Page 111 Complete Your CE Test Online - Click Here Modulation Pain can be modulated in various ways. The gate control theory of pain by Melzack & Wall (1965) assumes that perceived pain could be either increased or decreased via a gate closing or opening at the dorsal horn of the spinal cord. The gate takes into account various sensory inputs; the gate is then opened or closed accordingly allowing or stopping the transmission of pain impulses. For example, when a person stubs her toe or bangs her elbow, she rubs the injured area and gets pain relief by interrupting the pain pathway through touch. Descending modulation is a process that occurs from pathways that descend from the forebrain and brain stem to the spinal cord. The periaqueductal gray (PAG) region receives information from higher brain centers and facilitates an analgesic effect (Ossipov, Morimura, & Porreca, 2014). The rostroventromedial medulla region (RVM) facilitates or inhibits nociceptive inputs that will result in pain or inhibit pain (Ossipov, Morimura, & Porreca). Serotonin, endogenous opioids, and norepinephrine are neurotransmitters released through descending modulation and interrupt pain impulses by stopping the release of substance P (a neurotransmitter for pain), thereby halting the transmission of the pain impulse (Copstead & Banasik, 2013). Physiology of pain relief The treatment of both acute and chronic pain uses both pharmacologic and nonpharmacologic approaches that work in the following ways (Copstead & Banasik, 2013). Interrupting the peripheral transmission of pain Examples include splinting to reduce further injury of tissue; applying heat or cold to reduce swelling; using pharmacologic agents, such as NSAIDS, that inhibit prostaglandin production; and local anesthetics that interrupt the pain pathway by blocking sodium from entering and interfering with the action potential. Modulating pain transmission at the spinal cord Examples include cutaneous stimulation that blocks progression of nociceptive transmission, such as transcutaneous electrical nerve stimulation (TENS), massage, acupuncture, therapeutic touch, and applying heat or cold to the area. Epidural and intrathecal analgesia— such as opioids, local anesthetics, and alpha-adrenergic blocking agents - act on the spinal cord to block pain. Opioids used in this way work by binding with opioid receptors, thereby decreasing the release of neurotransmitters, such as substance P. Intraspinal local anesthetics block nerve conduction. Alpha-adrenergic blocking agents work by blocking the transmission of mediated pain. Spinal column stimulators may be used for those with chronic pain and are thought to “close the gate” by altering the input descending from the brain to the spinal cord. Spinal column stimulators have minimal side effects and are indicated for patients who have neuropathic pain, such as those who have had failed back surgery or complex regional pain syndrome. Implantable pulse generators provide stimulation through electrodes placed into the epidural space (Verrills, Sinclair, & Barnard, 2016). Altering the perception and integration of pain Examples include opioids for moderate to severe pain and nonpharmacologic treatments, such as hypnosis, distraction, guided imagery, relaxation techniques, and biofeedback. Self-assessment question 3 Distraction is a technique that is thought to work by: a. Modulating pain transmission at the spinal cord. b. Altering the perception of pain. c. Interrupting peripheral transmission of pain. d. None of the above. Pain assessment A thorough pain assessment is key to understanding the extent and nature of a person’s pain and facilitates diagnosis and treatment. In addition to a thorough history and physical, the initial pain assessment should be well documented and include the following information (Institute for Clinical Systems Improvement, 2005; National Pharmaceutical Council [NPC], 2001): ● ● Pain location. ● ● Pain intensity (can utilize a pain scale, such as visual analog or numerical rating). ● ● What exacerbates the pain. ● ● What relieves the pain. ● ● The quality of the pain (throbbing, dull, sharp). ● ● Onset of pain. ● ● Duration of pain. ● ● If pain affects sleep. EBP alert! Individuals who have experienced abuse or neglect as children are at an increased risk of experiencing chronic pain as adults when compared to those who were not abused in childhood (Davis, Luecken, & Zautra, 2005). For those experiencing chronic pain, the nurse will want to know if there is a history of depression or anxiety; if there was any past physical, sexual, or emotional abuse; and if there is a history of chemical dependence. Pain assessment should take place on admission to the hospital or visit to a health care provider; if a change in mental status is noted; and before, during, and after any procedure that could provoke pain (Registered Nurses’Association of Ontario [RNAO], 2013). Acute pain should also be assessed after the administration of pain medication and on a regular basis as determined by workplace policy. Nursing consideration: Depression is common with ongoing pain and may require a referral to a specialist (ICSI, 2005). The nurse or other health care provider should screen patients for depression who are experiencing chronic pain. Pain scales Numerous pain scales are available to nurses that help patients quantify their pain experience. Visual pain scales are useful for children over age 3 and for the cognitively impaired. An example of a visual pain scale is the Wong-Baker Scale, which utilizes a series of faces starting with a smiling face indicating no pain, to a crying face that indicates the most severe pain. In patients 8 years to adulthood, a numerical scale may be used to assess pain, such as the Visual Analog Scale, which asks a patient to rate his pain on a scale of 0 to 10, with 0 no pain and 10 the worst pain. The revised FLACC Scale is effective for assessing pain in ages 2 months to 7 years in patients unable to rate their pain or use a face scale (Merkel, Voepel-Lewis, & Malviya, 2002):