An introduction to the biopsychosocial complexities of managing wound pain
Cliff Richardson. PhD.
Lecturer, School of Nursing, Midwifery and Social Work, University of Manchester. UK.
Correspondence address
Cliff Richardson
School of Nursing Midwifery and Social Work
Jean McFarlane Building
Oxford Road
Manchester
M13 9PL
Tel 0161 306 7639
Fax 0161 306 7707
Declaration of interest
Cliff Richardson has received an unrestricted grant from Molnlycke Healthcare
Introduction
Wounds can be painful and managing this pain, especially at key points in time, such as dressing changes is one of the most challenging aspects of care for practitioners looking after people with wounds 1 2. Much has been written about wound classification and the specific differences between acute and chronic wounds but less has been described about the potential differences that these classifications may have on the pain experiences of individuals. Applying similar pain skills to patients with an acute wound healing through primary intention and a chronic oozing wound will not be effective and could negatively affect the healing process 3. Further complications occur when chronic wounds with associated chronic pain require dressing changes. At this time the chronic pain is compounded by the presence of acute/procedural pain caused by disruptions of the wound environment and irritations such as shearing forces and touch 4. This paper will explore the variations in pain that can be seen between acute and chronic wounds as illustrated by some of the important aspects of pain and will propose that wound care practitioners require a wide range of skills to manage these pains.
Pain
Pain has been classified in various ways. The simplest classification is into acute pain and chronic pain where acute pain is pain of recent onset and is projected to last less than 3 months 5. Chronic pain is pain that has lasted continuously or intermittently for at least three months 6. Using time as the only criterion however can be problematic as the point chosen for conversion between the pain types is arbitrary hence separate classifications have arisen. Examples of other taxonomies are that chronic pain should be defined as ‘pain that extends beyond the expected period of healing’ and where pain is defined in terms of time and pathology7. For ease of description within this paper, pain will be referred to here as acute and chronic.
It is universally agreed that pain is a biopsychosocial phenomenon which means that the experience (for the person with pain) and the assessment of pain (by an observer) are influenced by biological/physical, social, psychological, cultural, environmental, spiritual, and many other factors 8 9. As a consequence it makes all aspects of pain related care extremely complicated. Before moving onto the specifics for wound care it is important to explore some of these complexities.
Biological/physical
Nociception is the normal protective physiological detection of pain 10 and occurs following trauma or injury. Nociceptive pain may however induce considerable changes within the nervous system. These changes occur at the periphery, spinal cord and within the brain. This neuroplasticity can have repercussions in how pain is felt as it can provoke conditions where pain is physiologically modified. Perhaps the most reported and important of these conditions in terms of pain are allodynia and hyperalgesia. Allodynia is a condition where normally painless stimuli such as touch are felt as pain 11. Hyperalgesia is an exaggerated pain response to a normally painful stimulus 11 and is a normal consequence to injury but abnormal if it persists after healing has occurred.
Social/cultural
Pain has a significant social element which makes the context of the pain very important. Beecher’s work in the 1940’s identified that soldiers with injuries encountered on the battlefield tended to exhibit different behaviours than people with similar injuries but in a domestic type situation 12. The pivotal work of Zborowski (1950’s) in the USA found that pain behaviours varied considerably between ethnic groups 13. In his work the ethnic Irish group was generally stoic and did not show their pain whereas the ethnic Italian’s tended to outwardly show their pain. Although it has been shown that in modern multicultural societies cultural differences reduces over time it remains clear that reaction to pain will vary between cultures and that cultural concordance between pain sufferer (patient) and pain observer (HCP) is important14 15.
