Pain Management
What is it?
Lisa M. Lackner, RN, MSN
Pain…
What is the real definition of pain?
And what is pain management??
How can this information help me???
Pain
Definitions:
An unpleasant sensory and emotional experience
associated with actual or potential tissue damage.
Pain is whatever the experiencing person says it is.
May not be directly proportional to amount of tissue
injury.
Highly subjective, leading to undertreatment
Types of Pain
• 1. Acute
• 2. Cancer
• 3. Chronic non-malignant
Major Categories of Pain
Classified by inferred pathophysiology:
1. Nociceptive pain (stimuli from somatic
and visceral structures)
2. Neuropathic pain (stimuli abnormally
processed by the nervous system)
Anatomy and Physiology of
Nociceptive Pain
• 4 Basic Processes
• Transduction—nociceptors free nerve endings
with the capacity to distinguish between noxious
and innocuous stimuli. When exposed to
mechanical (incision or tumor growth), thermal
(burn), or chemical (toxic substance) stimuli,
tissue damage occurs. Substances are released by
the damaged tissue which facilitates the movement
of pain impulse to the spinal cord.
Substances released…
• The substances released from the
traumatized tissue are:
prostaglandins
bradykinin
serotonin
substance P
histamine
So, for instance
• Non-steroidal anti-inflammatories, such as
ibuprofen, are effective in minimizing pain
because they minimize the effects of these
substances released, especially
prostaglandins. Corticosteroids, such as
dexamethasone used for cancer pain, also
interferes with the production of
prostaglandins.
Transduction (cont.)
• Sufficient amounts of noxious stimulation cause
the cell membrane of the neuron (nervous system
cell) to become permeable to sodium ions,
allowing the ions to rush into the cell and creating
a temporary positive charge. Then potassium
transfers back into the cell, thus changing the
charge back to a negative one. With this
depolariztion and repolarization, the noxious
stimuli is converted to an impulse. This impulse
takes just milliseconds to occur.
• Some analgesics relieve pain primarily by
decreasing the sodium and potassium
transfers at the neuron level, thereby
slowing or stopping pain transmission.
Examples—local anesthetics,
anticonvulsants used for neuropathic pain,
migraines.
Process #2—Transmission
• Impulse spinal cord brain stem
thalamus central structures of brain
pain is processed.
• Neurotransmitters are needed to continue
the pain impulse from the spinal cord to the
brain—opioids (narcotics) are effective
analgesics because they block the release of
neurotransmitters
Process #3—Perception of Pain
• The end result of the neural activity of pain
transmission
• It is believed pain perception occurs in the cortical
structures—behavioral strategies and therapy can
be applied to reduce pain. Brain can accommodate
a limited number of signals—distraction, imagery,
relaxation signals may get through the gate,
leaving limited signals (such as pain) to be
transmitted to the higher structures.
Process #4—Modulation of Pain
• Changing or inhibiting pain impulses in the
descending tract (brain spinal cord)
• Descending fibers also release substances such as
norepinephrine and serotonin (referred to as
endogenous opioids or endorphins) which have the
capability of inhibiting the transmission of
noxious stimuli. Helps explain wide variations of
pain among people.
• Cancer pain responds to antidepressants which
interfere with the reuptake of serotonin and
norepinephrine which increases their availability
to inhibit noxious stimuli.
Pain
Neuropathic Pain
• Abnormal processing of the impulses either by the
peripheral or central nervous system
• May be caused by injury (amputation and
subsequent phantom limb pain), scar tissue from
surgery (back surgery high risk), nerve entrapment
(carpal tunnel), or damaged nerves (diabetic
neuropathy)
• Unclear why depolarization and transmission of
pain impulse are spontaneous and repetitive
Pain Language
• Acute pain: lasts less than 6 months, subsides
once the healing process is accomplished.
• Chronic pain: involves complex processes and
pathology. Usually involves altered anatomy and
neural pathways. It is constant and prolonged,
lasting longer than 6 months, and sometimes, for
life.
…more pain language…
Narcotic—obsolete term used to refer to what
is now called opioid. Current usage is
primarily in a legal context to refer to a
wide variety of substances of potential
abuse.
Pain…
• Amplifies the body’s stress response to
traumatic injury
• Causes endocrine and metabolic
abnormalities
• Impedes a patient’s recovery from trauma
and surgery
• Why treat pain?
• Tissue damage has the potential to elicit
mechanisms that can create disabling,
refractory, chronic situations that may
prolong and even outlast the period of
healing.
