces opioid exposure, improves patient comfort and circulation to the anesthetized extremity, reduces time in recovery, increases patient satisfaction, and lowers rates of adverse events.25 Catheter-based continuous techniques have similar benefit.4,26 Compared with single-shot PNBs, cPNBs are associated with better pain control and the need for decreased opioid analgesics, resulting in less nausea. Chronic pain after surgery

Box 2 Preoperative predictors of moderate-to-severe postoperative pain  Increased preoperative pain  Increased preoperative anxiety  Younger patients  Female gender  Surgery type  Appendectomy  Cholecystectomy  Hemorrhoidectomy  Tonsillectomy  Duration of surgery

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Box 3 Preoperative predictors of the development of chronic postsurgical pain  Increased preoperative pain  Increased preoperative anxiety  Increased postoperative pain  Female gender  Surgical type

also is decreased and patient satisfaction is augmented.27,28 cPNBs can be safely placed at multiple sites with proved analgesic efficacy for a multitude of ambulatory surgeries (Table 3).29 The cost and risks of these techniques must be weighed in the context of the benefit to the patient during the first postoperative days. Some

Table 2 Pathway approach to multimodal analgesia Peripheral vs Central Nervous Site of Action

Analgesic Agent

Receptor Target

Peripheral afferent blockade, inhibition of central hyperexcitability

Peripheral 1/ central

Local anesthetic (wound infiltration)

Sodium channel (free nerve endings of peripheral) Sodium channel (peripheral afferent neuron) Sodium channel (central and peripheral)

Inflammation reduction (reduction in proinflammatory mediators, decreased afferent neurotransmission)

Peripheral and central

Afferent slowing

Local anesthetic (peripheral nerve block) Local anesthetic systemic infusion Acetaminophen, paracetamol NSAIDs Dexamethasone

Cox-II, cannabinoid

Peripheral and central

Gabapentanoids (Lyrica, gabapentin)

Calcium-channel

Spinal and supraspinal modulation

Central

Opioids

Opioid receptors

Antinociceptive interneuron activation

Membrane stabilization

Benzodiazepines SNRI/TCA (chronic use)

GABAa Norepinephrine reuptake, serotonin reuptake

Pronociceptive interneuron blockade

Central (dorsal horn of spinal cord)

Ketamine, dextromethorphan, levorphanol, methadone

NMDA receptor

Descending inhibition

Central

Tizanidine, clonidine, dexmedatomidine

Alpha-2 in locus ceruleus

Cox-I, Cox-II Cox-II

Abbreviations: Cox, cyclooxygenase; GABA, g-aminobutyric acid; NMDA, N-methyl-D-aspartate; NSAID, nonsteroidal anti-inflammatory drugs; SNRI, selective norepinephrine reuptake inhibitor; TCA, tricyclic antidepressant.

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Table 3 Indications for continuous nerve blocks in orthopedic procedures and trauma Doses for Initial Bolus Followed by Continuous Infusion

Surgical Procedure or Site of Injury

Continuous Block

Total shoulder arthroplasty, shoulder hemiarthroplasty, rotator cuff repair, shoulder arthrodesis, “frozen” shoulder physical therapy, biceps surgery, proximal humerus fractures

Interscalene

20 mL ropivacaine 0.5% 5–10 mL$h 1 ropivacaine 0.2%

Distal humerus fractures, elbow arthroplasty, elbow arthrodesis, radius fractures and surgery, ulna fractures and surgery, wrist arthrodesis, reimplantation surgery

Supraclavicular, infraclavicular, axillary

20 mL ropivacaine 0.5% 5–10 mL$h 1 ropivacaine 0.2%

Breast surgery

Thoracic paravertebral (T4-5)

15 mL ropivacaine 0.5% via catheter 5–10 mL$h 1 ropivacaine 0.2% via catheter

Total knee arthroplasty, anterior cruciate ligament reconstruction, patella repair, knee active and passive physical therapy

Femoral nerve

20 mL ropivacaine 0.5% 5–10 mL$h 1 ropivacaine 0.2%

Total knee arthroplasty, posterior cruciate ligament reconstruction

Femoral 1 sciatic

6–12 mL ropivacaine 0.2%–0.5% 3–8 mL$h 1 ropivacaine 0.1%–0.2%

Tibia fracture and repair, fibular fracture and repair, ankle fusion, subtalar fusion, total knee arthroplasty, hallux valgus repair