Psychological
Various psychological factors are known to influence pain reaction and sensitivity. In chronic pain conditions these contribute to the disabling effects 16. It is impossible to cover all of the psychological aspects that influence pain here, so to best illustrate these points key pain related factors of catastrophising and stoicism have been chosen. Broadly speaking catastrophizing is the tendency to magnify the threat of pain 17. High catastrophizers are known to exhibit magnified behavioural responses to pain and exaggerate pain intensity 18 19. The opposite extreme is stoicism. Stoics are likely to hide pain and underplay their pain. Other recognised psychological features that influence the perception of and reaction to pain are anxiety, depression, coping style and locus of control8 20. Simple measurement tools such as the Pain Catastrophising Scale (PCS)17 and Hospital Anxiety and Depression Scale (HADS)21 are available to capture the psychological status of the individual with the wound and are helpful to provide comprehensive pain assessment. Anticipation is another important consideration and is especially relevant at dressing changes and will be discussed in more depth later.
Recognition that the differences in the response to pain is expected and that different people will experience pain differently is essential to the management of pain. The challenge for the wound care health care practitioner is to understand these multifarious issues and integrate all of them into a coherent pain and wound care strategy. This is especially true when recent evidence suggests that there is a relationship between pain and stress and that these influence wound healing22-24. One way to ensure that all aspects of pain management are covered is to utilise the Manchester P.A.I.N. model 25.
P.A.I.N model applied to wound pain
The Manchester model guides the practitioner through four key stages (Preparation, Assessment, Intervention and Normalisation) required for good pain management. Each stage includes different care needs dependent upon the type of wound being treated. For recurrent pain events using the model should be seen as a cyclic process with each stage being revisited to ensure that all aspects are covered. In more problematical wound pain each stage may need to be visited several times to ensure comprehensive coverage and successful management. It is understood that there are multiple different combinations of pain type and wound type so for clarity and brevity the model will be only be applied to three common wound care situations here. These are acute pain from acute wounds, chronic pain from chronic wounds and procedural pain of chronic wounds caused by dressing changes as it is considered that these three examples illustrate the major issues that practitioners will encounter on a day to day basis.
Acute pain of acute wounds
Preparation
Pain associated with acute wounds is generally the easiest to manage but still requires attention to detail to be successful. Preparation involves readying the patient for the pain experience. There is significant evidence that information prior to a procedure can reduce pain associated with that event 26. For post surgical wound pain this could be performed at pre-assessment clinics and be incorporated into the general post-operative information delivered at these important consultations 27. However as it is known that some patients react negatively to some forms of information hence the amount and detail of the information should be negotiated with the patient 28. Preparation of the practitioner treating the wound requires knowledge of the potential causes of pain in an acute wound. Overwhelmingly this will be due to nociception. Reaction to nociception however can be affected by social, psychological and spiritual characteristics so practitioners need to be vigilant to the potential suppression or magnification of pain resulting from traits inherent within the person with the wound during the assessment process 29.
Assessment
Assessment of pain in acute wounds requires thought and planning but due to the nature of the wound being a nociceptive event a uni-dimensional pain assessment tool is usually adequate. Visual analogue scales (VAS), numerical rating scores (NRS) and verbal rating scales (VRS) which all measure pain intensity are commonly used and are effective in this group 29 30. Pain assessment and reassessment strategies should continue until the wound is fully healed and should be measured during movement rather than at rest.
Intervention
Nociceptive pain from acute wounds can usually be treated with medication. In hospitals local anaesthetic blocks and wound infiltration are often used at the time of surgery and for patients who are likely to remain in hospital local anaesthetic infusions are now becoming common place 28. Following on from using local anaesthetics traditional analgesics such as acetaminophen (paracetamol), non-steroidal anti-inflammatories (NSAID’s) and opioids (morphine and its derivatives) are usually effective but must be utilised within their dose limits and taking account of contraindications. If the pain is sufficient for the use of an opioid then dose titration is necessary. Using paracetamol and an NSAID additional to an opioid will mean that lower doses of the opioid will be required 31. Controlling acute wound pain may mean that additional analgesia is not necessary when dressing changes are required however complex acute wounds such as those following the surgical treatment of an abscess which need regular packing will need similar strategies to those described below for procedural pain in chronic wounds. The aim of pain intervention is to enable full function or the earliest possible return back to normal (normalisation).
Normalisation
Normalisation needs to be at the forefront of all thinking during pain management of wounds. It recognises the need to ensure that the person with the wound should be able to function normally or optimally, depending upon the circumstances, despite the presence of the wound.
