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Course Sample:
Part 1 Concepts in pain management One of the most urgent calls for improvement in quality of health care emerged from the overwhelming evidence that pain is undertreated in hospitals. Not surprising, infants and children have been identified as one of the most poorly managed groups for pain control (AHCPR, 1993). Some suggested reasons for this are because their pain is difficult to assess, there is unfounded fear of causing addiction, and there is poor understanding of the facts. As recently as twenty years ago it was believed that neonates and infants didnt experience pain and wouldnt remember it if they did. Now we know that: - All of the neural circuits required to sense and to remember pain are present well before 40 weeks post-conceptual age (Lemons, 2000)
- Unrelieved pain has negative physical and psychological consequences including exaggerated pain responses throughout life and increased morbidity (Porter, et al, 1999).
- Even though pain is undertreated for nearly all children, there are certain groups who are even more at risk, including: pre-term and full term infants, and cognitively impaired or emotionally impaired children (AHCPR, 1993).
- Pain can be assessed at all age groups, utilizing pain scales with appropriate indicators of pain that vary by age group.
- Analgesics can be safely utilized at all age groups, provided features of pharmacology and of pediatric physiology are understood.
- This continuing education program will provide a thorough review of current knowledge regarding the physiology, pharmacology and nursing approaches to effective pain management for infants and children.
CONCEPTS IN PAIN: Pain Defined Pain is defined as the conscious awareness of actual or potential tissue injury (AHCPR,1993). Perception of pain requires stimulation of afferent (ascending) nerve fibers to the spinal cord and their relay up the cord to cognitive centers. Physical, cognitive, emotional, cultural and social aspects all impact on the neurophysiologic transmission of pain, therefore it is very individually modified. There is no correct amount of pain for any particular stimulus. Knowing the many neural pathways involved in the pain experience helps the practitioner appreciate the multi-modal approach necessary for effective pain management. Pain Transmission Pain transmission begins at the site of injury with a complex cascade of events. Many endogenous chemicals (histamine, bradykinin, serotonin, substance P, and calcitonin gene-related peptide) are released (Raj, 1994). Many of these are the same chemical mediators of inflammation. The types and amounts of chemicals released will heavily influence the pain response. These chemicals stimulate afferent nerves in the surrounding tissue. Pain is spread to surrounding areas, extravasation and edema occur, and endogenous pain control measures are initiated (Raj, 1994). At the spinal cord the reflex arc results in peripheral release of more chemical mediators at the site of injury. Withdrawal from the source of injury is initiated, opioid receptors within the cord alter release of neurotransmitters to blunt the pain response, and pain is simultaneously transmitted up the spinal cord (Raj, 1994). The pain impulse stimulates many different brain regions. The sympathetic nervous system fight or flight response is stimulated, providing short-term benefits in the form of enhanced energy production. (But when pain is inadequately treated there is a prolonged sympathetic stress response that can lead to muscle wasting, fatigue, decreased infection resistance and compromised function of key organs [Fitzgerald & Anand,1993].) Stimulation of the somatosensory region provides cognitive recognition of the experience of pain. Within the frontal, parietal and limbic systems emotion, memory and cognition act to further modulate the experience of pain and to develop learned avoidance and conditioned responses to pain (Raj, 1994). It is important for nurses to understand that all pain has emotional, memory and cognitive components, as well as sensory and endocrine components. This is true at all ages, even in neonates. And even when pain cannot be expressed there are specific immediate and delayed responses that show there is memory of pain. Classifications of pain Classifications of pain exist to help define clinical situations and to guide clinical management. Acute pain is short term and is generally amenable to pharmacologic control. When it occurs in cutaneous or deep tissues it is typically constant, well localized and described as sharp, throbbing or gnawing, while acute pain resulting from injury to visceral organs is more characteristically vague in distribution and described as paroxysmal or colicky (Raj, 1994). With acute visceral pain there is sympathetic nervous system involvement that can produce nausea, vomiting, diaphoresis and alterations in blood pressure and heart rate. There may also be referred pain: a phenomenon of pain that is localized to tissues often distant from the site of the condition, like arm pain from angina or abdominal wall pain from peritoneal irritation (Raj, 1994). Chronic pain is not as well understood. It may occur as the end result of prolonged acute pain, even when the acute pain was treated appropriately. It often results in physiologic, anatomic and behavioral changes that persist even when the original source of pain is removed (Raj, 1994). Chronic pain generally requires a multi-modal approach to management that includes pharmacologic agents and psychological support. Psychogenic pain refers to the complex interaction of physiologic and psychological states. Anxiety is often the anticipation of acute pain. Its presence will increase the tendency to report mild pain as more severe and will increase sympathetic nervous system response to pain. Depression, anger, irritability and frustration are also common in acute and chronic pain. It is often difficult to tell whether a psychological state is the response to pain or the cause of the pain. Regardless, the perception is real to the patient (Raj, 1994). Neuropathic pain occurs when an element of the nervous system itself is injured. For example, a nerve itself may be compressed, a nerve plexus may be avulsed, or a post-infectious inflammatory process may produce chronic changes within a nerve fiber. It includes reflex sympathetic dystrophy and phantom pain. It may be extremely intolerable with sensations that are different from ordinary pain such as burning, tingling, numbing, pressing, squeezing or itching (Raj, 1994). The development of neuropathic pain is unpredictable even patients with similar lesions describe different phenomenon. It is also notoriously difficult to suppress with conventional therapies. Assessment scales One of the fundamental problems in providing adequate pain management is determining the degree of pain somebody is experiencing. Adults are usually able to articulate their pain, but infants and children may not. Several age-specific assessment tools have been developed to combat this problem. The gold standard for pain assessment scales is the self-report method. The scale most widely utilized with adults is the Visual Analogue Scale (VAS) (AHCPR, 1993). A plain line 10 cm. in length is labeled no pain at one end and worst possible pain on the other. Patients mark a point on the line that corresponds to their intensity of pain. Children who are 8-10 years or older are very capable of understanding and using this scale. Younger children do not have the cognitive capacity to understand the VAS. A self-report scale commonly used for children but also used for cognitively impaired adults, is the Faces scale (Wong, 1997). This consists of a series of pictures of faces ranging from calm and happy to maximally distressed. The child is asked to point to the face that corresponds most with how they feel on the inside. Children as young as 3 years of age are generally capable of understanding and using this scale successfully. It is not uncommon for the results of this scale to be surprising. Children, often stoic, may present to the nurse a calm and collected face, but will point to a face on the scale displaying much more discomfort. |
