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Top 10 Things to Know About Acute Pain Management

Bill Lord BHlthSc, GDipCBL, MEd, PhD

Pain Assessment

Introduction

Relief from pain is a basic human right. All healthcare professionals have an obligation to provide the level of care that would be offered by a competent and careful healthcare professional in their field of practice while acting within their scope of practice. This includes care that aims to alleviate pain.1 Despite a growing body of knowledge in the field of pain physiology and pain management, there is still evidence of inadequate management of acute pain in emergency medicine.2-4 In the field of EMS, evidence indicates a failure to properly assess and treat pain.5-9

This article therefore aims to address some of these barriers by providing better information to improve and maintain the quality of care provided by paramedics to patients in pain.  

 

1. Pain management barriers

Pain is an important biological and protective response to tissue damage. Although pain may be viewed from that purely neurological perspective, it is also a complex phenomenon, with the perception and expression of pain mediated by complex social, environmental and psychological factors.11

One recent article describing the results of an analysis of paramedic interviews found: 1) reluctance to administer opioids to patients in the absence of objective signs such as deformity; 2) preoccupation with potential malingering; 3) ambivalence about the degree of pain control to target or to expect; 4) fear of masking diagnostic symptoms; and 5) aversion of aggressive dosing of opioids.10 The authors identified attitudinal barriers to appropriate pain management that may be amenable to modification.

Healthcare providers are likely to experience significant inter-personal variations in the way people respond to pain, and paramedics tend to use patient behavior as a means of validating the patient’s report of pain severity.12 This may lead to disparities in the quality of care if the patient’s pain-related behavior does not meet the paramedic’s expected norm. The most useful definition of pain was formulated by a respected pain researcher: “Pain is what the person says it is and exists whenever he or she says it does."13

 

2. Assessment of pain

Understanding of the patient’s complaint of pain requires the paramedic to conduct a focused assessment and clinical examination of the patient to form a clinical impression and to reach a decision regarding the most appropriate means of managing this symptom. Read “The Assessment of Pain in Paramedic Practice” for details on mnemonics and scales used to assess and measure pain the field. The information obtained from the patient must include previous medical history, medications and allergies.

A validated pain scale should be used to allow the patient to rate the severity of their pain. Evidence has found that health professionals tend to underestimate pain.15 It also appears that as clinical experience increases, so too does the underestimation of pain.16

Avoid estimating pain severity based on patient behavior or other non-verbal cues. In addition, avoid using vital signs to confirm the presence of severe pain, because pulse, blood pressure and respiratory rate are not reliably correlated with pain severity.17,18 The most reliable measure of the quality and severity of pain is the patient’s description.

 

3. Believing the patient

Research by Walsh and colleagues found that paramedics were preoccupied with potential malingering among patients reporting pain.10 Paramedics have also reported that they use patient behavior to decide whether to believe the patient’s report of pain.12 This may be associated with concerns that some patients reporting are seeking opioids for non-therapeutic reasons. Because patient history is often inadequate to make this determination in the field, it is difficult to discriminate between behavior associated with opioid addiction and behavior associated with pain. In fact, patients may ask for analgesics by name when they know which drugs are most effective in relieving their pain. If patients are seeking analgesics for unrelieved pain, they may be physically dependent on analgesics to relieve their pain. This is known as pseudoaddiction, and is not evidence of addiction.19

Paramedics who, when working within their scope of practice, withhold analgesia without objective and validated evidence of addiction or contraindication of analgesia, may place the patient at risk of inadequate care. Before withholding analgesia, take a moment to consciously evaluate the quality of the clinical decision, and ensure that the potential for bias has been controlled to reduce the risk of error.

 

4. The right drug

Paramedics may be able to implement pharmacological or non-pharmacological approaches to alleviating the patient’s pain. The management of pain will usually be informed by clinical practice guidelines or treatment protocols for different scopes of practice that typically list several drugs that are indicated for the alleviation of pain. The choice of drug is based on pain severity, available routes of administration, and patient history that may reveal contraindications to particular therapies. Paramedics should remember that although there are contraindications to specific analgesics, there is no contraindication to analgesia.

