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Chapter 15

Pain Management

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Definition of Pain International Association for the Study of

Pain defines it as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage”

McCaffery, a nurse and leader in the pain management field, has a more useful definition for nurses: “Pain is whatever the person experiencing it says it is and exists whenever he says it does”

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Physiology of Pain Sensory experiences: time/space,

emotions, cognition Afferent pathways

◦ Nerves that carry messages to the brain for interpretation

Efferent (or descending) pathways ◦ Carry messages away from the brain via spinal

cord Nociceptors

◦ Receptors that activate the afferent pathways ◦ Unevenly distributed in muscles, tendons,

subcutaneous tissue, and the skin

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Physiology of Pain Pain receptors are sensitive to chemical

changes, temperature, mechanical stimuli, and tissue damage

Pain receptors are unable to adapt to repeated stimuli and thus continue to react until stimuli are removed

When pain receptors are stimulated, impulses are transmitted to the spinal cord

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Physiology of Pain Impulses then travel up the spinal cord to

the brain In the brain, the cortex interprets the

impulses as pain and identifies the location and qualities of the pain

Endorphins and enkephalins, natural opioid-like substances: block transmission of painful impulses to the brain

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Gate-Control Theory Pain reflects physical and psychosocial

factors Painful impulses are transmitted to the

spinal cord through small-diameter nerve fibers in the afferent pathway

When these fibers are stimulated, the gating mechanism opens in the spinal cord, which permits the transmission of impulses from the spinal cord to the brain

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Gate-Control Theory Factors that cause the gate to open

include tissue damage, a monotonous environment, and fear of pain

Stimulation of large-diameter fibers can close the gate and interfere with impulse transmission between spinal cord and the brain, causing diminished pain perception

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Figure 15-1

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Factors Influencing Response to Pain Although people may have the same injury

or insult, they may respond differently because many physical and psychosocial factors affect the response to pain

Important for health professionals to be nonjudgmental and to avoid comparing one individual in pain with another

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Physical Factors Pain threshold

◦ Point at which stimulus causes sensation of pain Pain tolerance

◦ Intensity of pain that a person will endure Age Physical activity and nervous system

integrity Surgery and anesthesia

◦ Type of surgery performed and the type of anesthesia used can influence the response to pain

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Psychological Factors Culture and ethnicity

◦ Different ways of expressing/responding to pain Religious beliefs

◦ Some patients may pray and believe that divine intervention will help them to endure the pain

◦ Others may view pain as a punishment for sins ◦ Some believe that suffering is required before

pain relief

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Psychological Factors Past experiences and anxiety

◦ May have developed positive coping strategies to deal with previous painful experiences

◦ If strategies were unsuccessful, may be very anxious and overwhelmed by another painful experience

Situational factors ◦ If pain associated with a serious illness, it may

have a greater effect on mood and activity than if the pain were associated with a less serious condition

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Autonomic Nervous System Activates the fight-or-flight response;

certain physiologic responses initiated The nervous system responses measured

by increased heart rate, respiratory rate, and blood pressure

Acute and chronic pain elicit different kinds of responses

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Acute Pain Follows the normal pathway for pain from

nociceptor activation to the brain and may be called nociceptive pain

Cause is known and treatable It serves as a warning of tissue damage

and subsides when healing takes place Behavioral and physiologic signs: when

patient guards or rubs a body part, wrinkles the brow, bites the lip, and has changes in the heart rate, blood pressure, and respiratory rate

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Chronic Pain Persists/recurs for >6 months; may last a

lifetime Most chronic pain is neuropathic pain because

it follows an abnormal pathway for pain Results from nerve damage from anatomic and

physiologic conditions and underlying diseases Includes unusual sensations such as burning,

shooting pain, and abnormal sensations that occur when there is no painful stimulus present

See Table 15-2, p. 206

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Comparison of Acute and Chronic Pain Chronic pain serves no useful purpose;

acute warns of tissue damage and trauma Nursing assessment to identify

◦ Type and amount of pain◦ Chronic or acute◦ If acute and chronic pain at the same time

