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 #1Cousins’ 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 ventilationfunctional 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