Pain may be alleviated by inhibiting prostaglandin synthesis, which is associated with the stimulation of nociceptors or specialized neurons that transmit the sensation of pain. This is the action of drugs such as aspirin, ibuprofen, ketorolac and other non-steroidal anti-inflammatories.21

Where nerve-blocking medications are allowed in the prehospital environment, pain may also be relieved by blocking transmission of pain messages by binding to opioid receptors in the central nervous system (morphine and other opioids); or by blocking the transmission of action potentials of afferent neurons using a drug such as lidocaine to achieve a nerve block. A nerve block may be a good option in cases of isolated extremity trauma such as a femoral fracture, and the use of a fascia iliaca block to achieve analgesia. In these cases has been found to be practical and effective in the prehospital setting.20-22

Patients with mild pain may benefit from acetaminophen or non-steroidal anti-inflammatories. Opioids, such as morphine, are typically indicated for severe pain.23 Unlike morphine, the synthetic opioid fentanyl is highly lipid soluble, making it suitable for transdermal and intranasal administration. Although transdermal therapy is uncommon in EMS, intranasal administration of fentanyl has been shown to be highly effective in treating pain in children in the prehospital setting, and in pediatric trauma in the emergency department (ED) setting.24,25 Fentanyl is also effective given intravenously, producing analgesia that is comparable to equivalent doses of morphine, with a low frequency of adverse effects, the most common being nausea.26,27

One drug that is gaining popularity as an analgesic in the prehospital setting is ketamine. This drug is classed as an NMDA receptor antagonist but also has additional actions that are not yet fully understood.28 The drug has been found to be a safe and effective analgesic in prehospital care when given in subanesthetic doses.29 It may have particular benefits in the severely injured patient because it reduces the risk of hypotension and respiratory depression in the unstable trauma patient.30

 

5. The right dose

Morphine has been described as the gold standard against which other analgesics are compared.31 The therapeutic total dose of morphine for patients alike frequently listed as 0.1 mg/kg intravenously for patients with severe acute pain. This amount is for pediatric patients as well as adult patients. However, this dose has been shown to be ineffective for controlling severe pain in the majority of patients.32 A starting dose of 0.1 mg/kg intravenously, and further doses at 0.05 mg/kg titrated to achieve a level of pain relief that the patient determines appropriate has been found to be safe and effective when used in the prehospital setting.33

The way to determine whether further doses of opioid are required to relieve pain is to ask the patient. There is significant inter-patient variability in response to morphine administration and the dose required to achieve analgesia. Some patients experiencing severe pain may require analgesic doses that exceed clinical guidelines. This may be particularly evident in patients with opioid tolerance. Where possible, consult for advice if significant pain remains following administration of the maximum dose allowed by the guideline or protocol.

Unlike some other analgesics, morphine and fentanyl do not have a therapeutic ceiling, and the dose can be increased until analgesia is obtained or until adverse effects are noted.34

 

6. Adverse effects

Analgesic administration is associated with adverse effects. For the opioids, the most feared is respiratory depression. Opioids produce a dose-dependent respiratory depression through a combination of mechanisms that include a reduction of the ventilatory response to carbon dioxide.35 However, the actual rate of respiratory depression associated with opioid administration in the prehospital setting is unknown. In the postoperative setting, rates of respiratory depression of 1% and a 5% rate of hypotension have been reported.36 Age is associated with an increased risk of respiratory depression, with patients aged greater than 70 years having 5.4 times the risk than younger patients.37 Respiratory rate is a poor indicator of respiratory depression, with level of sedation a better early indicator of respiratory depression.38 Paramedics should routinely use a sedation scale to identify potential for respiratory depression. The following is recommended:39

Table 1: Sedation Score

Score Sedation Level
0 Wide awake
1 Easy to rouse
2 Constantly drowsy, easy to rouse but unable to stay awake (e.g. falls asleep during conversation); early respiratory depression
3 Severe; somnolent, difficult to rouse; severe respiratory depression

Patients with a score of greater than 1 are at risk of respiratory depression.

Opioid allergy may be cited by patients who refuse analgesia. However, the true rate of IgE mediated allergy to morphine is low.40 When a patient describes an allergy, they may be referring to a drug side effect, such as nausea or pruritus (itching), which may associated with localized urticaria at the injection site and along the vein proximal to the site. This usually resolves without treatment but may require switching to an analgesic such as fentanyl which is unlikely to produce histamine release.41 Mild side effects, such as nausea, may not preclude the administration of the medication.

