AUTHORS
Alexis LaPietra, DO, FACEP, System Chief for Pain Management and Addiction Medicine, Fellowship Director, Emergency Medicine Pain Management Fellowship and Emergency Medicine Mental Health/Addiction Medicine Fellowship, St. Joseph’s Health, Paterson, NJ
Katherine Vlasica, DO, FACEP, Attending Physician, Director of Emergency Pain Management, St. Joseph’s Health, Paterson, NJ
Sergey M. Motov, MD, Attending Physician and Research Director, Department of Emergency Medicine, Maimonides Medical Center, Brooklyn, NY
PEER REVIEWER
Frank LoVecchio, DO, FACEP, Vice-Chair for Research, Medical Director, Samaritan Regional Poison Control Center, Emergency Medicine Department, Maricopa Medical Center, Phoenix, AZ
The opioid epidemic continues to escalate each year in the United States, and in 2019, drug overdose deaths totaled 70,630, up 4% from 2018.1 During May 2020 to April 2021, the number of drug overdose deaths in the United States exceeded 100,000 during a 12-month period for the first time, with 64% of deaths involving synthetic opioids (mainly illicitly manufactured fentanyl).2 Despite a national focus on recognition, recovery, and treatment of opioid use disorder, the coronavirus-19 (COVID-19) pandemic has had catastrophic effects on strides made to reduce overdose numbers.3 However, there continues to be attention and focus on providing evidence-based opioid-sparing strategies for acute pain. Decreasing unnecessary exposure to opioids may potentially decrease the number of Americans who ultimately experience opioid use disorder.4
Emergency physicians and providers play an important role in addressing the growing opioid epidemic, since one of the most common complaints for an emergency department (ED) visit is pain.5,6 As a specialty, there has been growing interest in using multimodal opioid-sparing strategies through models such as channels-enzymes-receptors targeted analgesia (CERTA) and Alternatives to Opioids (ALTO), which use sub-dissociative ketamine, trigger point injection, intravenous (IV) lidocaine, nitrous oxide, nonsteroidal anti-inflammatory drugs (NSAIDs) with acetaminophen, and ultrasound-guided regional anesthesia, among other modalities, to manage acute pain.7-9 Algorithms such as these allow emergency physicians and providers to continue to provide comprehensive advanced pain management while practicing judicious opioid use.
Nitrous Oxide
Nitrous oxide is a tasteless, colorless gas administered via inhalation, in combination with oxygen via face mask or nasal hood, as an analgesic and anxiolytic agent. It is regulated as a designated medical gas, not a controlled substance, and therefore is under U.S. Food and Drug Administration (FDA) and not Drug Enforcement Administration (DEA) oversight. As per the Food and Drug Administration Safety and Innovation Act (FDASIA) July 2012, nitrous oxide is categorized as an analgesic. The American Dental Association endorses the use of nitrous oxide as a safe practice for managing pain and anxiety during dental intervention.10 There are no fasting requirements or restrictions after single agent gas administration. Additionally, when used as a sole agent for pain or anxiety management, monitoring should include only pulse oximetry; however, when given in combination with opioids, benzodiazepines, or other sedative agents, full cardiopulmonary monitoring is recommended.10 Nitrous oxide has the fastest onset and elimination of all the inhalation agents. The median onset of action and elimination is less than two minutes, making it an ideal agent for pain management and anxiolysis in the ED.11
The maximum percentage of nitrous oxide recommended for administration is 70%, always allowing for a minimum of 30% oxygen administration. The mechanism of action is not fully understood. One prevailing theory is that it works via N-methyl-D-aspartate (NMDA) receptor antagonism for its anesthetic properties but exerts its analgesic effect via endogenous opioid release in the central nervous system.12,13 Additionally, nitrous oxide may exert its analgesic effects by simply reducing anxiety. Patients with significant anxiety and stress are more refractory to pain relief in the ED; therefore, management with medications such as nitrous oxide plays an important role in the overall management of acute pain.14,15
Nitrous oxide has been shown to be an effective agent with multiple indications in both the pediatric and adult emergency medicine population. (See Table 1.) The gas maintains an excellent safety record and has been researched in children as young as 1 year of age.16 The incidence of serious adverse events is rare, and the most common side effects, mostly in the pediatric population, include nausea and vomiting, typically seen with longer administration times and concomitant opioid administration.17-20 There is limited evidence regarding nitrous oxide use as an analgesic in the adult population. However, the available evidence is compelling and illustrates nitrous oxide use as a well-tolerated, safe, and effective analgesic option in reducing acute pain in the prehospital and adult ED setting.21,22 Although nitrous oxide has proven to be overall safe and effective, there are contraindications to its use. (See Table 2.) Emergency clinicians should perform a thorough history and physical exam identifying at-risk patients and determine alternative pain management strategies.
