If pain can be defined as a highly unpleasant, individualized experience of one of the body's defense mechanisms indicating an injury or problem, pain management encompasses all interventions used to understand and ease pain, and, if possible, to alleviate the cause of the pain.
Pain serves to alert a person to potential or actual damage to the body. The definition for damage is quite broad: pain can arise from injury as well as disease. After the message is received and interpreted, further pain can be counterproductive. Pain can have a negative impact on a person's quality of life and impede recovery from illness or injury, thus contributing to escalating health care costs. Unrelieved pain can become a syndrome in its own right and cause a downward spiral in a person's health and outlook. Managing pain properly facilitates recovery, prevents additional health complications, and improves an individual's quality of life.
Yet, the experiencing of pain is a completely unique occurrence for each person, a complex combination of several factors other than the pain itself. It is influenced by:
The perception of pain is an individual experience. Health care providers play an important role in understanding their patients' pain. All too often, both physicians and nurses have been found to incorrectly assess the severity of pain. A study reported in the Journal of Advanced Nursing evaluated nurses' perceptions of a select group of white American and Mexican-American women patients' pain following gallbladder surgery. Objective assessments of each patient's pain showed little difference between the perceived severities for each group. Yet, the nurses involved in the study consistently rated all patients' pain as less than the patients reported, and with equal consistency, believed that better-educated women born in the United States were suffering more than less-educated Mexican-American women. Nurses from a northern European background were more apt to minimize the severity of pain than nurses from eastern and southern Europe or Africa. The study indicated how health care staff, and especially nursing staff, need to be aware of how their own background and experience contributes to how they perceive a person's pain.
In a 1990 study reported in the journal Pain, nurses were found to overestimate the severity of pain in patients with severe burns. In most other studies, nurses and physicians ascribe a lower pain severity than do patients.
Before considering pain management, a review of pain definitions and mechanisms may be useful. Pain is the means by which the peripheral nervous system (PNS) warns the central nervous system (CNS) of injury or potential injury to the body. The CNS comprises the brain and spinal cord, and the PNS is composed of the nerves that stem from and lead into the CNS. PNS includes all nerves throughout the body, except the brain and spinal cord. Pain is sometimes categorized by its site of origin, either cutaneous (originating in the skin of subcutaneous tissue, such as a shaving nick or paper cut), deep somatic pain (arising from bone, ligaments and tendons, nerves, or veins and arteries), or visceral (appearing as a result of stimulation of pain receptor nerves around organs such as the brain, lungs, or those in the abdomen).
A pain message is transmitted to the CNS by special PNS nerve cells called nociceptors, which are distributed throughout the body and respond to different stimuli depending on their location. For example, nociceptors that extend from the skin are stimulated by sensations such as pressure, temperature, and chemical changes.
When a nociceptor is stimulated, neurotransmitters are released within the cell. Neurotransmitters are chemicals found within the nervous system that facilitate nerve cell communication. The nociceptor transmits its signal to nerve cells within the spinal cord, which conveys the pain message to the thalamus, a specific region in the brain.
Once the brain has received and processed the pain message and coordinated an appropriate response, pain has served its purpose. The body uses natural painkillers, called endorphins, to derail further pain messages from the same source. However, these natural painkillers may not adequately dampen a continuing pain message. Also, depending on how the brain has processed the pain information, certain hormones such as prostaglandins may be released. These hormones enhance the pain message and play a role in immune system responses to injury, such as inflammation. Certain neurotransmitters, especially substance P and calcitonin gene-related peptide, actively enhance the pain message at the injury site and within the spinal cord.
Pain is generally divided into two additional categories: acute and chronic. Nociceptive pain, or the pain that is transmitted by nociceptors, is typically called acute pain. This kind of pain is associated with injury, headaches, disease, and many other conditions. Response to acute pain is made by the sympathetic nervous system (the nerves responsible for the fight-or-flight response of the body). It normally resolves once the condition that precipitated it is resolved.
Following some disorders, pain does not resolve. Even after healing or a cure has been achieved, the brain continues to perceive pain. In this situation, the pain may be considered chronic. Chronic pain is within the province of the parasympathetic nervous system, and the changeover occurs as the body attempts to adapt to the pain. The time limit used to define chronic pain typically ranges from three to six months, although some health care professionals prefer a more flexible definition, and consider chronic pain as pain that endures beyond a normal healing time. The pain associated with cancer; persistent and degenerative conditions; and neuropathy, or nerve damage, is included in the chronic category. Also, unremitting pain that lacks an identifiable physical cause such as the majority of cases of low back pain may be considered chronic. The underlying biochemistry of chronic pain appears to be different from regular nociceptive pain.
