Paramedics play an important role in alleviating pain experienced by individuals in the community, with the relief of pain and distress described as a primary goal of paramedics and emergency medical services (EMS) (Callaham, 1997). In Australia, the Council of Ambulance Authorities (CAA) has identified quality of pain relief as a surrogate measure of compassion and caring, and has recommended that EMS develop and adopt clinical performance indicators that include reduction in pain (CAA, 2001).
Pain may be considered an innocuous diagnostic marker of injury or disease that will resolve once the underlying pathology is treated or the injury heals. However, there is increasing evidence that prolonged pain produces physiological changes that are associated with significant morbidity. It is known that acute pain may progress to chronic pain (Macintyre et al. 2010), and that chronic pain has psychosocial and economic consequences due to impaired mobility, loss of productivity and depression (McNeill et al. 2004; AIHW, 2010). It is estimated that pain is the third most costly health problem in Australia with an annual cost to the community estimated to be AUD$ 34 billion (MBF Foundation, 2007). This has led to a recommendation by the National Pain Strategy— representing health professionals, consumers and funding agencies—to recognize the management of pain as a national health priority (National Pain Summit, 2010).
Pain is a commonly encountered complaint in paramedic practice (McLean et al. 2002). However, the prevalence of chronic pain among patients cared for by paramedics has not been accurately defined. Paramedics may encounter patients with chronic pain when an exacerbation of pain is the chief complaint and the main reason for ambulance attendance. Chronic pain may also be a secondary finding that is revealed during the clinical examination.
Although paramedics are well prepared to manage acute pain, the assessment and management of chronic pain can provide many challenges, and as such this article aims to provide information to enable paramedics to more effectively care for patients living with chronic pain.
Definition of chronic pain
The International Association for the Study of Pain defines pain as ‘an unpleasant sensory and emotional experience, associated with actual or potential tissue damage, or described in terms of such damage’ (Merskey and Bogduk, 1994). This definition includes pain that has no obvious pathological basis; a feature of some chronic pain conditions. Chronic pain is pain that persists beyond its protective role as a signal of tissue injury and serves no useful purpose. Although definitions of chronicity very, chronic pain is generally defined as ‘pain experienced everyday for three months or more in the previous six months’ (National Pain Summit, 2010).
Prevalence of chronic pain
A study involving 15 European countries found the prevalence of moderate to severe chronic pain in adults to be 19% (Breivik et al, 2006). This is similar to the prevalence of chronic pain in the Australian community (Blyth et al, 2001).
Chronic pain is considered a significant health problem and a global health concern. The burden of chronic pain is more prevalent amongst females, and as pain may be a feature of degenerative disease associated with aging, older individuals are more susceptible to chronic pain (Blyth et al, 2001).
The economic burden of chronic pain is significant. However, the true cost must consider direct medical costs as well as individual costs that include interference with productivity, performance and quality of life (MBF Foundation, 2007). Chronic pain has a considerable impact on the community, and this burden is expected to increase as the population ages. Thus chronic pain is recognized as the ‘world's largest ‘undiscovered’ health priority’ (National Pain Summit, 2010).
Classification of chronic pain
Several approaches have been used to classify chronic pain. A broad classification involves the differentiation between cancer-related pain, and non-cancer pain associated with entities such as phantom limb pain and diseases such as osteoarthritis and fibromyalgia. Chronic pain has also been categorized as:
Physiology of pain
Pain is a subjective and complex phenomenon.The perception of pain begins with a process of nociception involving specialized pain fibres known as nociceptors that transfer information about noxious stimuli to the brain to enable perception of the location, type and intensity of the stimulus. This model may be expected to produce the same response to a standard stimulus. However, the perception and response to pain is mediated by psychological, social and environmental variables (Siddall and Cousins, 2004; Gatchel et al, 2007; Manchikanti et al, 2007). This means that the expression of pain may be influenced by prior pain experience, the individual meaning and consequence of the pain, the psychological and emotional state of the individual, and the social environment in which the pain is experienced. These factors have the potential to produce significant inter-personal differences in pain perception and expression, which may complicate the assessment of pain by health professionals, including paramedics.