 

7. Special populations

Patients at either end of the age spectrum are at risk of inadequate analgesia. Older patients in the emergency department (ED) setting are less likely to receive analgesia, and this disparity has also been documented in young children.42,43 Children treated by paramedics are less likely to receive analgesia than older patients, and this may be associated with difficulties in assessing pain in children.44 Communication difficulties may be associated with aging, and the assessment of pain in pre-verbal children may be challenging. Pain scales are available for these vulnerable populations, and these are described in the EMS Reference article, “The Assessment of Pain in Paramedic Practice.”

Gender and ethnicity are associated with disparities in the care of patients with abdominal pain, with females and non-Caucasians less likely to receive analgesia.45 In EMS, female patients are less likely to receive opioids for pain after controlling for age, pain severity and type of pain.46,47

Racial and ethnic disparities exist in the care of patients with pain.48 It is important to consider the potential influence of personal attitudes on the assessment of pain, such as social or racial stereotyping may subconsciously affect the paramedic’s interpretation of pain-related behavior.

Patients receiving opioid agonist therapy (OAT), such as buprenorphine or methadone, to treat opioid addiction may pose special challenges. Patients on OAT will invariable suffer illness or injury associated with pain. Several misconceptions may reduce the odds of effective pain management in these situations. These include:

“1) The maintenance opioid agonist (methadone or buprenorphine) provides analgesia; 2) use of opioids for analgesia may result in addiction relapse; 3) the additive effects of opioid analgesics and OAT may cause respiratory and central nervous system (CNS) depression; and 4) the pain complaint may be a manipulation to obtain opioid medications, or drug-seeking, because of opioid addiction.”49 All these assumptions are incorrect. Pain assessment may also be complicated by the finding that patients with long-term opioid use often suffer opioid-induced hyperalgesia (OIH).50 This means that these patients may exhibit a lower threshold to painful stimulus and have a reduced tolerance to pain.

 

8. Non-pharmacological therapy

Distraction techniques have been shown to be effective in reducing pain in children, but are infrequently documented in EMS.51,52 Distraction can involve shifting patient’s focus from their pain to another activity or interest In children this may be achieved by engaging the child in a discussion of their favorite toys or movie characters.

Splinting is commonly described as a form of analgesia because it helps exacerbate pain due to movement. However, this gives the impression that pharmacological analgesia can be omitted when a splint is used to immobilize a fracture. Analgesia should be considered prior to splinting.

Cold water reduces the pain associated with burns. However, cooling should cease after 20 minutes as there is a risk of hypothermia in patients with large surface area burns, particularly in children.53-55 Ongoing analgesia will usually be required, and this usually requires a strong opioid, such as morphine or fentanyl.

 

9. Alternative therapies

The future holds the promise of other therapies for the management of pain in the prehospital setting, particularly in the treatment of persistent pain in the community. Research has demonstrated the effectiveness of transcutaneous electrical nerve stimulation (TENS) for relieving acute pain in the prehospital setting.56 Paramedics have also successfully used acupressure to relieve pain.57,58

 

10. Evaluation of response to therapy

A pain severity score does not identify a patient’s desire for analgesia.59 Rather, the pain score serves as a means of establishing a baseline for severity to compare trends and to evaluate the efficacy of interventions that aim to alleviate pain. Pain scoring should routinely be performed prior to and following interventions to manage pain. EMS organizations are encouraged to develop clinical performance standards for pain management. This may include benchmarks for reduction of pain severity and surveys of patient satisfaction. One study has used a final pain score of 3 out of 10 or less as the performance benchmark in patients with severe acute pain in the prehospital setting.58

 

Conclusion

Pain management is an important component of paramedic practice. However, unreasonable fears about the safety of opioids may compromise the quality of care. In addition, paramedic beliefs about the patient’s motives for reporting pain may prejudice the clinical impression and lead to the withholding of analgesia despite the difficulties in disproving the patient’s report. Ongoing education, clinical audit based on evidence-based practice, and clinical advocates for high quality care will help to improve practice.

 

References

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Published: June 30, 2015
Revised: February 6, 2016