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Pain Management 

Pain Management
Chapter:
Pain Management
Author(s):

Elisha Waldman

and Stefan J. Friedrichsdorf

DOI:
10.1093/med/9780190066529.003.0004
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date: 27 September 2020

Introduction

Although palliative care involves much more than just pain treatment, effective analgesia is nonetheless a critical part of such care. This will be an adjunct to management of the underlying condition, regardless of whether definitive treatment is available or not, and is also essential in the management of acute trauma. In fact, if pain is not well managed, it may not be possible to determine the underlying condition added to the devastating impact of unrelieved acute and chronic pain on the individual, family, and healthcare workers. As noted in earlier chapters, appropriate pain treatment and alleviation of suffering should be viewed as a human right and as part of any comprehensive care plan, regardless of likelihood of survival.

Pain may be roughly categorized as acute, chronic, acute-on-chronic, or procedural. Chronic pain may also be classified as a subtype of pain that travels through undamaged pain pathways (nociceptive) and through damaged pathways (neuropathic). Beyond the scope of this chapter (but discussed in Chapter 16) is also the concept of total pain and various types of emotional, psychological, and existential suffering; assessment and management of the holistic needs of a person and family are nonetheless essential. Indeed, in a post-trauma situation it may be that physical chronic pain has causes that are strongly related to the nonphysical trauma, and both must be addressed. Thus assessment must include awareness of social, cultural, psychological, and spiritual issues, including awareness of mental health needs and the roles that fear, anxiety, and exposure to violence, such as rape or witnessing killing, may have on the experience and expression of pain.

Pain management and palliative care require a multidisciplinary approach. As noted in elsewhere in this manual, whenever possible, local resources for pain management as well as for psychosocial support should be identified and included in planning and management of the healthcare response.

Proper pain treatment requires first and foremost access to necessary medications and equipment. These are covered in Chapter 13 in this book. In addition to having the means for treating pain at hand, in order to arrive at an appropriate treatment plan it is also important, through careful history-taking and examination, to identify the degree and type of pain a patient may be experiencing. This may be especially challenging in the context of a humanitarian crisis, where there may be significant language and cultural barriers and it may be difficult to discern chronic from acute pain.

Regardless of the type of pain and the likelihood of patient survival, in order to achieve ongoing control of pain, clinicians should strive to arrive at a carefully considered individualized pain plan that may involve a combination of medications as well as integrative (nonpharmacological) interventions.

Pain Assessment

Assessing the type and degree of pain is of course easiest when one is faced with a calm, oriented, and verbal patient. In such a situation through careful history-taking and examination one may quickly arrive at an assessment of pain needs. Careful attention should be paid to nonverbal cues, such as facial expression, body position, and vital signs. This pain history will include the site of the pain (there may be several), the severity, how the pain moves, when it comes on, what words are used to describe the pain such as burning or stabbing, and anything that help relieves the pain or makes it better. To aid assessment a number of report measures have been widely validated to help gauge the severity of the pain and pain relief. Some of the more detailed formats, such as the Brief Pain Inventory questionnaire, may be impractical in emergency situations. More widely used are visual analogue scales (commonly used with both adults and children) or numerical rating scales, for example rating one’s pain on a scale from 0 to 10 with 10 being the worst pain imaginable.

Infants and small children, as well as nonverbal adults, are at particular risk for underappreciation and undertreatment of pain (see Chapter 12).When possible, parents or caregivers who know the child should be asked for their sense of a child’s pain. In addition, for neonates, infants, or children with neurological impairment one may use the Revised-Face, Leg, Activity, Cry, Consolability (r-FLACC) scale.