Chronic pain of chronic wounds
Preparation
When pain has been present for an extended period of time there are inevitable psychosocial consequences which means that the weighting of these factors in treatment strategies needs to be higher7. For instance it is documented that chronic pain is associated with significant levels of depression and anxiety 16. Practitioners treating chronic pain from chronic wounds need to be ready to utilise holistic strategies, hence the preparation phase for chronic wounds with chronic pain will involve the practitioner as much as the patient as they need to be extra vigilant of the biopsychosocial attributes of each individual. This involves being prepared for amongst other things, catastrophising/stoicism, depression/anxiety and the presence of allodynia/hyperalgesia from neuroplasticity as these will affect all stages of the PAIN model. Neuroplasticity can create clinical situations that appear irrational or counter-intuitive. An example could be that the skin for several centimetres around a chronic wound is painful to touch, indeed it is possible that the wound itself is insensate but the skin surrounding the wound is exquisitely painful.
Assessment
Taking account of the biopsychosocial factors influencing pain makes assessment of chronic pain more difficult than for acute wounds with acute pain. In chronic pain from a chronic wound a simple intensity scale is insufficient on its own. Instead a full assessment of the factors contributing to the pain is required. A full sociocultural assessment is required which will vary depending on the environment in which the assessment is being made, the therapeutic relationship, and the presence or absence of significant others. There are assessment tools for anxiety and depression such as the Hospital Anxiety and Depression Scale (HADS) 21, coping style including the coping strategies questionnaire (CSQ) 32 and catastrophizing (PCS) 17, and these can be used alongside a multidimensional pain assessment tool such as the McGill Pain Questionnaire (MPQ) 33 or the Brief Pain Inventory (BPI) 34. The multidimensional pain assessment tools will enable full capture of the pain and its effects on the person. Words such as sharp, throbbing and aching tend to be associated with nociceptive pain whereas words such as burning, shooting and ‘electric shocks’ tend to be associated with neuropathic pain. Neuropathic pain occurs when nerves are damaged and may also be associated with allodynia or hyperalgesia. This means that the assessment of pain in chronic wounds may require assessment of the skin surrounding the wound in order to ensure that the correct dressing and fixatives are utilised. If it is suspected that there is a neuropathic element to the pain then a specific neuropathic pain assessment tool such as the LANSS can be used35. Comprehensive and differential assessment taking account of all the biopsychosocial attributes is essential to guide accurate treatment strategies.
Intervention
With chronic wound pain management analgesics are often inadequate on their own. Additional attention to the psychosocial consequences of the pain is required alongside analgesics for comprehensive and effective pain management. Creative thinking is required by the practitioner to manipulate the psycho-socio-cultural-environmental influences extant upon the person with the chronic wound. Powerful social forces such as health beliefs (of the patient and their relatives/friends) and psychological traits such as catastrophizing which affect the pain experience can be worked upon within the therapeutic relationship built up between the practitioner and the patient as this is the principle of most pain management programmes in the UK 36. An over-riding requirement of this is consistency hence as far as possible for optimal care the same practitioner should be involved as much as possible in the wound/pain care.
The choice of analgesics is based upon the comprehensive assessment. Nociceptive elements should be targeted with paracetamol, NSAID’s and Opioids. These should be given regularly rather than on an ad hoc basis and titrated against the effect of the pain on function.
Neuropathic pain identified in the wound area may require adjuncts such as antidepressants and anticonvulsants 37 38. Commonly utilised antidepressants are amitriptyline and nortriptyline which are given at low dose compared to that used for depression and a good strategy especially for the anti-depressants is to deliver them at night because they can cause drowsiness. This side effect can be used constructively in people with chronic pain as it can help them to sleep and reducing sleep deprivation can have a significant positive effect on the pain as well 37. It is good practice to state clearly to the patient that the antidepressants are being utilised as analgesics and that their use does not make a statement as to their mood state. Gabapentin and pregabalin are anticonvulsants that are widely used for neuropathic pain with good efficacy data 39 40.