Table 1. Indications for the Use of Nitrous Oxide in the Emergency Department |
|
Table 2. Contraindications to the Use of Nitrous Oxide in the Emergency Department |
|
Trigger Point Injection
Musculoskeletal pain is a common complaint seen in the ED, and trigger point injections (TPI) can be an important part of a multimodal opioid-sparing approach for this type of pain. Trigger points are painful focal areas of hyperirritable muscle spasm that can result from acute trauma, chronic musculoskeletal disorders, or even repetitive microtrauma.23 Patients often present complaining of focal muscular pain or a sore muscle “knot” that may cause radiating pain.24 When palpated, trigger point pain is fully reproducible, and the clinician should feel focal muscle spasm. Trigger point pain does not arise in standardized locations but in any skeletal muscle. The most common muscles involved include the neck and upper, middle, and lower back.23 Although trigger point pain typically is focal, it also can lead to tension headache, torticollis, jaw pain, and tinnitus. Therefore, performing a detailed musculoskeletal exam can reveal the presence of a trigger point as the etiology of the pain.25-27 Overall, a thorough history and physical exam is the most important first step in identification, with one defining criterion being a local twitch response elicited with firm pressure or needle insertion into the trigger point itself.28 There is no standardized laboratory testing or imaging modality necessary for diagnosis.
Trigger point pain can be managed with analgesics, muscle relaxants, and a variety of nonpharmacologic modalities; however, high-quality studies assessing the validity of these modalities are lacking.23,29 TPI is a well-studied and validated modality for the management of trigger point pain by providing immediate targeted relief via direct inactivation of the muscle fibers.23 Equipment necessary for this procedure includes alcohol or chlorhexidine pads, a hollow-bore needle long enough to engage the trigger point, 1-2 cc of local anesthetic, and an adhesive bandage. The needling effect leads to disruption of the spasm and relaxation of the muscle fibers, effectively resolving the pain, while local anesthetic injection serves only to decrease post-needling soreness.30 The most common side effect is vasovagal reaction.31 The patient can be discharged with instructions to stretch, remain active, and avoid strenuous activity for 72 hours. Patients often do not need any additional analgesics.23 Lastly, the only contraindications to TPI are overlying cellulitis at the site of pain, local anesthetic allergy, and patient refusal.
Sub-Dissociative Dose Ketamine
Ketamine, an NMDA receptor antagonist, is one of the most versatile medications in the ED, possessing anesthetic, amnestic, and analgesic properties.32-35
Ketamine administration in low sub-dissociative doses provides effective analgesia with minimal effects on hemodynamics, cognition, or consciousness and can be used for a variety of acute and chronic painful conditions.33,34 Ketamine is rapidly absorbed into systemic circulation after IV, intramuscular (IM), and intranasal (IN) administrations and undergoes extensive hepatic metabolism and then is excreted in the urine.35 Patients with severe liver and renal insufficiency may have prolonged clearance and accumulation of the ketamine metabolites; however, there are no data to imply that sub-dissociative ketamine (SDK) is unsafe in patients with liver or renal dysfunction.36 (See Table 3.)