Hedderich & Ness, 1999
Several Pain Theories
Theory #1
Cousins’ Theory of Pathophysiology of Acute Pain
Severe, unrelieved acute pain results in abnormally
enhanced physiological responses that lead to
pronounced and progressively increasing
pathophysiology
 Pathophysiology  significant organ
dysfunction  morbidity and mortality
Harmful Effects
Cardiovascular and respiratory systems are
significantly affected by the
pathophysiology of pain
• adrenergic stimulation
• hypercoagulation, leading to DIC
•  heart rate
•  cardiac output
•  myocardial oxygen consumption
Pathophysiology of Pain (cont.)
•
•
•
•
•
 pulmonary vital capacity
 alveolar ventilation
functional residual capacity
arterial hypoxemia
suppression of immune functions,
predisposing trauma patients to wound
infections and sepsis
Theories of Pain #2
Selye’s Theory of Stress and General Adaptation
Syndrome
• During the initial assault (traumatic injury and
accompanying pain), a concentration of effort at
site of demand occurs.
• Adaptive responses attempt to achieve
homeostasis
•  epinephrine and catecholamines released
The Stage of Alarm
The Stage of Resistance
(everything is being used up)
• Energy
• Nutrients
• Oxygen
The Stage of Exhaustion
(homeostasis vs. death)
• The body can no longer sustain its adaptive
responses
• Devastating sequelae
• Irreversible organ damage and death of the
patient
So what?
Trauma patients perceive pain as much of a
stressor as the injury itself and marshal the
same physiological responses
Pain can kill you
Theory #3
Neuman Systems Model
• Individuals possess a unique central core of
survival factors
• Individuals possess lines of defenses which
attempt to keep the individual in a steady
state
What influences lines of
resistance?
• Past and present conditions of the individual
• Available energy resources (pain consumes
energy)
• Amount of energy required for adaptation
(remember Selye’s theory of adaptation)
• Patient’s perception of the stressor
Providing timely and effective pain
management to the injured patient can help
strengthen the patient’s lines of resistance
Neuman (continued)
If pain is allowed to be prolonged, the body’s
attempt to regain steady state may exhaust
the patient’s lines of resistance, leading to
disruption of the patient’s core structure—
death may result.
Future Pain
• Pain receptors in the periphery become more
sensitive after injury
• Permanent changes can occur in spinal cord
pathways after even a brief exposure to severe,
unrelieved acute pain
• Poorly controlled acute pain can predispose
patients to debilitating chronic pain syndromes
(McCaffery & Pasero, 1999).
• Chronic pain syndromes are often the result of
traumatic injury (Muse, 1986).
May lead to:
Chronic Pain Syndrome
• Pain becomes focus of life
• Relationships become altered
• Sometimes the result of acute, unrelieved
pain—such as multiple trauma, phantom
limb pain after amputation, repeated back
surgeries
• Sometimes stems from neuro-muscular
disorders such as fibromyalgia, rheumatoid
arthritis, multiple sclerosis
Chronic Pain
• Physicians and emergency departments may
cringe—very complex, time consuming, no
easy answers or quick fixes
• Behavioral medicine may be an approach—
learning different coping mechanisms,
biofeedback, non-opioid interventions
Treatment of Pain
• Historically, undertreated or untreated
• Not considered a priority
• Minimal knowledge base effective
interventions by healthcare providers
• Fear of addiction
• Fear of misdiagnosis
• Fear of weakness
Why have people continued to
suffer?
• The study of pain is relatively new
• Lack of knowledge concerning harmful effects of
unrelieved pain
• Personal biases
• Populations at high risk:
– Cognitively impaired
– Very young, very old
– Trauma, hemodynamically unstable
“he can’t even talk, he’s not in pain”
“what if we bottom out the B/P?”
“it’s not that important right now, wait
until surgery”
You—the patient
• Be knowledgeable
• Ask your physician/surgeon BEFORE your
•
•
•
•
surgery
If not satisfied, get second opinion
Take pain seriously
Take analgesics when you need them, don’t
save them for later
Avoid peaks and valleys
Pain
• Exacts a broad toll on the psyche in terms of
physical and emotional suffering (Hedderich & Ness,
1999)
We have the science, but are we
making any progress?
“Pain is a more terrible lord of mankind than
death itself.”
Albert Schweitzer
When the music changes, so must the
dance….
African Proverb