Emergency Pain Management

Introduction

Pain occurs in all clinical settings, but it is a particular problem in the emergency care settings; indeed, nearly every condition for which a patient presents to an accident and emergency (A&E) department in the United Kingdom (UK) involves some degree of pain. This chapter will describe the various types and classifications of pain, highlighting those which nurses in the emergency care setting are most likely to encounter. The chapter will then comprehensively explain how nurses should assess pain, and it will detail pain management interventions suitable for the emergency care setting (including pharmacological and non-pharmacological interventions). Finally, this chapter explores some of the ethical issues involved in pain management in the emergency care setting. In completing this chapter, you will be equipped with the skills and knowledge necessary to undertake the emergency assessment and management of a person's pain. 

What is pain?

Pain is a complex, multidimensional concept. It is, essentially, subjective - pain is whatever the person experiencing it says it is. It is also universally accepted as an unpleasant experience, and one that involves some degree of suffering. Pain is caused by a range of physiological problems - most often actual and / or potential tissue damage - and, though much less commonly, it may also be caused by psychological dysfunction. In this chapter, we will focus on pain caused by physiological problems, as these are the most frequent type of pain seen by nurses in emergency care settings.

The term nociception is used to describe the physiological processes which allow information about tissue damage to be communicated to the central nervous system (CNS), to be interpreted as 'pain'. There are four processes involved in nociception:

1. Transduction involves the conversion of a painful stimulus (mechanical, thermal or chemical) into an action potential. This is an electrical signal which is transmitted along pathways of nerves, from the peripheral nervous system (PNS) to the CNS. This process also involves a variety of other biological chemicals - including adenosine triphosphate (ATP), serotonin, histamine, bradykinin and prostaglandins.
2. Transmission involves the movement of the electrical 'pain' signal into the CNS. The pain signal is first transmitted to the spinal cord, and then to the dorsal horn (i.e. an area of the spinal cord which processes the pain signal to determine from where in the body it originated). From the dorsal horn, the pain signal is transmitted to the thalamus and the cortex in the brain.
3. Perception involves the brain recognising the pain signal as 'painful', and responding to it. This is a complex process; indeed, much is unknown about where and how the brain perceives pain, or how it determines conscious and unconscious responses.
4. Modulation is the final step in nociception; it determines how the brain perceives the 'pain' signal, and acts to inhibit these (and so relieve the experience of pain).

This is a complex process, so let's consider a case study example: 

Pain can be classified in a number of different ways. It is useful to think of pain as either: (1) nociceptive, or (2) neuropathic. Read the information in the following table:

	Nociceptive Pain	Neuropathic Pain
Definition	Normal processing of the noxious stimulus that has damaged, or has the potential to damage, the body's tissues, via the processes described above.	Abnormal processing of the noxious stimulus that has damaged, or has the potential to damage, the body's tissues; processing problems may occur in the PNS or the CNS.
Types	Somatic pain: From bone, joint, muscle, skin, connective tissue; described as 'aching' or 'throbbing'; usually localised. Visceral pain: From the organs (e.g. gastrointestinal tract or bladder); may be well-localised (e.g. where a tumour on an organ causes a well-defined ache) or poorly localised (e.g. where an obstruction to a hollow organ causes intermittent cramping).	Centrally-generated pain: This occurs when there is direct damage to the PNS or CNS, or due to dysregulation in the autonomic nervous system. Peripherally-generated pain: This occurs when pain is felt along a single nerve (e.g. a mononeuropathy such as trigeminal neuralgia), or along a series of nerves (e.g. a polyneuropathy, such as diabetic neuropathy or Glillain-Barre syndrome).
Management	Usually responsive to non-opioid medications (e.g. non-steroidal anti inflammatory medications [NSAIDS] and opioids).	May not be controlled by non-opioids or opioids; may require adjuvant therapies (e.g. antidepressants, anti-seizure drugs, ą2-adrenergic agonists, etc.).

In the emergency care setting, you will most often see nociceptive pain. However, occasionally a patient may present with neuropathic pain, particularly following a traumatic nerve injury or an illness involving inflammation or infection of the CNS (e.g. a herniated disk, multiple sclerosis, herpes zoster, neurotoxins, etc.). It is important to remember that neuropathic pain requires long-term management strategies beyond those administered in the emergency care setting.