Table 3. Indications and Contraindications for Ketamine | |
|
Indications |
Contraindications |
|
Acute pain
|
Absolute
|
|
Chronic pain
|
Relative
|
|
Opioid-tolerant pain | |
|
Opioid-induced hyperalgesia | |
Ketamine is both hydrophilic and lipophilic, allowing administration via IV, IM, subcutaneous (SQ), IN, oral (PO), and inhalation; however, IV and IN routes are the most commonly used for sub-dissociative dosing.35 Recommended weight-based dosing is 0.1 mg/kg to 0.3 mg/kg via slow IV push over two to five minutes, or short infusion over 15-30 minutes.37-40 However, it also can be given via a fixed dose of 15 mg to 30 mg over 15 minutes, followed by a continuous infusion starting at 0.1 mg/kg/hr to 0.15 mg/kg/hr.13,41,42 A complete list of dosing options is outlined in Table 4.
Table 4. Routes and Dosing Regimens of Sub-Dissociative Ketamine for Pain Management in the Emergency Department | ||
|
Route |
Dosing |
Comments |
|
Intravenous (IV) |
Weight-based: 0.1 mg/kg to 0.3 mg/kg over 15-30 minutes Fixed: 15 mg to 20 mg over 15-30 minutes Continuous infusion: 0.1 mg/kg/hour to
|
|
|
Intranasal |
0.7 mg/kg to 1 mg/kg |
|
|
Subcutaneous |
Weight-based: 0.1 mg/kg to 0.3 mg/kg Fixed: 15 mg to 20 mg Continuous infusion: 0.1 mg/kg/hour to 0.15 mg/kg/hour |
|
|
Inhalation (nebulization) |
0.75 mg/kg |
|
|
Oral |
0.25 mg/kg to 0.5 mg/kg |
|
Several randomized clinical trials have assessed the analgesic efficacy and safety of IV SDK at 0.1 mg/kg to 0.3 mg/kg as an adjunct to IV morphine. These studies have demonstrated greater analgesic efficacy, up to 120 minutes, with the addition of ketamine compared to morphine alone, but with a higher incidence of dysphoria, dizziness, and lightheadedness.43,44
Numerous high-quality studies have compared SDK at 0.2 mg/kg to 0.5 mg/kg to morphine at 0.1 mg/kg via IV push (IVP) revealing similar analgesic efficacy up to 60 minutes and comparative safety profiles.37,38,45 When given via IVP, SDK can increase the incidence of psycho-perceptual side effects; however, this effect can be reduced, in one study by 40%, if given via slow infusion over 15 minutes.40
Additionally, a lower dose at 0.15 mg/kg via 15-minute infusion was found to provide similar pain relief, no increased need for rescue analgesia, and a lower incidence of adverse effects when compared to a 0.3 mg/kg dose given over 15 minutes.46 (Adverse effects of SDK analgesia are listed in Table 5.) Lastly, several studies have validated the efficacy and safety of continuous ketamine infusion in the management of acute pain via a weight-based dosing regimen of 0.15 mg/kg/hour or via fixed dose of 20 mg/hour for an average duration of infusion of one to four hours. Additionally, both dosing regimens demonstrated significant pain relief with minimal rates of dizziness and fatigue.41,42
Table 5. Commonly Encountered Adverse Effects of Sub-Dissociative Ketamine Analgesia |
|
Intranasal ketamine at 0.5 mg/kg via mucosal atomization device has been shown to significantly reduce pain in adult ED patients.47,48 When compared to typical weight-based dosing of IV morphine (0.1 mg/kg), IN morphine (0.15 mg/kg), and IV fentanyl (1 mcg/kg, IN ketamine (1 mg/kg) has similar pain reduction and onset to analgesia in comparison to the opioid groups.49 Additionally, several clinical studies evaluated and compared analgesic efficacy and safety of ketamine 1 mg/kg IN to both IV morphine 0.1 mg/kg and fentanyl 1 mcg/kg for management of renal colic in the ED and revealed a comparable analgesic efficacy of IN ketamine to both opioids in one trial and lack of analgesic superiority in another two.50-52 Similarly, a study comparing IN ketamine at 1 mg/kg to IV metoclopramide at 10 mg or placebo in ED patients experiencing migraine headache failed to demonstrate analgesic superiority of IN ketamine.53,54