It has been hypothesized that uninterrupted and unrelenting pain can induce changes in the spinal cord. In the past, severing a nerve's connection to the CNS has treated intractable pain. However, the lack of any sensory information being relayed by that nerve can cause pain transmission in the spinal cord to go into overdrive, as evidenced by the phantom limb pain experienced by amputees. Evidence is accumulating that unrelenting pain or the complete lack of nerve signals increases the number of pain receptors in the spinal cord. Nerve cells in the spinal cord may also begin secreting pain-amplifying neurotransmitters independent of actual pain signals from the body. Immune chemicals, primarily cytokines, may play a prominent role in such changes.
Considering the different causes and types of pain, as well as its nature and intensity, management can require an interdisciplinary approach. The elements of this approach include treating the underlying cause of pain, pharmacological and non-pharmacological therapies, and some invasive (surgical) procedures.
Treating the cause of pain underpins the idea of managing it. Injuries are repaired, diseases are diagnosed, and certain encounters with pain can be anticipated and treated prophylactically (by prevention). However, there are no guarantees of immediate relief from pain. Recovery can be impeded by pain and quality of life can be damaged. Therefore, pharmacological and other therapies have developed over time to address these aspects of disease and injury.
PHARMACOLOGICAL OPTIONS. General guidelines developed by the World Health Organization (WHO) have been developed for pain management. These guidelines operate upon the following three-step ladder approach:
Although antidepressant drugs were developed to treat depression, it has been discovered that they are also effective in combating chronic headaches, cancer pain, and pain associated with nerve damage. Antidepressants that have been shown to have analgesic (pain-reducing) properties include amitriptyline (Elavil), trazodone (Desyrel), and imipramine (Tofranil). Anticonvulsant drugs share a similar background with antidepressants. Developed to treat epilepsy, anticonvulsants were found to relieve pain as well. Drugs such as phenytoin (Dilantin) and carbamazepine (Tegretol) are prescribed to treat the pain associated with nerve damage.
Close monitoring of the effects of pain medications is required in order to assure that adequate amounts of medication are given to produce the desired pain relief. When a person is comfortable with a certain dosage of medication, oncologists typically convert to a long-acting version of that medication. Transdermal fentanyl patches (Duragesic) are a common example of a long-acting opioid drug often used for cancer pain management. A patch containing the drug is applied to the skin and continues to deliver the drug to the person for typically three days. Pumps are also available that provide an opioid medication upon demand when the person is experiencing pain. By pressing a button, they can release a set dose of medication into an intravenous solution or an implanted catheter. Another mode of administration involves implanted catheters that deliver pain medication directly to the spinal cord. Because these pumps offer the patient some degree of control over the amount of analgesic administered, the system, commonly called patient controlled analgesia (PCA), reduces the level of anxiety about availability of pain medication. Delivering drugs in this way can reduce side effects and increase the effectiveness of the drug. Research is underway to develop toxic substances that act selectively on nerve cells that carry pain messages to the brain. These substances would kill the selected cells and thus stop transmission of the pain message.
NON-PHARMACOLOGICAL OPTIONS. Pain treatment options that do not use drugs are often used as adjuncts to, rather than replacements for, drug therapy. One of the benefits of non-drug therapies is that an individual can take a more active stance against pain. Relaxation techniques such as yoga and meditation are used to focus the brain elsewhere than on the pain, decrease muscle tension, and reduce stress. Tension and stress can also be reduced through biofeedback, in which an individual consciously attempts to modify skin temperature, muscle tension, blood pressure, and heart rate.
Participating in normal activities and exercising can also help control pain levels. Through physical therapy, an individual learns beneficial exercises for reducing stress, strengthening muscles, and staying fit. Regular exercise has been linked to production of endorphins, the body's natural painkillers.
Acupuncture involves the insertion of small needles into the skin at key points. Acupressure uses these same key points, but involves applying pressure rather than inserting needles. Both of these methods may work by prompting the body to release endorphins. Applying heat or being massaged are very relaxing and help reduce stress. Transcutaneous electrical nerve stimulation (TENS) applies a small electric current to certain parts of nerves, potentially interrupting pain signals and inducing release of endorphins. To be effective, use of TENS should be medically supervised.
INVASIVE PROCEDURES. There are three types of invasive procedures that may be used to manage or treat pain: anatomic, augmentative, and ablative. These procedures involve surgery, and certain guidelines should be followed before carrying out a procedure with permanent effects. First, the cause of the pain must be clearly identified. Next, surgery should be done only if noninvasive procedures are ineffective. Third, any psychological issues should be addressed. Finally, there should be a reasonable expectation of success.
Anatomic procedures involve correcting the injury or removing the cause of pain. Relatively common anatomic procedures are decompression surgeries such as repairing a herniated disk in the lower back or relieving the nerve compression related to carpal tunnel syndrome. Another anatomic procedure is neurolysis, also called a nerve block, which involves destroying a portion of a peripheral nerve.
Augmentative procedures include electrical stimulation or direct application of drugs to the nerves that are transmitting the pain signals. Electrical stimulation works on the same principle as TENS. In this procedure, instead of applying the current across the skin, electrodes are implanted to stimulate peripheral nerves or nerves in the spinal cord. Augmentative procedures also include implanted drug-delivery systems. In these systems, catheters are implanted in the spine to allow direct delivery of drugs to the CNS.