Pathophysiology of chronic pain
The biopsychosocial model of chronic pain is a concept that takes into account the interaction of biological, psychological and social factors (Gatchel et al, 2007). Biologically, chronic pain is classified as nociceptive, neuropathic, or mixed (both nociceptive and neuropathic) in origin. Chronic pain may be due to ongoing tissue inflammation and injury and may continue as neuropathic pain after tissue healing has occurred due to abnormal processing of stimuli in peripheral and central nerve pathways, causing prolongation of pain.
In addition to biophysical factors, the emotional and social components of the pain experience can act to complicate the health problems experienced by those with disabling chronic pain.
The biological components of chronic pain
Nociceptive pain
Nociceptive pain involves the encoding and processing of noxious stimuli in response to the stimulation of nociceptors. When the skin, subcutaneous tissue, somatic or visceral structures are exposed to sufficient amounts of noxious mechanical, thermal or chemical stimuli, tissue damage occurs causing the release of chemical mediators associated with the inflammatory response (including prostaglandins, bradykinin, serotonin, substance P and histamine) that activate or sensitise nociceptors.
Acute nociceptive pain is normally short in duration and serves as the body's biological warning of harmful stimuli. However, nociceptive pain can become chronic, resulting in continuing pain even though the noxious stimuli may have been removed or attenuated (Pasero and McCaffery, 2011).
Activation of nociceptors triggers the propagation of an action potential conducted by the axons of afferent (sensory) nerves. The peripheral nerve pathways consist of two types of nociceptor fibres. Myelinated Aδ-nociceptive nerve fibres, which are primarily sensitive to mechanical or thermal stimuli, rapidly convey signals that are perceived as localised sharp pain. Unmyelinated slow conducting C-nociceptive nerve fibres respond to mechanical, thermal or chemical stimuli. These fibres are responsible for the transmission of poorly localized, dull and aching pain.
Afferent pathways synapse in the dorsal horn of the spinal cord. Pain signals are then projected via the medial and lateral spinothalamic tracts that terminate at higher central nervous system structures such as the brainstem, thalamus and cerebral cortex, where the signal is perceived and modulated (Pasero and McCaffery, 2011).
The transmission of pain impulses along ascending pathways can be inhibited or facilitated by the influence of descending tracts originating within the brainstem nuclei. Descending inhibition suppresses information processing via interneurones in the dorsal horn of the spinal cord. This modifies the transmission of noxious stimuli and produces analgesia through the release of endogenous opiates such as enkephalins and endorphins, or non-opiate inhibitory neurotransmitters such as serotonin (5-HT), norepinephrine (NE), and γ-aminobutyric acid (GABA). The resulting perception of pain is a complex process involving neuronal interrelationships between stimulation and inhibition.
Cancer-related nociceptive pain
There are three primary causes of cancer related nociceptive pain:
Neuropathic pain
Chronic neuropathic pain may be a consequence of tissue injury leading to dysfunction of peripheral or central nerve pathways. This can be caused by direct trauma, ischaemia, infection, metabolic derangement, or tumour invasion (Garcia and Altman, 1997). Injury to nerve pathways causes abnormal processing of afferent pain signals.
Dorsal horn neurones in the spinal cord become hyper-excitable and more susceptible to peripheral input, causing a stronger response to stimulation, a phenomenon known as hyperalgesia. Primary hyperalgesia is an increase in response to nociceptive input from inflamed or injured tissue region as a result of sensitisation of nociceptors by inflammatory mediators such as bradykinin, histamine, prostaglandins, thromboxane and leukotrienes.
Secondary hyperalgesia is an increased response to nociceptive input from areas that are adjacent to, or even remote to the primary site of injury. These changes are evident in symptoms of chronic pain, including hypersensitivity to stimuli associated with pain, and a pain response to stimuli that does not normally elicit pain. The latter is known as allodynia and can be seen where stimulus such as a light touch to skin causes pain (Siddall and Cousins, 2004).