In addition to nociceptive versus neuropathic, pain may also be classified as either: (1) acute, or (2) chronic. Read the information in the following table:

	Acute Pain	Chronic Pain
Onset and Duration	Pain which has a sudden onset, but which lasts only as long as it takes the tissue injury to heal.	Pain which may have a gradual or sudden onset, but which lasts longer than it takes for the tissue injury to heal, or well past the normal time for recovery.
Severity	May be mild, moderate or severe.	May be mild, moderate or severe.
Cause	Generally, a clearly-defined cause, such as an injury or illness. For example: labour, trauma (e.g. fracture, laceration), infection (e.g. cystitis), angina, etc.	May not be known, or the cause may be different than the cause of the original tissue injury. For example: cancer pain, non-cancer pain (e.g. fibromyalgia), etc.
Course	Pain gradually resolves as the tissue injury heals.	Pain may not resolve; there are characteristic periods of worsening and improving.
Manifestations	Sympathetic nervous system activation (e.g. increased heartrate, increased respiratory rate, increased blood pressure, diaphoresis, pallour, anxiety, agitation, urine retention).	Behavioural manifestations (e.g. flat effect, decreased physical movement / activity, fatigue, withdrawal, etc.).
Treatment	Treatment involves: (1) analgesics for the control of pain, and (2) treatment of the underlying cause of the pain.	Treatment involves long-term analgesia in combination with a variety of psychosocial interventions.
Goals of Treatment	Pain control and eventual elimination.	Pain control to the greatest extent possible; enhance function and quality of life.

In the emergency care setting, you will most often see acute pain. However, occasionally a patient may present with chronic pain, usually the exacerbation of chronic pain and / or the condition which causes it (if known). As with neuropathic pain, it is important to remember that chronic pain requires long-term management strategies beyond those administered in the emergency care setting.

Pain assessment

You studied the fundamentals of rapid pain assessment in an earlier chapter of this module. Remember: rapid pain assessment is completed using the 'OPQRST' mnemonic:

O	Onset: "When did the pain begin?"
P	Provocation and palliation: "What makes the pain worse? What helps the pain?"
Q	Quality: "Describe the pain." (E.g. sharp, dull, stabbing, etc.).
R	Region and radiation: "Where do you feel the pain? Does the pain spread to other areas of your body?"
S	Severity: "On a scale of 1 to 10, where 1 is no pain and 10 is the most severe pain you have experienced, how would you rate the pain?" (Note that there are a range of other pain scales - including visual scales for paediatric and non-verbal patients - which may be used in emergency settings).
T	Time: "How long has the pain been present?"

This section will cover pain assessment in greater depth. In reading this section, it is essential to remember that hospitals may have their own pain assessment policies and procedures; it is important that nurses work within these at all times to ensure their practice is compliant. However, all pain assessments general involve an assessment of the characteristics of pain. This may include asking the patient about:

• The location in which the pain occurs. It is important to note that a patient may not be able to specify where the pain occurs (i.e. they may state that they 'hurt all over'), and even if a location is identified this may not be the site at which the pain originates (e.g. due to referral of the pain along nerve pathways).
• The pattern of the pain (e.g. its onset and duration, changes over time, etc.).
• The severity of the pain. This is often measured using a pain scale - for example, a numeric scale (0 = no pain, 10 = severe pain) or verbal descriptor scales (e.g. 'none', 'mild', 'moderate', 'severe', etc.).
• The quality of the pain - that is, how the patient describes the nature of the pain. Neuropathic pain is often described as 'burning', 'shooting', 'stabbing', 'numbing' or 'itching'. Nociceptive pain is often described as 'aching', 'throbbing' or 'cramping'.
• Any associated symptoms. Pain is often associated with symptoms such as fatigue, nausea and anxiety, and these symptoms may exacerbate (or be exacerbated by) the pain. The nurse should also ask about the situations which provoke or palliate the pain (i.e. make it worse and better).
• Strategies which the patient has used to manage the pain, and if these are effective.