Lastly, a systematic review and meta-analysis of seven randomized trials with 1,760 patients that evaluated analgesic efficacy and safety of IN ketamine compared to parenteral opioids, ketamine, and placebo demonstrated similar pain relief and need for rescue analgesia between all groups at 5-60 minutes and mild and transient adverse effects in ketamine group.55
Ketamine also can be administered via breath-actuated nebulizer (BAN) at a dose of 0.75 mg/kg to 1.5 mg/kg and has been shown to reduce pain (an average of 80% decrease from the baseline to 120 minutes) for acute traumatic and non-traumatic painful conditions.56,57
Additionally, three dosing regimens of ketamine at 0.75 mg/kg, 1 mg/kg, and 1.5 mg/kg administered via BAN have been evaluated in a double-blind clinical trial and revealed similar pain relief among all three groups from 30-120 minutes post-ketamine administration.58
Special Populations
Sub-dissociative dose ketamine can be used in the management of pain in pediatric ED via the IN route with good analgesic response, albeit higher rates of mild and transient adverse effects.59-63 The typical effective dose is 1 mg/kg IN and, when compared to fentanyl 1.5 mcg/kg to 2 mcg/kg IN, pediatric patients have similar pain reduction and need for rescue analgesia but a higher rate of non-serious adverse effects (e.g., bad taste in mouth, sleepiness, and dizziness).63
There are limited data for the use of SDK in the management of chronic pain; however, there are several clinical trials that evaluated the role of SDK in the management of sickle cell crisis pain.64,65 Lastly, ketamine can be used in the prehospital setting via an IV or IN route for management of acute traumatic painful conditions (fractures, dislocations, burns) and in rescue/retrieval situations with similar efficacy to opioids.66-70
Intravenous Lidocaine
Lidocaine is a commonly used local anesthetic possessing anti-inflammatory, analgesic, and immunomodulating effects.71,72 Lidocaine is rapidly absorbed after IV administration and metabolized in the liver to active, but less potent, compounds that are excreted in the kidneys. Renal and hepatic insufficiency leads to accumulation and prolonged half-lives of lidocaine and its metabolites that may lead to neurologic and cardiovascular toxicities.71-74 Lidocaine produces analgesia and anesthesia with a fast onset of action, relatively short half-life, longer duration of action, and a better side effect profile compared to other local anesthetics.71 The role of IV lidocaine for acute pain management initially stemmed from data in patients with chronic neuropathic pain and postoperative pain.73 However, its analgesic properties are continuing to be researched for use in the ED, with a primary focus on the management of renal colic pain.75
Intravenous lidocaine administered as a single agent or as an adjunct to opioids, ketamine, and NSAIDs has been used widely in a variety of acute and chronic painful conditions.72,73 (See Tables 6-8.) Early ED research demonstrated analgesic efficacy and with minimal adverse effects when IV lidocaine was administered as a single agent (1.5 mg/kg dose) in the ED for patients with renal colic.76 Additionally, when compared to IV morphine (0.1 mg/kg), IV lidocaine (1.5 mg/kg) for renal colic pain in the ED was shown to have a greater reduction in pain score at 60 minutes with a similar rate of side effects.77,78
Table 6. Indications and Contraindications to IV Lidocaine Analgesia | |
|
Indications |
Contraindications |
|
Acute pain
|
|
|
Chronic pain
| |
|
Opioid-tolerant pain | |
|
Opioid-induced hyperalgesia | |
Table 7. Side Effects of IV Lidocaine Analgesia |
|
Mild
|
|
Severe
|
Table 8. Intravenous Lidocaine Analgesic Dosing (Single Agent or an Adjunct) | |
|
Dosing |
Comments |
|
Intravenous dosing: Single dose
|
|
|
Intravenous dosing: Continuous infusion
|
|
