Taylor Fundamentals of Nursing Chapter 34: Comfort + Pain Management

Nociception

The ability to feel painful stimuli

4 Physiologic Processes Involved in Nociception

1.) TRANSDUCTION: The activation of pain receptors. Nociceptors (peripheral receptors) respond SELECTIVELY to specific noxious stimuli.

2.) TRANSMISSION OF PAINFUL STIMULI: Pain sensations from the site of an injury of inflammation are conducted along pathways to the spinal cord + then onto higher centers. This overall process is called TRANSMISSION. No specific pain organs or cells exist in the body. Rather, an interlacing network of undifferentiated free nerve endings receives painful stimuli. Larger A-fibers transmit acute, well-localized pain; the smaller C-fibers convey diffuse, visceral pain that is often described as burning + aching.

3.) PERCEPTION OF PAIN: Involves the sensory process that occurs when a stimulus for pain is present. It includes the persons' interpretation of pain. The PAIN THRESHOLD is the LOWEST intensity of a stimulus that causes the subject to recognize pain.

4.) MODULATION OF PAIN: The process by which the sensation of pain is inhibited or modified is MODULATION. The sensation of pain appears to be regulated or modified by NEUROMODULATORS, which are endogenous opioid compounds in the brain + spinal cord. They have analgesic activity that alters the perception of pain. These include: ENDORPHINS (with the type called DYNORPHIN having the most potent effect) + ENKEPHALINS (thought to reduce pain by inhibiting the release of substance P from the terminals of afferent neurons).

Bradykinin

A powerful vasodilator that increases capillary permeability + constricts smooth muscle, plays an important role in the chemistry of pain at the site of an injury even before the pain message gets to the brain.

- Triggers the release of HISTAMINE + produces the redness, swelling + pain typically observed when inflammation is present

Prostaglandins

Hormone-like substances that send additional pain stimuli to the CNS

Substance P

Sensitizes receptors on nerves to feel pain + also increases the rate of firing of nerves

Pain Threshold

The LOWEST intensity of a stimulus that causes the subject to recognize pain.

Gate Control Theory of Pain

- SMALL diameter nerve fibers conduct excitatory pain stimuli TOWARD the brain.

- LARGE diameter nerve fibers appear to INHIBIT the transmission of pain impulses to the brain.

- There is a gating mechanism that is believed by some to be located in the SUBSTANTIA GELATINOSA cells int eh dorsal horn of the spinal cord. The exciting + inhibiting signals at the gate in the spinal cord determine the impulses that eventually reach the brain. Thus, only a limited amount of sensory information can be processed by the nervous system at any given moment. When too much information is sent though, certain cells in the spinal column interrupt the signal as if closing the gate.

- The brain can also influence the gating mechanisms. Past experiences + learned behaviors are interpreted by the brain + can regulate or adjust the eventual behavioral responses to the brain.

Acute Pain

- Generally rapid in onset + varies in intensity from mild to sever

- Protective in nature

- Warns the person of tissue damage or organic disease

- After its underlying cause is resolvd, acute pain disappears

Chronic Pain

- Pain that is limited, intermittent or persistant but that lasts beyond the normal healing period.

- People commonly experience periods of REMISSION or EXACERBATION

- Pain associated with cancer or other progressive disorders is termed chronic MALIGNANT pain

- Pain in people whose tissue injury is non-progressive or healed is termed chronic NONMALIGNANT pain

-

Cutaneous Pain

- Superficial pain

- Usually involves the skin or subcutaneous tissue

Somatic Pain

- Deep pain

- Diffuse or scattered + originates in tendons, ligaments, bones, blood vessels + nerves.

Visceral Pain

- Poorly localized + originates in body organs in the thorax, cranium + abdomen

- Occurs as organs stretch abnormally + become distended, ischemic or inflamed

- A person automatically tenses the abdomen when an acute abdominal pain condition is present.

Referred Pain

Pain that originates in one part of the body but is perceived in an area distant from its point of origin.

Nociceptive Pain

The normal process that results in noxious stimuli being perceived as painful.

Nociceptors

Peripheral nerve fibers that transmit pain from somatic + visceral sites.

Neuropathic Pain

Results as a direct consequence of a lesion or disease affecting abnormal functioning of the PNS or CNS.

- The cause is unknown but it can originate either peripherally (ex. phantom leg pain) or centrally (ex. pain from spinal cord injury).

- Can be short induration but frequently is chronic.

- Often described as burning, electric, tingling or stabbing

- Commonly characterised by allodynia

Allodynia

- A characteristic feature of neuropathic pain

- Pain that occurs after a weak or nonpainful stimuli such as a light touch or a cold drink.

Intractable

When pain is resistant to therapy + persists despite a variety of interventions.

Phantom Pain

Pain that is often referred to an amputated leg where receptors + nerves are clearly absent

Psychogenic Pain

Pain in which a physical cause cannot be identified.

Ethnocentrism

The tendency to believe that one's cultural norms are correct + are the standard used to evaluate other's pain.

Pain Tolerance

The point beyond which a person is no longer willing to endure pain.

9 Therapeutic Effects of Laughter

1.) Decreases levels of epinephrine (the stress hormone)

2.) Activates the immune system

3.) Elevates the threshold for pain + can minimize the pain sensation

4.) Promotes spiritual + psychological coping

5.) Helps one to face difficult or unpleasant procedures

6.) Creates a more positive atmosphere

7.) Increases heart rate + stimulates circulation

8.) Deepens respirations

9.) Causes muscles to contract

Analgesic

A pharmaceutical agent that relieves pain

Breakthrough Pain (BTP)

- Is a temporary flare up of moderate to severe pain that occurs even when the patient is taking ATC medication for persistent pain

- As many as 50 - 90% of cancer patients experience breakthrough pain