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Figure 15-2

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Nursing Care of the Patient in Pain

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Assessment Should be done on admission and on a

regular basis Assessment of vital signs is called the fifth

vital sign

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Assessment Six steps

◦ Accept the patient’s report ◦ Determine the status of the pain◦ Describe the pain

Location, quality, intensity, aggravating and alleviating factors

◦ Examine the site of the pain ◦ Identify coping methods ◦ Document assessment findings and evaluate

interventions

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Figure 15-5

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Nonpharmacologic Interventions

Those that do not employ drugs Physical interventions

◦ Physical comfort measures◦ Environmental control◦ Stimulation techniques◦ Anxiety reduction◦ Distraction

Psychological interventions◦ Relaxation◦ Imagery

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Pharmacologic Interventions Nonopioid analgesics

◦Aspirin, acetaminophen, and nonsteroidal anti-inflammmatory drugs (NSAIDs) such as ibuprofen

◦Generally initial treatment choice for mild pain

◦Act mostly on the peripheral nervous system

◦Antipyretic (fever-reducing), analgesic (pain-reducing), and/or anti-inflammatory (inflammation-reducing) properties

◦See Table 15-4, p. 216

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Pharmacologic Interventions: Opioid Analgesics For moderate to severe acute pain, chronic

cancer pain, and some other types of pain Opioids: potency/duration of action vary Opioid agonists

◦ Examples: codeine, methadone (Dolophine), hydromorphone (Dilaudid), meperidine (Demerol), morphine, and fentanyl

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Pharmacologic Interventions: Opioid Analgesics Opioid agonist-antagonists

◦ Examples: buprenorphine (Buprenex), nalbuphine (Nubain), butorphanol (Stadol), and pentazocine (Talwin)

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Pharmacologic Interventions: Opioid Analgesic Misconceptions Patients, families, nurses, and physicians

have misconceptions about addiction; therefore, the term must be defined and differentiated from the terms tolerance and physical dependence

Tolerance and physical dependence are normal responses to continued opioid administration for pain relief; they do not lead to a craving for the drug for its mind-altering effects

Fear of addiction greatly exaggerated; rare (<1%) in patients taking opioids for pain relief

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Pharmacologic Interventions: Opioid Analgesics Routes of administration

◦Oral◦Intramuscular◦Sublingually◦Intravenously: intermittent bolus

injections, continuous infusions, or patient-controlled analgesia (PCA)

◦Epidural or intrathecal route

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Pharmacologic Interventions: Opioid Analgesics Side effects

◦ Constipation◦ Nausea, with or without vomiting◦ Sedation ◦ Respiratory depression ◦ Confusion◦ Hypotension (especially orthostatic)◦ Dizziness◦ Urinary retention

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Pharmacologic Interventions: Placebos Inactive substances (e.g., saline) used in

research or clinical practice to determine the effects of a legitimate drug or treatment

Appropriately used in studies in which patients consent to participate

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Pharmacologic Interventions: Placebos Many health care organizations take the

position that placebos should not be used to assess or manage pain

Nurses have ethical obligation to ensure that patients are not deceived and that institutional policies related to placebos are followed

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Pharmacologic Interventions: Adjuvant Analgesics and Medications

Drugs not usually classified as analgesics may relieve pain in certain situations

A patient who has undergone back surgery may complain more about muscle spasms than incisional pain ◦ A muscle relaxant may be more effective in

relieving pain than an opioid alone

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Pharmacologic Interventions: Adjuvant Analgesics and Medications

Specific pain syndromes, especially neuropathic, may be controlled with drugs other than the commonly known analgesics

See Table 15-6, p. 219

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Problem Solving with Pain Medication Patients whose prescribed analgesic drugs

do not relieve pain Ask questions about the analgesic drug

and the “five rights” (right dose, right patient, right time, right route, right analgesic) to determine why the patient is not getting adequate pain relief

See Box 15-8, p. 221