However, numerous more recently published studies challenged the analgesic efficacy of IV lidocaine in the management of acute pain in the ED. A randomized double-blind clinical trial compared the analgesic efficacy of a combination of lidocaine 1.5 mg/kg IV plus ketorolac 30 mg IV to ketorolac 30 mg IV alone and to lidocaine 1.5 mg/kg IV alone in patients ages 18-64 years presenting to the ED with suspected renal colic. The study demonstrated analgesic inferiority of IV lidocaine alone to ketorolac alone and to a ketorolac/lidocaine combination.79 Similarly, a prospective, randomized, double-blind, placebo-controlled trial of lidocaine 1 mg/kg IV for the treatment of acute migraine in the ED failed to demonstrate analgesic superiority of lidocaine over placebo at 20 minutes post-medication administration.80
Furthermore, a randomized double-blind study of 41 patients ages 18-55 years presenting to the ED with acute radicular low back pain who were to receive either lidocaine 100 mg IV or ketorolac 30 mg IV revealed the ketorolac group had a greater pain reduction and with less rescue medications required.81 Additionally, a study comparing the efficacy and safety of lidocaine 120 mg IV to hydromorphone 1 mg IV for the treatment of acute abdominal pain in the ED revealed superiority of hydromorphone over lidocaine with respect to change in pain score (5 vs. 3.8) and need for rescue analgesia (26% vs. 51%).82 Lastly, a systematic review of eight studies including 536 patients found no definitive evidence to recommend IV lidocaine for managing acute pain in the ED and recommended further research within a larger and older population to assess the efficacy and safety in specific painful syndromes.83
In conclusion, based on the current evidence, IV lidocaine cannot be recommended for routine use in the ED and its administration should be based on a case-by case basis.
Ultrasound-Guided Regional Anesthesia
Ultrasound-guided regional anesthesia (UGRA) has been used in the operating room for decades to provide efficacious pain control using landmark techniques and nerve stimulator-based approaches. As emergency medicine continues to excel in ultrasound-guided procedural skills, UGRA has been adopted quickly into the toolbox as a powerful pain management tool for painful musculoskeletal injuries, laceration repairs, joint reductions, and more.84,85 (See Table 9.)
Table 9. Ultrasound-Guided Regional Anesthesia (UGRA) in the Emergency Department | |||
|
|
Clinical Indications |
Advantages |
Pitfalls |
|
Upper Extremity UGRA | |||
|
Interscalene |
|
|
|
|
Supraclavicular |
|
|
|
|
Infraclavicular |
|
|
|
|
Axillary |
|
|
|
|
Median |
|
|
|
|
Radial |
|
|
|
|
Ulnar |
|
|
|
|
Trunk and Neck | |||
|
Superficial cervical plexus |
|
|
|
|
Serratus anterior plane |
|
|
|
|
Erector spinae |
|
|
(Continued) |
Table 9. Ultrasound-Guided Regional Anesthesia (UGRA) in the Emergency Department (continued) | |||
|
|
Clinical Indications |
Advantages |
Pitfalls |
|
Transversus abdominus plane |
|
|
|
|
External oblique intercoastal block |
|
|
|
|
Pecto-intercoastal fascial block |
|
|
|
|
Lower Extremity | |||
|
Fascia iliaca block |
|
|
|
|
Pericapsular nerve group block (PENG) |
|
|
|
|
Femoral nerve |
|
|
|
|
Sciatic nerve at popliteal fossa |
|
|
|
|
Posterior tibial |
|
|
|
In 2021 the American College of Emergency Physicians (ACEP) released a policy statement endorsing UGRA as a core component of multimodal analgesia and within the scope of practice of emergency physicians.86 Additionally, the American College of Surgeons 2020 guidelines on the management of acute pain in trauma recognizes the importance of regional analgesia as a component of ED pain management and encourages its use as part of a multimodal protocol.87 The advantages of UGRA in the ED go beyond just expeditious pain control and provide benefits ranging from decreased length of stay to preventing nosocomial infections.88 Since its adoption in the ED, UGRA is quickly becoming the standard of care for effective management of painful musculoskeletal injuries as a safe alternative to procedural sedation.89,90 UGRA provides targeted analgesia and is opioid-sparing for an extraordinary range of painful conditions.
