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Nursing care of patients in pain: an age-old solution

Ramon Pediani
RN BSc(Hons) PhD
Honorary Postdoctoral Research Fellow
University College of St Martin
Lancaster

The author did a presentation ­entitled "The Nurse's Role in Pain Management" in the "Pain and Chronic Wounds" section of the 12th Conference of the European Wound Management Association in May 2002

This is the second of two articles looking at providing appropriate nursing care to patients in pain. The first article focused on the continued and erroneous fear that nurses have of causing addiction when providing painkillers, the multitude of factors that affect the patients' experiences of pain, and the practical difficulties that surround meaningful pain assessment.(1) The case was made that these problems had been known about for the past 20-30 years, and this second article aims to show that many of the possible solutions have also been known about for at least the length of most nurses' careers.

Nonpharmacological methods
Basic nursing skills of listening and comforting may help the patient to cope, but good nursing care is not a substitute for the administration of appropriate and effective analgesics - but then, neither are analgesics alone sufficient to ensure the total wellbeing of the patient. In 1975 Hayward showed that the provision of relevant information not only reduces stress, but also reduces the analgesic requirement.(2) The use of psychological techniques such as "cognitive coping",(3) have been shown to reduce psychological distress and have profoundly beneficial effects on the physical and psychological wellbeing of patients experiencing pain. A review of the research into the nursing contribution to pain management in 1984 highlighted the ­importance of nurse-patient interactions.(4)
According to a specific review of the literature on pain and anxiety,(5) it is far from settled that reducing anxiety by relaxation directly reduces pain. In this study pain was electrically stimulated in 55 subjects, and anxiety (high versus low) and attention (attention versus distraction from the pain) were manipulated experimentally. The findings showed that it was attention rather than anxiety that is related to stronger pain responses. The artificial circumstances may be far removed from the clinical environment, and as the authors point out the findings do not mean that anxiety is never relevant to clinical pain. When a person is anxious about the causes or the time course of the pain he or she may pay more attention to that pain, thereby increasing their perception of it.
Much of what nurses do in the delivery of nursing care, according to the "Gate Control Theory",(6) is to close the "pain gate". They can achieve this by simple techniques that involve relaxation, suggestion or distraction. Hypnosis, deep breathing techniques, acupuncture, music, touch, massage, reflexology and aromatherapy can all aid comfort and rest. These techniques have the advantage over pharmacological methods in that they have no drug and minimal equipment cost, they are reversible, and have few adverse effects.(7) However, there are costs associated with aromatherapy oils and the training requirements for nursing staff to utilise them safely. The application of these techniques also has labour time implications.

Opioids
The juice of the poppy has been known for its psychological effects since ancient times - Jaffe and Martin provide a brief history of its use since the middle of the 16th century.(8) The unrestricted availability of opium up until 100 years ago led to problems of abuse and addiction that have "constrained the medical use of opioids to this day". Over the 1960s and 1970s research from various teams established the physiological basis for understanding the mechanisms of action of opioids.
Drugs such as morphine activate opioid receptors in the dorsal horn of the spinal cord and have an inhibitory role in the transmission of pain signals. Opioids are CNS depressants and, as well as reducing the perception of pain, can give rise to respiratory depression and induce drowsiness and coma in high doses.(9) There needs to be a balance between fine-tuning the optimum dose of opioid to reduce pain, and avoiding the ­development of potentially serious side-effects.
Orally administered opioids undergo extensive first-pass metabolism in the liver, and as little as 20-30% of the orally administered dose is available for systemic circulation.(10) For this reason, and also because many patients are "nil-by-mouth" following surgery, parenteral routes of administration are often preferred for acute pain. However, there is known to be a large variability in the rate of absorption of intramuscularly administered drugs. Morphine has been shown to take between 4 and 60 minutes to reach peak plasma levels ,(11) but the development of intravenous "patient-controlled analgesia" (PCA) allows for individual titration by the patient. More recently, the opioid fentanyl has become available as a transdermal patch and as an oral lollipop. These are used to provide constant background analgesia for cancer and chronic pain, with the faster-acting oral fentanyl providing rapid breakthrough doses. All routes of administration have their merits but the potential for unwanted side-effects is also present. Mostly these relate to the common irritant effects (nausea, drowsiness, itching and constipation), but excessive sedation and respiratory depression can result from overdose.
The idea that one analgesic dose schedule can suit all patients has been out of line with the available knowledge of pharmacology and interpatient variability for over 30 years. However, one notable success was described in which analgesia was tailored precisely to the individual's requirements through hourly pain assessment.(12) Although this relied on the intramuscular route of administration, it did allow nurses to give injections according to the patient's needs rather than a "one-size-fits-all" prescription. The approach used in this study is an example of medical and pharmacological knowledge being applied in a nursing environment, and where the nurses were empowered to make choices based on meaningful interaction with patients and were supported by departmental policy and training initiatives. Similar strategies can be designed to allow more flexible oral administration based on the patients' evaluation of how well the medicine is working, and within the safety parameters of the drug.
 