Consider the following case study example:

As illustrated by this case study, pain assessment focuses on speaking with a patient to determine their experience of pain. However, it is important to highlight that many patients in an emergency care setting are non-verbal - for example, they are unconscious, heavily sedated or neurologically impaired, etc. In such case, there are a variety of observational tools which can be used to identify the objective signs of pain, often via measurement of the patient's vital signs in a primary and secondary survey.

Untreated pain can have a variety of negative impacts upon a patient. It may cause dysregulation in a patient's:

• Endocrine / metabolic function (e.g. increasing the release of some hormones, etc.).
• Cardiac function (e.g. increasing heart rate and myocardial oxygen consumption, etc.).
• Respiratory system, (e.g. decreasing tidal volume, causing hypoxaemia, etc.).
• Genitourinary function (e.g. decreasing urinary output, causing urinary retention, etc.).
• Gastrointestinal function (e.g. reducing bowel motility, etc.).
• Musculoskeletal function (e.g. causing muscle spasm, impairing motility, etc.).
• Neurologic function (e.g. impairing cognition, etc.).
• Immunologic function (e.g. decreasing the immune response, etc.).

Non-verbal patients may also demonstrate their experience of pain in a variety of other ways - for example:

• Vocalisations (e.g. moans, grunts, crying, etc.).
• Facial expressions (e.g. grimacing, wincing, clenched teeth, etc.).
• Noisy and / or laboured breathing.
• Restlessness, rocking, writhing, clenched fists, rigidity, etc.

It is also important to make a note about the assessment of pain in children. Pain is a complex concept, and even older children may be unable to explain if, where and how they experience pain. There are a number of physical signs that indicate a child may be experiencing pain (or is otherwise distressed) - for example, a child who cries with:

• A mouth which is open and squarish in shape.
• Brows which are lowered and drawn together, creasing the forehead.
• Broadening and bulging of the nose.
• Raising of the tissue on the upper cheeks.
• Eyes which are squeezed tightly closed.

It is essential that nurses working in emergency care settings seek information from the parent/s or caregiver/s of a child whom they are assessing for pain; it is, after all, these people who know the child best, and who can best identify what is 'normal' and what is not.

Nurses must also be able to assess pain in older adults. Like children, older adults (and, specifically, those with cognitive, sensory-perceptual and motor impairments) may be unable to express their experience of pain. Furthermore, older adults may consider pain to be a normal, inevitable part of ageing, and may therefore fail to report pain to nurses for fear they will be a 'burden'. For older adults, the same pain assessment as with adults (described above) is used; however, there is a particular need for assessment to be conducted in an unhurried, supportive manner. Nurses must also be aware that older patients may use a range of terminology to describe their pain - for example, 'aching', 'soreness' or 'discomfort' - and nurses should mimic this language. 

Pain management

Once pain has been assessed, as described in the previous section of this chapter, interventions to manage the pain can be implemented. Again, it is essential to remember that hospitals may have their own policies and procedures for pain management (and particularly related to the use of pharmacological interventions); it is important that nurses work within these at all times to ensure their practice is compliant. However, all pain management follows these same general best-practice principles:

• Nurses must remember that pain is a subjective experience - this means the patient is the best judge of their own pain experience, and must be listened to and believed.
• Every patient deserves, and has a right to receive, adequate pain management. This includes those whose pain is self-inflicted, and those with substance abuse issues.
• Both pharmacological (i.e. drug) and non-pharmacological (i.e. non-drug) strategies should be used in combination to achieve the best possible pain relief for the client.
• The side-effects of pharmacological pain relief must be prevented and / or managed. This can be done by changing the dosing regimen to maintain constant plasma levels of the drug, changing to a different medication in the same class if the patient exhibits sensitivities, adding a new drug to counteract the adverse effects of another (e.g. for opioid-induced constipation, a stool softener or stimulant laxative is often prescribed), or using an administration route that limits concentration of the drug.
• The need for ongoing pain management beyond that administered in the emergency care setting should be considered.
• Patient teaching (where appropriate), and the ongoing assessment of the patient's pain, are fundamental aspects of pain management in the emergency care setting.