The psychosocial consequences of chronic pain
Persistent pain can have significant psychological and social consequences. The perception of pain is influenced by the context in which it occurs, the individual's culture, their prior experiences of pain, their control over the pain, and the consequences of the pain (Manchikanti et al. 2002; Gatchel et al, 2007). Environmental conditions such as social economic status, unemployment and social support can also affect the individual's response to pain. These combined factors may result in disturbances of sleep, social interaction and social isolation, changes in mood such as irritability, helplessness, anxiety and depression (Manchikanti et al. 2002). The individual's emotional response to pain that can affect their ability to cope with pain, and therefore increase the physical complications of persistent pain.
The clinical assessment of patients with pain
The National Association of Emergency Medical Service Physicians (NAEMSP) recommends that prehospital pain management should involve a structured approach to the assessment and measurement of pain to guide pharmacological and non-pharmacological pain management interventions (Alonso-Serra and Wesley, 2003).
As pain is a subjective experience, a patient's self report is the most reliable indicator of the existence of pain and its intensity. The self report is dependant upon a patient's ability to communicate pain, which is affected by cognitive capacity and ability to perform abstract reasoning needed to quantify their pain. Paramedics should use validated tools that are reliable and practical for use in assessing pain in patients across the lifespan, and ensure that tools are available to measure pain in patients with cognitive impairment or where English is not their first language (Breivik et al, 2008; Lord, 2009).
Factors complicating the paramedic assessment of chronic pain
Paramedics trained to manage health emergencies may not consider chronic pain to be a health emergency and may not have the knowledge or skills required to assess and manage cases involving chronic pain. Although there is no direct evidence of paramedic's attitudes towards chronic pain in the paramedic practice setting, there is evidence that chronic pain is viewed as a low priority complaint in the emergency department (Wilsey et al, 2008).
Patients with chronic pain may have complex management plans. Treatment of chronic pain may involve a multidisciplinary approach that includes behavioural, psychological and pharmacological approaches to managing the pain. Paramedics may not see themselves as participants in this care process. Nevertheless, paramedics will be confronted with exacerbations of chronic pain and will need to make informed clinical judgements about the most appropriate means of relieving the individual's suffering.
Drugs used to manage chronic pain include anticonvulsants, antidepressants and neuroleptics (Feinberg, 2000). Paramedics may be unfamiliar with the role of these drugs in treating pain and lack knowledge of the possible interactions between the patient's medications and analgesics used by paramedics to treat pain.
Assessment of pain in the older person may be complicated by underlying health issues and comorbidities, polypharmacy, and altered metabolism of pain relieving medications (Dewar, 2006). Reluctance to report pain can occur due to cultural or religious beliefs, stoic attitudes, fears regarding ageing and concerns of side-effects of pharmacological treatment (Dewar, 2006; Herr and Mobily, 1991). The magnitude of these issues may be greater in patients suffering dementia or other forms of cognitive impairment and communication disorders. Recent studies have found that cognitive impairment due to dementia is associated with a reduced odds of analgesic administration compared with patients with similar pain-related pathology who were not cognitively impaired (Reynolds et al, 2008).
Paramedics must adapt their assessment of pain in those with cognitive impairment associated with disease such as dementia, and understand the needs of patients from cultural and linguistically diverse backgrounds and those who cannot adequately describe their pain experience due to disability.
‘Although paramedics are well prepared to manage acute pain, the assessment and management of chronic pain can provide many challenges’
Tools for the assessment of chronic pain
Assessment of a complaint of pain requires documentation of relevant medical history and a focussed clinical examination. Obtaining relevant medical history and information about the current complaint is a priority, as the information obtained can reveal important changes in the pain.
This assessment should include questions about the location, quality, intensity, sensory characteristics, duration, aggravating and relieving factors, and co-morbidities that may contribute to their painful condition. The intensity and severity of pain can be reliably assessed using a valid one dimensional tool such as the verbal numeric rating scale (VNRS) (Melzack and Katz, 2006).