Ablative procedures are characterized by severing a nerve and disconnecting it from the CNS. However, this method may not address potential alterations within the spinal cord. These changes perpetuate pain messages and do not cease, even when the connection between the sensory nerve and the CNS is severed. With growing understanding of neuropathic pain and development of less invasive procedures, ablative procedures are used less frequently. However, they do have applications in select cases of peripheral neuropathy, cancer pain, and other disorders.
Prior to beginning management, pain is thoroughly evaluated. Pain scales or questionnaires are used to attach an objective measure to a subjective experience. Objective measurements allow health care workers to better understand the pain being suffered by the patient. Evaluation also includes physical examinations and diagnostic tests to determine underlying causes. Some evaluations require assessments from several viewpoints, including neurology, psychiatry and psychology, and physical therapy. If pain is due to a medical procedure, management consists of anticipating the type and intensity of associated pain and managing it preemptively.
Nurses or physicians often take what is called a pain history. This will help to provide important information that can help health care providers to better manage the patient's pain. A typical pain history includes the following questions:
An assessment by nursing staff as well as other health care providers should be made to determine the effectiveness of the pain management interventions employed. There are objective, measurable signs and symptoms of pain that can be looked for. The goal of good pain management is the absence of these signs. Signs of acute pain include:
Signs of chronic pain include:
When these signs are absent and the patient appears to be comfortable, health care providers can consider their interventions to have been successful. It is also important to document interventions used, and which ones were successful.
Owing to toxicity over the long term, some drugs can only be used for acute pain or as adjuncts in chronic pain management. NSAIDs have the well-known side effect of causing gastrointestinal bleeding, and long-term use of acetaminophen has been linked to kidney and liver damage. Other drugs, especially narcotics, have serious side effects such as constipation, drowsiness, and nausea. Serious side effects can also accompany pharmacological therapies; mood swings, confusion, bone thinning, cataract formation, increased blood pressure, and other problems may discourage or prevent use of some analgesics .
Non-pharmacological therapies carry little or no risks. However, it is advised that individuals recovering from serious illness or injury consult with the health care providers or physical therapists before making use of adjunct therapies. Invasive procedures carry risks similar to other surgical procedures, such as infection, reaction to anesthesia, and iatrogenic (injury as a result of treatment) injury.
A traditional concern about narcotics use has been the risk of promoting addiction. As narcotic use continues over time, the body becomes accustomed to the drug and adjusts normal functions to accommodate to its presence. Therefore, to elicit the same level of action, it is necessary to increase dosage over time. As dosage increases, an individual may become physically dependent on narcotic drugs.
However, physical dependence is different from psychological addiction. Physical dependence is characterized by discomfort if drug administration suddenly stops, while psychological addiction is characterized by an overpowering craving for the drug for reasons other than pain relief. Psychological addiction is a very real and necessary concern in some instances, but it should not interfere with a genuine need for narcotic pain relief. However, caution must be taken with people who have a history of addictive behavior.
Effective application of pain management techniques reduces or eliminates acute or chronic pain. This treatment can improve an individual's quality of life and aid in recovery from injury and disease.
Kozier, Barbara, Glenora Erb, Kathleen Blais, and Judith M. Wilkinson. Fundamentals of Nursing, Concepts, Process and Practice, 5th edition. Redwood City, CA: Addison-Wesley, 1995.
Salerno, Evelyn, and Joyce S. Willens, eds. Pain Management Handbook: An Interdisciplinary Approach. St. Louis: Mosby, 1996.
Choiniere, M., R. Melzack, N. Girard, J. Rondeau, and M. J. Paquin. "Comparisons between Patients' and Nurses' Assessment of Pain and Medication Efficacy in Severe Burn Injuries." Pain 40, no.2 (February 1990): 143–52.
Everett, J. J., D. R. Patterson, J. A. Marvin, B. Montgomery, N. Ordonez, and K. Campbell. "Pain Assessment from Patients with Burns and Their Nurses." Journal of Burn Care Rehabilitation 15, no.2 (Mar–Apr 1994): 194–8.
McPherson, M. L., C. D. Ponte, and R. M. Respond (eds.). "Profiles in Pain Management." Journal of the American Pharmacists Association (June 2003).
American Chronic Pain Association. P.O. Box 850, Rocklin, CA 95677-0850. (916) 632-0922. http://members.tripod.com/~widdy/acpa.html .
American Pain Society. 4700 West Lake Ave., Glenview, IL 60025. (847) 375-4715. http://www.ampainsoc.org .
National Chronic Pain Outreach Association, Inc. P.O. Box 274, Millboro, VA 24460-9606. (540) 597-5004.
What We Know About Pain. National Institute of Dental Research, National Institute of Health, Bethseda, MD 20892. (301) 496-4261.
Joan M. Schonbeck Sam Uretsky, PharmD