The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [329]
Two-thirds of chronic pain sufferers surveyed in the UK reported inadequate pain control with only 16% saying they had seen a pain specialist. Despite the fact that many patients want more effective management and better understanding of their pain, 70% were very satisfied with the doctor who treats their pain.
(British Pain Society and Royal College of Physicians 2004)
Definition
Pain is difficult to define due to the complexity of its anatomical and physiological foundations, the experience and perceptions of each individual person and the social and cultural meanings of pain (Paz and Seymour 2008). It is not a simple sensation but a complex phenomenon, having both a physical and an affective (emotional) component. To reflect this, the International Association for the Study of Pain (IASP) 1994 published the following definition of pain: ‘An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’. Pain is subjective and another favoured definition for use in clinical practice, proposed originally by McCaffrey (1968) and cited in McCaffrey (2000), p.2), is: ‘Pain is whatever the experiencing person says it is, existing whenever the experiencing person says it does’.
Related theory
Many factors influence the expression of pain and may be associated with the patient, the nurse or the clinical environment (organizational aspects) (Carr and Mann 2000). Pain can have many dimensions including physical, psychological, spiritual and sociocultural.
There are several ways to categorize the types of pain that occur, for example, acute or chronic, nociceptive (somatic or visceral) or neuropathic. It is increasingly recognized that acute and chronic pain may represent a continuum rather than being distinct separate entities (Macintyre et al. 2010) and may combine different pain mechanisms and vary in duration.
Acute pain
The IASP has defined acute pain as: ‘Pain of recent onset and probable limited duration. It usually has an identifiable temporal and causal relationship to injury or disease’ (Ready and Edwards 1992, p.1). Acute pain is produced by a wide range of physiological processes, and includes inflammatory, neuropathic, sympathetically maintained, visceral and cancer pain (Walker et al. 2006). Acute pain serves a purpose by alerting the individual to a problem and acting as a warning of tissue damage or potential tissue damage. If left untreated, it may result in severe consequences; for example, not seeking help for acute abdominal pain may result in emergency care such as appendicitis progressing to peritonitis. Acute pain is short-term pain of less than 12 weeks’ duration (British Pain Society 2008). It occurs in response to any type of injury to the body and resolves when the injury heals.
Chronic pain
Chronic pain is usually prolonged and defined as pain that exists for more than 3 months, lasting beyond the usual course of the acute disease or expected time of healing (IASP 1996). It is often associated with major changes in personality, lifestyle and functional ability (Foley 2004). Chronic pain occurs as a result of both cancer and non-malignant chronic conditions such as neuropathic, musculoskeletal and chronic postoperative pain syndromes.
The term ‘breakthrough pain’ is widely used. Within the medical literature, other terms are used in the description of breakthrough pain including episodic pain, exacerbation of pain, pain flare, transient pain and transitory pain (Colleau 1999).
The ethos of this section will be based on acute and chronic pain management in cancer and palliative care patients. Many of the principles are transferable to other pain situations.
Anatomy and physiology
Pain mechanisms (anatomy and physiology) are usually