Multidimensional Observational Rating Scales

For nonverbal patients and children younger than 4 years, pain is measured using observation rating scales. Examples include the following:

  • Infants: Infant FLACC scale (see Table 4.1)1

  • Toddlers, older nonverbal children: FLACC pain scale (0–10)2

  • Nonverbal, intellectually impaired persons: r-FLACC (see Box 4.1)3

Table 4.1. Infant FLACC Scale

Infant FLACC Scale

Category

Scoring

Face

No particular expression or smile

Occasional grimace or frown, withdrawn, disinterested

Frequent to constant quivering chin, clenched jaw

Legs

Normal position or relaxed

Uneasy, restless, tense

Kicking or legs drawn up

Activity

Lying quietly, normal position, moves easily

Squirming, shifting back and forth, tense

Arched, rigid, or jerking

Cry

No cry (awake or asleep)

Moans or whimpers, occasional complaint

Crying steadily, screams or sobs, frequent complaints

Consolability

Content, relaxed

Reassured by occasional touching, hugging or being talked to, distracted

Difficult to console or comfort

Instructions: Each of the five categories is scored from 0 to 2, which results in a total score between 0 and 10.

Source: From Merkel, Voepel-Lewis, and Malviya (2002).

From Malviya et al. (2006). © Wiley. Reprinted with permission.

Self-Assessment

  • 4- to 6-year-olds: Simplified Faces Pain Scale (S-FPS) or Simplified Concrete Ordinal Scale (S-COS) (see Fig. 4.1)4

  • 6- to 12-year-olds: Faces Pain Scale–revised (see Fig. 4.2)5

  • Individuals >10 years of age: Visual Analogue Scale (VAS) (see Fig. 4.3)6 or Numerical Rating Scale (NRS-11) (see Fig. 4.4)7

Figure 4.1. Simplified Faces Pain Scale (S-FPS) or Simplified Concrete Ordinal Scale (S-COS) for 4- to 6-year-old children. Instructions: Ask the child whether or not they are in pain. If yes, show faces or building blocks to evaluate for “mild,” “medium,” or “severe” pain.

Figure 4.1. Simplified Faces Pain Scale (S-FPS) or Simplified Concrete Ordinal Scale (S-COS) for 4- to 6-year-old children. Instructions: Ask the child whether or not they are in pain. If yes, show faces or building blocks to evaluate for “mild,” “medium,” or “severe” pain.

(Reprinted from Emmott, West, et al., 2017, with permission from Elsevier.)

Figure 4.2. Faces Pain Scale–Revised (FPS-R) for children age 7 years and older. The instructions, and translations into more than 60 languages, are available at: http://www.iasp-pain.org/Education/Content.aspx?ItemNumber=1519.

Figure 4.2. Faces Pain Scale–Revised (FPS-R) for children age 7 years and older. The instructions, and translations into more than 60 languages, are available at: http://www.iasp-pain.org/Education/Content.aspx?ItemNumber=1519.

(Reprinted with permission from Hicks, von Baeyer, et al., 2001.)

Figure 4.3. Visual Analogue Scale (VAS).

Figure 4.3. Visual Analogue Scale (VAS).

(Reprinted with permission from Bailey, Gravel, et al., 2012.)

Figure 4.4. Numerical Rating Scale (NRS-11).

Figure 4.4. Numerical Rating Scale (NRS-11).

(Reprinted with permission from von Baeyer, Spagrud, et al., 2009.)

Assessment should, of course, be an ongoing undertaking, and patients, regardless of triage status, should be regularly re-evaluated for improvement or worsening of pain and the impact of any interventions.

Treatment of Pain

Having assessed the pain, one may formulate an individualized pain plan for a given patient. A plan should include selection of appropriate medications with an appropriate administration schedule, selection of an appropriate route, and ongoing re-evaluation and adjustment as dictated by the patient’s needs. Although this may sound self-evident, the principles laid out here are critical for achieving good pain control; pain management cannot be viewed as a one-time, one-dose procedure.

Route and timing are important issues. Some medications may be available only in intravenous or enteral forms, and, conversely, some patients may be unable to take enteral or intravenous forms. Thus careful consideration must be given in choosing enteral (oral, sublingual, rectal), intravenous, subcutaneous, or topical or transdermal routes.