The interventions selected to manage the pain will be decided based on a variety of factors, including: (1) the type of pain experienced (e.g. nociceptive vs. neuropathic, acute vs. chronic), (2) the severity of the pain, (3) the location and pattern of the pain, (4) any associated symptoms and underlying medical conditions, and (5) the patient's preference. Options for pain management in the emergency care setting are described following:

• Pharmacologic therapy, or drug therapies. These are generally divided into three categories: (1) non-opioid analgesics, (2) opioid analgesics, and (3) co-analgesics or adjuvant medications. Mild pain is usually relieved using non-opioid analgesics, however moderate to severe pain usually requires an opioid (alone or in combination with a non-opioid). Some types of pain, including neuropathic pain, also require a co-analgesic or adjuvant medication. Let's look at these medications in greater detail:
• Non-opioid analgesics: these include salicylates (e.g. aspirin), acetaminophen, non-steroidal anti-inflammatory medications (NSAIDS - such as ibuprofen and diclofenac), and cyclo-oxygenase-2 (COX-2) inhibitors (e.g. celecoxib). These medications are useful for mild to moderate pain, are typically administered orally, and do not produce tolerance or physical dependence. However, they do have an analgesic ceiling (i.e. a limit to their analgesic properties), and gastrointestinal upset (including, in longer-term administration, bleeding and liver toxicity) is a known side-effect.
• Opioid analgesics: these include μ-agonists (e.g. morphine, fentanul, oxycodone, hydrocodone, codeine, etc.), mixed aconist-antagonists (e.g. butorphanol), and partial agonists (e.g. buprenorphine). These medications are typically used for moderate to severe pain. They have a number of known side-effects, including constipation, nausea and vomiting, pruritus and, in severe cases, sedation and respiratory depression. Constipation is one of the most common side-effects, therefore opioids are routinely administered with a stimulant laxative and stool softener. Anti-emetics such as metoclopramide may be administered to prevent or relieve nausea and vomiting, while antihistamines may be administered to prevent or relieve pruritus. 
• Co-analgesics or adjuvant medications: there are a variety of co-analgesics or adjuvant medications which may be used in combination with non-opioid and / or opioid analgesics to achieve pain relief. These agents were generally developed for purposes other than pain relief, and subsequently found to be effective for pain. Common co-analgesics or adjuvant medications include:
• Tricyclic antidepressants, which act to increase the levels of serotonin and norepinephrine (which are natural pain relievers) in the CNS. Doses of antidepressants required for pain relief are often significantly lower than those used to treat depression.
• Anti-seizure medications, which are particularly effective for neuropathic pain, and may be used prophylactically for migraines.
• ą₂-adrenergic agonists, such as clonidine. These are often prescribed for chronic and neuropathic pain, and are not often seen in the emergency care setting.
• Corticosteroids, such as dexamethasone and methylprednisolone. These are particularly useful for cancer pain (acute or chronic), pain due to spinal cord compression, and inflammatory joint pain. Particularly when given in high doses, corticosteroids have many side-effects - including hyperglycaemia, fluid retention, gastrointestinal bleeding, muscle wasting, osteoporosis and adrenal suppression
• Local anaesthetics - these may be used for acute pain and chronic neuropathic pain. As locally-administered medications, systemic side-effects are rare, however, dysrhythmia has been observed.
• GABA agonists, such as baclofen, which is used for muscle spasm.
• NMDA antagonists, such as ketamine, which is used for peripheral neuropathic pain. These are rarely seen in the emergency care setting.
• Mixed μ-agonists opioids and NE/5-HT reuptake inhibitors, such as tramadol, which are used for a variety of nociceptive and neuropathic pain. They have side effects similar to those produced by opioids.

It is important to note that pharmacological analgesics in the emergency care setting may be administered via a number of different routes, including orally (if the gastrointestinal system is functioning normally), parenterally (i.e. intramuscularly or intravenously) sublingually or buccally (for rapid absorption into the systemic circulation), intranasally (for rapid absorption through the mucosa), rectally, transdermally and / or intraspinally. It is important to remember that not all medications are suitable for administration via all routes; it is essential that nurses refer to drug administration manuals, and follow the policies and procedures in use in the clinical setting where they work.