Pain management in the trauma patient poses several challenges, with pain management being an understandably low priority during active resuscitation. The intensity of acute pain at the time of injury is the most predictive factor of the development of chronic pain following a traumatic injury, along with older age, comorbidities, obesity, and anxiety.91 As many as 77% of patients who sustain a painful traumatic injury will go on to develop chronic pain, contributing to a significant percentage of disability and decreased functioning in this patient population.
Early research suggested UGRA was an optimal way to provide efficacious quick pain relief preventing the development of chronic pain.92 A more recent 2019 prospective study of 358 injured combat veterans revealed early use of UGRA led to greater pain relief, improved neuropathic pain intensity, and higher satisfaction with pain outcomes at six months post-injury.93 Additionally, studies have shown improved resource utilization obtained through ease of transport, reduced lengths of stay, less monitoring requirements, improved functional outcomes, and decreased costs.89,90,95-97
Geriatric hip fracture pain can present a management dilemma, since providers attempt to balance adequate pain relief with the adverse effects of opioids in this age group. A recent Cochrane review shows that UGRA achieves pain reduction within 30 minutes, reduces the risk of delirium, and allows for quicker mobilization, reducing the risk of chest infections.98 When pain control in UGRA was compared to parenteral administration of morphine, UGRA had a quicker onset of pain control with a larger decrease in pain score.99,100 Additionally, unmanaged pain in the geriatric patient can have deleterious effects on mental status and precipitate delirium. A specific look at hip fracture patients at risk for delirium reveals that early UGRA in the perioperative period reduced the overall incidence of delirium from 23.8% to 10.7%.101
Lastly, use of regional anesthesia in geriatric patients may decrease the amount of parenteral opioids given, thus limiting any resulting untoward side effects.102,103
Pain relief is a core competence for any provider caring for acutely injured children. Most emergency physicians are well versed in administration of parenteral analgesia and sedation for painful injuries; however, there is a dearth of literature and training possibilities for UGRA in the pediatric population. Nevertheless, there are data showing that UGRA in the pediatric patient is a safe and effective intervention in treating many types of injuries, including fracture and dislocation reduction, foreign body removal, drainage of abscesses, and laceration repair. A large review of more than 100,000 blocks done by the Pediatric Regional Anesthesia Network shows the risk of local anesthetic systemic toxicity to be 0.7 in 10,000 patients, with no reported permanent neurologic deficits, and the rate of transient neurologic deficit was 2.4 in 10,000.104 Regional anesthesia for pediatric femur fracture was successful in providing better pain control when compared to systemic analgesics with no adverse effects, longer analgesia, less systemic morphine, and fewer nursing interventions.94,105,106 UGRA also is safe and effective in pediatrics for the management of closed reduction of forearm fractures, lower extremity lacerations, and foreign body removal.107-109
The emergency medicine application of regional anesthesia is rapidly expanding as more novel blocks are introduced. The superficial cervical plexus blocks, initially used for neck procedures in the cape distribution, can be used by ED providers for clavicle fracture pain management, central line placement, and neck laceration repairs.110,111
Serratus anterior plane blocks are safe and extremely effective for more than rib fractures and thoracotomy pain, as literature emerges regarding their role in the management of thoracostomy tube insertion and pain related to herpes zoster.112-114 Erector spinae blocks provide excellent analgesia for chest wall trauma, zoster-related pain, transverse process fracture, pancreatitis, renal colic, and appendicitis.115-119 Pericapsular nerve group blocks can provide relief related to intracapsular hip fractures, with the main advantages being ease of performance, distance of landmarks from neurovascular bundle, and preservation of motor function.120-122