In addition, medications should not be given as one-time doses. The aim is to keep the patient pain-free regardless of whether the pain is acute or chronic. To do this, medications should be prescribed “by the clock” or by regular administration (e.g., oral morphine is normally scheduled every 4 hours) with frequent re-evaluation and titration as dictated by the clinical situation. As-needed (PRN) orders alone (i.e., without scheduled analgesia) cannot be recommended, as the end result is often that no medication is given at all. However, PRN medication may be scheduled in addition to the regular dose, to manage rescue or breakthrough pain, which is pain occurring in between the regular dosing. This dose can be calculated in different ways, but a simple way is to use the following formula, which works for both children and adults:

Example: for a child (10 kg) with severe acute pain: Oral morphine 0.3 mg × 10 kg = 3 mg every 4 hours. Additional breakthrough (PRN or “rescue” dose) would be 10% of the daily total dose (3 mg every 4 hours = 18 mg/day), or 1.8 mg every 1–2 hours as needed.

For a detailed list of essential medications, along with routes and dosing, please see Chapter 13. In general, pain medications can be divided into three classes: nonopioids, opioids, and adjuvants. In addition, we will briefly touch on here integrative and nonpharmacological therapies. It is important to note that good pain management usually requires a combination of approaches, particularly when the pain is severe. Regardless of type and quality of pain, a rational, stepwise approach to managing pain, including escalation of dosage and class of drug when necessary, is central to quality care (see Box 4.2 at the end of the chapter for a sample algorithm).

bid, twice daily; GI, gastrointestinal; IM, intramuscular; IV, intravenous; NSAID, nonsteroidal anti-inflammatory drug; PO, oral; PR, rectal; qhs, every bedtime; SC, subcutaneous; SL, sublingual; tid, three times daily.

Basic Analgesics

This category includes paracetamol (acetaminophen), ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs), which may be suitable for milder pain. These agents also play a role in conjunction with opioids for more severe pain and may provide additional benefits depending on the clinical scenario, such as antipyretic activity.

Opioid Analgesics

This category includes weak opioids such as tramadol as well as strong opioids such as morphine, fentanyl, hydromorphone, and methadone. Codeine, a weak opioid and a prodrug in its administered form, is no longer widely used because of concerns about unpredictable metabolism leading to both undertreatment and unexpected adverse events. We would therefore recommend against its use, although, of course, if this is the only agent available and there are no other options, clinicians may exercise judgment based on the clinical setting.

The choice of opioid may depend heavily on availability. In general, if there is a clinical suspicion of renal impairment, fentanyl or methadone may be preferable, owing to concerns about toxic accumulation of metabolites of morphine and hydromorphone in this setting. If morphine or hydromorphone are used in the setting of renal failure, clinicians should remain alert to the risk of metabolites building up, leading to myoclonus (often misinterpreted as discomfort) and seizures.

Other side effects of opioids that clinicians should remain aware of and that may complicate the clinical picture are constipation and drowsiness (which tends to pass after the first day or so, and often represents patients simply catching up on sleep now that their pain is being adequately managed). Urinary retention may also be observed at times, which may necessitate placement of a urinary catheter. Concern about any of these side effects is NOT a reason to avoid use of opioids, as pain management is of paramount importance and can be effective and safe using the guidelines as given.

Individuals differ in their response to opioid analgesics. If patients with serious illnesses treated for pain or dyspnea display opioid-induced side effects, such as oversedation, and experience good symptom control, then it might be reasonable to reduce the opioid dose. If, however, both poor analgesia and dose-limiting side effects occur, opioid rotation has been shown to be very effective to improve analgesia and dyspnea management and to lessen side effects.8,9 Differences between opioids in the balance between analgesic cross-tolerance level and the level of cross-tolerance to adverse effects can be exploited to clinical advantage. If opioids are being rotated because of decreasing effectiveness or limiting side effects (i.e., because of incomplete cross-tolerance), it is best to begin at around 50% of the equianalgesic dose and titrate to effect. However, the required decrease for incomplete cross-tolerance may be higher or lower, depending on the clinical context of the individual patient.10 For clinicians inexperienced in opioid rotation, we suggest reaching out, when possible, to available colleagues with pain and anesthesia training for guidance.