However, chronic pain has several dimensions other than severity, and assessment requires the use of multidimensional tools in order to evaluate the physical, emotional and social effect of pain (Breivik et al, 2008). This presents a problem for paramedics where time constraints, limited medical history and lack of access to multidimensional pain scales may reduce the information available to form a clinical judgement.
The brief pain inventory (BPI) is a nine-item tool that has been used to assess a patient's pain severity and the degree of interference with daily functions over the past 24 hours (Pasero and McCaffery, 2011). This tool has been validated in several clinical settings involving chronic pain of varying origin. It is now one of the most common assessment tools for cancer related pain (Breivik et al, 2008). Other multidimensional pain assessment tools such as The McGill Pain Questionnaire (Melzack, 2005), which evaluates sensory, affective-emotional, evaluative and temporal aspects of a patient's chronic pain condition may be too complex and time consuming for routine use in the prehospital setting.
The clinical management of patients with exacerbation of cancer-related chronic pain
As pain associated with malignancies may present as a health crisis due to exacerbation of pain this section will focus on the paramedic management of cancer-related pain. Paramedics may encounter cases of episodic or breakthrough pain, which is defined as a ‘transitory exacerbation of pain experienced by the patient who has relatively stable and adequately controlled baseline (background) pain’ (Portenoy et al, 2004). Breakthrough pain may be associated with any form of chronic pain, and is a common, distinct and debilitating component of cancer-related chronic pain that occurs in a significant majority of cancer patients (Zeppetella et al. 2000).
The pain may occur due to exacerbation of the disease process, as a result of reduced therapeutic effect of an analgesic or have no identifiable cause. This is a complaint that paramedics may encounter when uncontrollable pain becomes a health emergency. Although chronic pain is not commonly described in clinical practice guidelines that inform paramedic practice, the guideline for paramedics in the UK states that breakthrough pain ‘may require large doses of analgesics to have significant effect’ (JRCALC, 2006).
Patients with chronic pain may have treatment plans that are individualised according to a variety of patient-related factors such as the type of pain, disease stage, current medication regime and patient preferences. Drugs used to treat breakthrough pain are commonly in the form of a short acting opioid such as fentanyl administered orally (Rauck, 2010), intranasally (Vissers et al, 2010) or via a transdermal patch (Mercadante, 2008).
The dose of opioid ‘rescue medication’ is recommended to be determined by individual titration as opposed to a fixed dose (Davies et al, 2009). This can pose difficulties for paramedics where clinical guidelines may constrain the type and dose of drugs used to treat pain. However, intravenous morphine is recommended for the treatment of breakthrough cancer pain (Davies et al, 2009; Mercadante, 2010) and as this drug is commonly used in paramedic practice its use may be indicated for the management of breakthrough pain.
In addition, intranasal fentanyl has been shown to be effective in the management of cancer-related breakthrough pain (Mercadante et al, 2009). As fentanyl delivered by the intranasal route is becoming more common in paramedic practice (Rickard et al, 2007) this may provide an additional means of managing breakthrough pain.
In order to provide effective care in this setting, the patient's management plan must be known and consultation with the patient's specialist or care team is recommended. However, this may not always be possible, and paramedics may have to make judgements about analgesic therapy on the basis of information provided by the patient and their carers.
It must be recognized that larger doses of opioids may be required in patients who have developed tolerance to these drugs. Tolerance is ‘a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug's effects over time’ (Heit, 2003).
Factors affecting chronic pain management in the prehospital setting
Long–term use of opioids may be associated with risk of opioid tolerance, drug dependence, addiction, diversion and polypharmacy. However, addiction resulting from long-term opioid use for chronic non-cancer pain is rare (Noble et al, 2010).