Despite the proven benefit of UGRA, 52% of emergency medicine residencies offer no training in UGRA, and only 7% of academic emergency departments have credentialing pathways in place for attending physicians. The UGRA utilization gaps are a result of little formal training in ED faculty, interdepartmental politics, and perceived difficulty of the procedure.123,124 Simulation and cadaver labs are effective tools for UGRA education but were not found to be widely used in emergency medicine training programs.124 However, once a basic level of manual dexterity in UGRA is achieved, physicians rapidly expand their block repertoire from basic blocks to more advanced techniques.125,126
Complications of UGRA
Providers must be aware of the complications associated with UGRA. The most concerning include local anesthetic systemic toxicity (LAST), nerve injury, and delayed recognition of acute compartment syndrome. Local anesthetic systemic toxicity risk can be reduced with use of ultrasound guidance, calculation of maximum/ lowest effective dose, aspiration before injection, hydrolocation of structures with sterile saline, and cardiac monitoring.127-130
Peripheral nerve injury is rare, occurring in 16.8/1,000 blocks, and permanent paresthesia occurring in 3-8/10,000 performed blocks.131-133 The majority of the cases of neuropraxia resolve and may be avoided by using lower concentrations of local anesthetic, pressure monitoring, good visualization of needle tip, and avoidance of over-sedating patients during the block.
Lastly, the use of ultrasound in periclavicular regional anesthesia has markedly decreased the rates of pneumothorax to 0.06%.134 Acute compartment syndrome is seen most commonly in tibial shaft and distal radius fracture, and early recognition is paramount.135,136
There is continued debate in the literature regarding the safety of UGRA out of concern that early signs of progression will be masked. The ACS National Surgical Quality Improvement Project showed no difference of postoperative complications between UGRA and general anesthesia groups in 18,000 patients with lower extremity trauma.137 Another cohort of 565 pediatric upper extremity trauma cases did not detect any acute compartment syndrome cases masked by use of UGRA.138 Both the European Society of Regional Anaesthesia and Pain Therapy and American Society of Regional Anesthesia and Pain Medicine acknowledge the lack of data and have given guidelines for cautious use of UGRA in the setting of trauma.139
Best practices in using UGRA in patients at high risk for compartment syndrome include the use of dilute concentrations of local anesthetics and avoidance of additives, careful monitoring of high-risk patients for disproportionate pain or pain away from the site of injury, paresthesias that are beyond the lifespan of the local anesthetic, and pain on passive movement of limb. A sudden increase in pain should always be seen as compartment syndrome unless proven otherwise.139,136 While the masking of acute compartment syndrome remains a possibility in UGRA, diligent clinical and pressure monitoring and frequent neurovascular exams should allow for safe use.
Multimodal Nonopioid Analgesia
Multimodal nonopioid combinations, such as NSAIDs plus acetaminophen, work synergistically and frequently are administered together in the ED because of their efficacy in managing musculoskeletal and soft tissue pain.140,141 There has been robust interest in identifying the best dosages and combinations of nonopioid analgesics for acute musculoskeletal pain and acute low back pain in an effort to reduce unnecessary exposure to opioids. Ibuprofen (400 mg) and acetaminophen (1,000 mg) given together the ED was not more effective in managing pain or improving function in acute musculoskeletal pain.142,143 Additionally, this same combination was not superior to acetaminophen alone in managing the pain associated with acute musculoskeletal trauma in the ED.144 Furthermore, when evaluating the efficacy of ibuprofen/acetaminophen, oxycodone/acetaminophen, hydrocodone/acetaminophen, and codeine/acetaminophen, no one combination was superior in the management of acute musculoskeletal and fracture pain in the ED.145
When looking specifically at the management of acute low back pain, naprosyn was as effective alone as when given in combination with placebo, oxycodone/acetaminophen, or cyclobenzaprine.146 Lastly, there was no difference in the efficacy of ibuprofen alone, acetaminophen alone, or a combination of the two when given for acute soft tissue injury pain.147 Therefore, whenever possible, opioid combinations should be avoided in an effort to decrease unnecessary exposure and potential progression to misuse or abuse, and instead nonopioid combinations should be used.