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Insel described how a number of "aspirin-like" compounds, although often chemically unrelated, share certain therapeutic actions and side-effects.(13) This article provides a historical account of the refinement from willow bark of the active ingredient, salacin, in 1829 to the discovery by Vane et al in 1971 of the inhibitory action of aspirin-like drugs on the production of inflammatory prostaglandins. By inhibiting cyclo-oxygenase (COX), the enzyme responsible for the formation of prostaglandins in areas of local tissue damage, they dampen inflammation and reduce pain stimulation effects of inflammatory mediators such as bradykinins and substance P on the pain-sensing nerve endings (nociceptors). Some NSAIDs and paracetamol (which has antipyretic and analgesic but not anti-­inflammatory effects) also have a central analgesic action.(14)
NSAIDs, however, also have adverse effects - most commonly gastric irritation - and so have to be used with caution in patients with a history of duodenal ulceration. NSAIDs also interfere with prostaglandin synthesis in other areas of the body such as the kidney, leading to a risk of renal failure, particularly in elderly and dehydrated patients following surgery. NSAIDs also affect clotting times. The use of NSAIDs for acute pain, which is normally of shorter duration than pain associated with chronic conditions such as rheumatoid arthritis, providing there are no contraindications in a specific individual, is recommended.(15) More recently we have seen the development of "COX-2"-specific NSAIDs which are reported to have an increased safety profile over the older non-specific NSAIDs, particularly with regard to their effects on the stomach and kidneys.(16)

Local anaesthetics
Murdoch-Ritchie and Greene have provided a historical account of the development of local anaesthetics from the isolation of cocaine in 1860 to the first synthetic substitute, procaine, in 1905.(17) Local anaesthetics interrupt the transmission of pain signals by blocking voltage-sensitive sodium channels in the axonal membrane. The threshold for the generation and conduction of impulses is increased and propagation of pain signals is effectively stopped, preventing the central perception of painful stimuli from the periphery.
Local anaesthetics can be administered peripherally for short procedural pain relief, or nerves can be anaesthetised by regional nerve block techniques, where a catheter is left alongside a nerve and a local anaesthetic instilled around it. Epidural and spinal administration of local anaesthetics gives access to major nerve roots where pain signals from a wide surgical field can be blocked, before they enter the spinal cord.
Compared with the two previous pharmacological options, opioids and NSAIDs, local anaesthetic pain control is the most technical and often requires medical assistance to apply. When pain is severe and difficult to control, however, it must be considered as an option because it is the most effective method. The others diminish pain to some degree, but a local block to treat the pain of, say, fractured ribs or a fractured hip, some cancer pains and pain following invasive procedures, is unparalleled.
 
Entonox
Nitrous oxide (N(2)O) gas was discovered over 200 years ago. It has been known to have analgesic and sedative properties since 1799, when Humphry Davy inhaled the gas and found it very pleasant, so much so that he knocked himself out and awoke laughing when trying to explain the pleasurable feelings he'd experienced.(18) This gave rise to its common name - "laughing gas".
It was only in the 1960s and 1970s that it became readily available in obstetric units and on ambulances as a medicinal gas in a 50:50 combination with oxygen. In the UK it is known as Entonox(®) from BOC. The gas was perhaps the original "patient-controlled analgesia" as the patient's ability to hold the facemask or mouthpiece and inhale the gas determines whether or not the demand valve activates. If the patient becomes too drowsy they will break the seal with their mouth and breathe normally - the lack of negative pressure prevents the gas valve from opening and shuts off the supply. Entonox wears off rapidly and has few short-term side-effects. It is therefore ideal for procedural pain relief in a wide variety of situations, including dressing changes, the removal of drains and traction pins, and endoscopy. It does have some clear contraindications, such as when there is trapped air in the body, for example in the case of a pneumothorax.(19)
Perhaps its association with childbirth or accidental trauma has led to nurses thinking it could not be made available to other patients. Misconceptions about the old "extended role" view of nursing tasks and a lack of awareness and confidence on the part of the nurse have been suggested as reasons why this excellent resource has been underutilised.(20)

Balanced analgesia
Different but complementary analgesic techniques used at the same time can provide "balanced" analgesia. Local anaesthetics, opioids, NSAIDs and Entonox all work in different ways to give a powerful combined result. The pain relief can be much greater than if ­relying on any single analgesic agent, because different points in the pain pathway are targeted simultaneously.(21) Smaller doses of individual drugs can be used, which reduces the incidence and severity of adverse effects.
It has been shown that the use of NSAIDs can result in a reduction in the requirement for opioids - typically by as much as 20-40% .(22,23) If a patient taking only opioid analgesia is reasonably comfortable, but is feeling sick, itchy and dizzy, the nurse or doctor may not automatically think to give another pain killer. By giving an NSAID or paracetamol, however, the patient's subsequent opioid requirement may be reduced, minimising the severity of the opioid side-effects. Such "balanced" analgesia using opioids and NSAIDs has been considered to be "quality" analgesia.(24) Similarly, the combination of local ­anaesthetics and opioids in an epidural infusion mixture has long been known to provide good analgesia at lower concentrations of either drug than if used alone.(25,26)
The technique of local anaesthetic wound perfusion has been explored in the control of postoperative pain, and reductions of opioid analgesic requirements of up to 50% were shown by Thomas et al in 1983.(27) This technique involves placing a fine catheter into the surgical wound at the end of operation and continuously infusing a local anaesthetic. It has been shown to be both effective and to carry little risk of infection.
Entonox can be given alongside other analgesics. The gas wears off within minutes and some forethought needs to be given to postprocedure pain relief. Oral opioids such as morphine elixir or paracetamol with codeine should be given at least one hour before the start of the procedure to allow them time to be absorbed and take effect.

Summary
The knowledge and understanding of the great variety in individual responses to pain, and the variable effectiveness of analgesic drugs in specific individuals, is unquestionable. Much of this has been known for many years, but perhaps a combination of poor training and the culture of nursing and medicine had left many nurses in the past ill-equipped to deal with their patients' pain problems. Now that many of the pieces of the jigsaw are falling into place, clinical practice has no excuses for lagging behind the vast amount of literature on the topic - not all of which is theoretical. The practical clinical focus of many papers shows clear evidence of great improvements taking place simply through the sensitive, individualised titration of the juice of the poppy and the extract of the willow bark, by the caring nurse who is prepared to spend a little extra time to listen to the patient.

References

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