Sciatic or popliteal

5–10 mL ropivacaine 0.2%–0.5% 3–8 mL$h 1 ropivacaine 0.1%–0.2%

Ankle fusion, total ankle arthroplasty

Femoral or saphenous 1 sciatic

20 mL ropivacaine 0.2% 5–10 mL$h 1 ropivacaine 0.1%

Adapted from Chelly JE, Ghisi D, Fanelli A. Continuous peripheral nerve blocks in acute pain management. Br J Anaesth 2010;105(Suppl 1):i88; with permission.

procedures and patients, however, are not suitable for regional anesthesia because of contraindication or surgical site. These patients should still receive local anesthetic infiltration at incision sites. IMPLEMENT: MMA, PHARMACOTHERAPY

Much emphasis has been placed on MMA to improve the quality of recovery, decrease length of postanesthesia care unit stay, and potentially reduce the opioid requirement.1–3,30–33 Opioid-sparing methods help to reduce delayed discharge, prevent unanticipated admission, and potentially alter the rates of cancer recurrence or metastasis.34–36 The American Society of Anesthesiologists practice guidelines provide a framework for incorporating nonopioid medications perioperatively.7 The selection of the type and number of specific nonopioid agents should be evidence-based and directed toward minimizing risk and maximizing benefit. Several studies support preoperative initiation of nonsteroidal anti-inflammatory drugs (NSAIDs), yet the necessary dose, route, frequency, and duration are unclear. The potent inhibition of prostaglandin synthesis by NSAID therapy may have analgesic

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benefits that must be weighed against the potential renal, cardiovascular, gastrointestinal, and bleeding risks.37–39 Whether or not NSAIDs impair bone healing is controversial.40 Among its potent antiemetic effects, dexamethasone also may contribute to postoperative pain relief and reduce opioid consumption.41,42 a2-Agonists, ketamine, b-blockers, local anesthetics, and acetaminophen can improve postoperative pain management (see Table 1).43–50 When acetaminophen and an NSAID were combined, the benefit was synergistic. When not contraindicated, these agents should be administered concurrently for maximal benefit.51 The efficacy of preoperative gabapentinoids in reducing postoperative pain has been evaluated in randomized controlled trials and meta-analyses. Most studies demonstrated a reduction in postoperative pain scores, but there was discrepancy in the reduction of opioid consumption; postoperative nausea and vomiting; and other adverse effects, such as sedation, dizziness, or visual disturbances.52–55 Because preoperative anxiety correlates with severe postoperative pain, anxiolysis may be another target for intervention. A 1200-mg dose of gabapentin significantly reduced preoperative anxiety and pain catastrophization in highly anxious patients compared with placebo.56 In a recent, randomized, double-blind study, preoperative coadministration of midazolam and diclofenac resulted in significant reduction of pain scores and postoperative nausea and vomiting compared with diclofenac alone for hernia repair surgery performed with general anesthesia.57 IMPLEMENT: NONPHARMACOLOGIC TECHNIQUES

Nonpharmacologic techniques may influence patient stress, anxiety, and pain. Intraoperative music has been shown to reduce opioid consumption and increase patient comfort after gynecologic surgery.58 Transcutaneous electrical nerve stimulation and other complementary therapies offer additional patient comfort.59 INTERVENE: RECOVERY ROOM RESCUE

If preoperative and intraoperative interventions fail to produce patient comfort, the anesthesiologist must first rule out superimposed medical issues in a timely fashion (eg, anginal chest pain, pneumoperitoneum-related shoulder or abdominal pain). Assuming surgical pain, the anesthesiologist must implement a treatment algorithm to promptly intervene in hopes of improving the patient’s comfort and preventing potential discharge delay or admission. Application of other classes or doses of nonopioid analgesics and additional opioids should be initiated while the possible need for a neuraxial block is evaluated. SUMMARY

The cost to the patient and society of uncontrolled postoperative pain and chronic postsurgical pain requires a focus on prevention and effective intervention. The ambulatory anesthesiologist should be skilled at regional anesthesia and the application of continuous peripheral nerve catheters. The ambulatory surgical setting should make these techniques and their implementation possible. For rapid assessment and treatment of a patient’s pain, communication in the perioperative period among the patient, nursing staff, and providers is necessary. The cost of maintaining a formulary with multiple analgesic drug classes and supplies and equipment for regional anesthesia may be offset by revenue in an outcomes-based reimbursement model.

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