Topical Lidocaine Patch
Topical lidocaine has been shown to be effective in managing the pain associated with diabetic neuropathy, herpetic neuralgia, osteoarthritis, and acute low back pain.148,149 The topical 5% patch is easy to use and should be applied directly over the site of pain except in patients with an allergy to amide anesthetics, active eczema, or open wounds. The most common side effects include local burning, edema, or erythema at the application site.148,149 Patients can apply between one and three lidocaine 5% patches at the site of pain, keeping them in place for no more than 12 hours so as to have a 12-hour patch-free period per day.148 One of the major barriers is the cost of the lidocaine 5% patches, which can range from $45 to $150 per pack of six.150,151 However, a suitable solution may be over-the-counter lidocaine 4% patches, which cost between $6 and $12 per pack of six and were found to be noninferior to the 5% version in pain reduction and adverse effects.150,151
Conclusion
Acute pain management in the ED continues to be challenging. However, the recent advances made using alternative nonopioid medications and modalities provide practitioners with multiple safe and effective options for addressing pain. Although opioids will always play an important role in acute pain management, they should be reserved for severe, uncontrolled pain, end-of-life pain management, cancer pain, and refractory pain. Nonopioid alternatives should be what clinicians reach for as a first in addressing the source of patients’ pain. Nitrous oxide allows practitioners to perform painful procedures with significantly decreased pain and anxiety with minimal to no side effects as well as minimal monitoring in most cases. Acute focal musculoskeletal spasm can be treated with a trigger point injection providing safe and effective pain relief at the bedside. Although IV lidocaine was a compelling option for pain management in the ED, more research is needed to determine to appropriate indications and dosing. The use of sub-dissociative ketamine has gained popularity in the management of acute severe pain with an opioid-sparing component. Although ketamine may have a minor transient increase in adverse effects on perception, this can be mitigated with lower initial dosing, and administration via a slow infusion or the intranasal route.
An actively growing area of interest and expertise in emergency medicine is ultrasound-guided regional anesthesia. It has been revealed as an extremely effective and important modality in management of acute traumatic pain. It has multiple patient-centered benefits as well as decreased length of stay because of improved early mobilization. Overall, UGRA is quickly emerging as staple in the ED and may quickly become standard of care. Medicine combinations, as well as single-agent use of NSAIDs and/or acetaminophen, continue to be a focus in the management of acute musculoskeletal pain. There is no clear benefit found in adding opioids or muscle relaxants to NSAIDs or acetaminophen. Additionally, opioid combinations, such as oxyocodone/acetaminophen or hydrocodone/acetaminophen, are no more effective than an ibuprofen/acetaminophen combination for this type of pain. The current evidence supports use of NSAIDs alone as the most effective method for managing acute musculoskeletal and soft tissue injury pain.
As research and education related to opioid-sparing strategies in the management of acute pain continues, the hope is that pain management in the ED will rely less and less on opioids for the successful relief of mild to moderate pain, thus decreasing unnecessary opioid exposure and, ultimately, the potential for addiction.
REFERENCES
A full list of references is available online: https://bit.ly/32h1e43
Acute pain management in the emergency department continues to be challenging. However, the recent advances made using alternative nonopioid medications and modalities provide practitioners with multiple safe and effective options for addressing pain.
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