Adjuvant Medications and Interventions

Adjuvant medications are used mostly in combination with basic analgesics and opioids for specific pain types in order to maximize analgesia. They are sometimes used alone, but are often helpful as opioid-sparing agents, especially when there is a neuropathic component to the pain. Circumstances in which these medications may be particularly helpful include the following:

  1. 1. Neuropathic pain such as herpes zoster or peripheral nerve damage

  2. 2. Muscle spasm affecting abdominal organs (smooth muscle) or back pain (skeletal muscle)

  3. 3. Pressure cause by inflammation or tumors that affect organs and nerves, such as raised intracranial pressure, liver capsule stretch, or tumors pressing on nerves

Adjuvants include tricyclic antidepressants such as amitriptyline (or nortriptyline) and the anticonvulsant gabapentin (or pregabalin). Generally speaking, these agents tend to be useful when there are neuropathic components to the pain. These medication may take days to weeks to show effect and in combination are usually more effective than alone.

NMDA receptor antagonists may also play a role as adjuvant medications. Methadone, which acts both as an opioid and as an NMDA antagonist, may be especially useful because of the dual mechanism. Ketamine is an agent in this category that may be useful in the context of procedural pain or as an adjuvant medication when given in low (subanesthetic) doses.

Corticosteroids of any sort may be useful as adjuncts in the management of pain, in particular bony pain or headaches due to increased intracranial pressure. Corticosteroids, of course, have a number of common and well-known side effects, often limiting their longer-term use.

Integrative (Nonpharmacological) Treatment Modalities

Integrative modalities (sometimes referred to as complementary or alternative medicine) that have been described as effective in the management of pain include hypnosis, yoga, acupuncture, and massage. Active mind–body techniques, such as guided imagery, hypnosis, biofeedback, yoga, and distraction, all evoke pain modulation by engaging a number of mechanisms within the analgesic neuraxis.

Relaxation therapy might include progressive muscle relaxation to help patients recognize and lower body tension associated with pain and anxiety. Patients can be taught how to tense and relax different muscle groups in a relaxed and quiet setting, or to visualize a happy or peaceful scene and reduce body tensions. Breathing techniques such as patterned, shallow, or deep breathing can be used alongside relaxation approaches.

Hypnosis involves the cultivation of an altered state of awareness, leading to heightened suggestibility that allows for changes in perception and experience, bypassing conscious effort.11 In hypnosis the clinician enters the patient’s world, engaging the patient’s imagination as the agent of change and creating alternate experiences to promote therapeutic change. In trance, the patient addresses distressing symptoms utilizing suggestions by the clinician for altering sensations and perceptions and increasing comfort.12 Teaching hypnosis to patients, even to children and adolescents, is an extremely versatile skill, which can be acquired by clinicians through formalized training workshops and practice.13

Other cognitive and behavioral methods that may have a particular role in the care of children include comfort measures such as pacifiers, massage, touch, and music; distraction methods such as bubbles, counting, toys, and video games; and suggestion methods such as magic glove or magic blanket techniques.

Procedural Pain and Regional Anesthesia

Procedural anesthesia lies beyond the scope of this manual, though it should be remembered that any procedure, even one done in the context of palliative measures (e.g., pleurocentesis) should be accompanied by some sort of analgesia. Regional blocks may also play an important role in pain management, especially if the condition is likely terminal or in an acute trauma setting (e.g., pelvic or extremity tumor, severe extremity crush injury). Anesthesiologists and pain specialists accompanying a humanitarian aid mission may be unaware of the potential applications of their skills in the context of palliative care; providers should therefore make every effort to reach out to and integrate those specialists into the care of patients with palliative needs.

Care of the Dying Patient

Care of the dying patient is covered in detail in Chapter 9. Pain and symptom management is an important component of the care plan for dying patients. It should be remembered that opioids are the gold standard for management of pain and/or dyspnea, and that sedation may mask the symptoms (by inducing sleep or coma) but does not actually address the symptoms. Sedative agents such as benzodiazepines may well play a role in the management of patients with severe pain who are dying or otherwise, but these should not be confused with analgesic agents and proper pain management.

References

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