• Non-pharmacologic therapies - interventional therapies. These include:
• Therapeutic nerve blocks, which involve the administration of a local anaesthetic to achieve regional anaesthesia. For severe chronic pain, neuroablative techniques may be used; this involves techniques to irreversibly destroy nerve cells and, so, prevent the transmission of pain signals.
• Neuroaugmentation, which involves the electrical stimulation of the CNS to disrupt the transmission of pain signals.
• Non-pharmacologic therapies - non-drug therapies. These include a range of pain-relieving interventions such as massage, transcutaneous electrical nerve stimulation (TENS), acupuncture, heat therapy and cold therapy. Cognitive therapies, such as distraction, hypnosis and relaxation strategies, may also be used. The evidence for the effectiveness of these strategies in relieving pain, particularly in acute settings such as emergency care settings, is variable; however, if a patient wishes to use these strategies because they believe they help to relieve their pain, they should be supported to do so.

It is important to note that there are a variety of barriers to effective pain management in the emergency care setting. These barriers include fear of tolerance / addiction (described in greater detail in a later section of this chapter), concern about side-effects, a desire to be stoic and ineffective medication dosing regimens, etc. If nurses are aware of these barriers, they can respond effectively to them to ensure each patient is given the best pain relief possible.

Ethical issues in pain management

There are two key ethical issues associated with pain management with which nurses in emergency care settings must be familiar:

• Fear of tolerance / addiction. It is common for patients and their families / carers to believe that the use of opioid analgesics in particular leads to rapid tolerance and / or addiction - both of which are unwanted outcomes. Patients and their families / carers must be assured that, in the short term, the doses of opioid analgesics provided in the emergency care setting are highly unlikely to result in tolerance or addiction, and that any side-effects which are experienced because of the use of these medications can be effectively managed using the strategies described earlier in this chapter.
• Fear of hastening death by administering analgesics. It is common for patients and their families / carers to believe that analgesics, and particularly opioid analgesics, may only be given to patients who are terminally ill, and that these medications may hasten their death. Patients and their families / carers must be assured that analgesics, including opioid medications, are a crucial aspect of pain management, and are used with the aim of providing pain relief and for no other purpose.

In emergency care settings, nurses will often care for patients with current or previous substance abuse problems. Often, this abuse will involve opioid analgesics - and this may complicate the emergency management of pain for the patient using prescription opioids. However, with careful planning and administration, opioids can be used for pain relief effectively and safely in patients with substance abuse problems. It is important that an interdisciplinary team is involved in the assessment and implementation of pain management interventions for patients with substance abuse problems. You studied substance intoxication in the emergency care setting in an earlier chapter of this module; you should revise this chapter now, if required.

Conclusion

Pain occurs in all clinical settings, but it is a particular problem in the emergency care setting; indeed, nearly every condition for which a patient presents to an A&E Department in the UK involves some degree of pain. This chapter has described the various types and classifications of pain, highlighting those which nurses in the emergency care setting are most likely to encounter. The chapter then comprehensively explained how nurses should assess pain, and it detailed the pain management interventions suitable for the emergency care setting (including pharmacological and non-pharmacological interventions). Finally, this chapter explored some of the ethical issues involved in pain management in the emergency care setting. In completing this chapter, you are equipped with the skills and knowledge necessary to effectively assess and manage a person's pain in the emergency care setting. 

Reference list

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Howard, P.K. & Steinmann, R.A. (Eds.). (2010). Sheehy's Emergency Nursing: Principles and Practice. Naperville, IL: Mosby Elsevier.

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Royal College of Nursing. (2009). The Recognition and Assessment of Acute Pain in Children. Retrieved from: https://www2.rcn.org.uk/__data/assets/pdf_file/0004/269185/003542.pdf

Royal College of Nursing. (2015). RCN Pain Knowledge and Skills Framework for the Nursing Team. Retrieved from: https://www.britishpainsociety.org/static/uploads/resources/files/RCN_KSF_2015.pdf

Samcam, I. & Papa, L. (2016). Acute Pain Management in the Emergency Department. Intech Open (open access). Retrieved from: http://www.intechopen.com/books/pain-management/acute-pain-management-in-the-emergency-department

Thomas, S.H. (2013). Management of pain in the emergency department. International Scholarly Research Notices (open access). Retrieved from: https://www.hindawi.com/journals/isrn/2013/583132/