For chronic pain patients, especially those who regularly experience breakthrough pain or where there is no apparent basis for their pain, paramedics and other health professionals may perceive the individual as a ‘drug seeker.’ This stigma associated with chronic pain can result in poor pain management and inadequate patient care. However, it has been recognized that by inappropriately labelling patients as drug seekers, paramedics may withhold treatment where patients have very real pain requiring treatment.
Paramedics must understand that there are no reliable markers for pain other then the patient's self-report (Lord and Woollard, 2010). Patient behaviour in seeking analgesia for a legitimate complaint of pain may be misconstrued as addiction, whereas the behaviour may be one of pseudoaddiction: seeking analgesia due to poorly managed pain (Weaver and Schnoll, 2002).
The role of paramedics in patient education
Patients may be unfamiliar with the action and effective use of medications used to treat pain. In addition, they may delay taking their medication, wait too long before seeking relief and have difficulties describing and reporting their pain (De Wit et al, 1997). A lack of compliance with a pain management plan may reflect concerns regarding adverse side-effects, fears of addiction and dependence and inadequate knowledge of their condition.
Evidence shows that for patients with cancer-related pain, education can achieve a significant increase in the patient's knowledge of their condition and result in improvements in the management of their symptoms (de Wit et al, 1997).
Paramedics also have a role in educating the patient. For example, a patient with a recent prescription for transdermal buprenorphine (Norspan/Butrans) patch may be unaware that when the drug is administered by this route it can take up to three days to reach full therapeutic effect.
Paramedics have a role in advising patients about the basic principles of pain relief and interventions that paramedics can provide, suggest non-pharmacological interventions that may help to relieve pain and advise when it is appropriate to call for an ambulance. However, in order for paramedics to provide patient education, it is essential that paramedics themselves are educated in chronic pain management.
Recommendations for future management of chronic pain
The recent Australian National Pain Strategy has recognized six goals that are imperative to achieving the mission ‘to improve quality of life for people with pain and their families, and to minimize the burden of pain on individuals and the community’ (National Pain Summit, 2010).
These include: recognition of pain as a national health priority; knowledgeable, empowered and supported consumers; access to skilled professionals and best-practice evidence-based care; access to interdisciplinary care at all levels; quality improvement and evaluation; and future research.In order to achieve these goals, recommendations must be made regarding the management of chronic pain, and these can be targeted towards paramedics, patients and the community.
In order to provide a role in the management of pain in the community, paramedics must have the knowledge and skills needed to assess and manage chronic pain across a wide variety of populations, particularly cases that become a health emergency due to exacerbation of pain that cannot be controlled by the patient. A greater understanding of the multifactorial nature of pain can be achieved by integrating the study of pain management within undergraduate curriculum and the teaching of pain management through continuing professional education programs.
Targeted eduction may help reduce barriers to effective pain relief that are associated with attitudes and misconceptions regarding chronic pain and the potential for drug abuse among this vulnerable population. Education for paramedics should provide increased understanding of the biological, psychological and environmental factors affecting the perception and expression of pain and reinforce importance of the patient's self report of pain.
Paramedics must understand the role of pharmacological and non-pharmacological interventions and have the ability to educate patients and recognize the need to refer patients to pain specialists. In addition, evidence-based clinical practice guidelines must be developed to enable the management of chronic pain, particularly breakthrough pain, and provide therapeutic options for the management of chronic pain.
Finally, there is a need for further research that investigates the use of assessment tools suitable for a wide variety of populations, including those for the assessment of pain in individuals with cognitive impairment.
For patients, their carers and family members who are affected by chronic pain, it is vital that they understand how to effectively manage pain in community health settings and know how to seek help during a health crisis. Particular attention should be paid to those vulnerable to under treatment including the elderly, children, those with a history of drug abuse, and culturally and linguistically diverse groups.
Conclusion
Chronic pain is a complex and debilitating condition that can have a significant influence upon an individual's quality of life. In the community-based emergency health setting, paramedics play an important role in caring for patients who suffer from chronic pain. In order to function in this role, paramedics must have requisite knowledge of the pathophysiology and management of pain and be able to use evidence-based guidelines to assess and care for all patients with pain.