pain management -03-07 version

8/14/2019 Pain Management -03-07 Version

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By: Mayla Lerias Saba, R.N., M.D.


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A look at pain

Pain is a complex, subjective phenomenon thatinvolves biological, psychological, cultural,

and social factors to put it succinctly, pain iswhatever the patient says it is, and it occurswhenever she says it does. The only trueauthority on any given pain is the person

experiencing it.


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Pain thresholds and tolerances vary. Painthreshold is a physiologic attribute that

denotes the intensity of the stimulus neededto sense pain. Pain tolerance is apsychological attribute that describes theamount of stimulus ( duration and intensity)that the patient can endure before statingthat shes in pain.

Theories about pain

SpecificityPattern

Gate control


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Lets get specificThe specificity theory maintains that

individual specialized peripheral nerve fibersare responsible for pain transmission. Thisbiologically oriented theory doesnt explainpain tolerance, nor does it allow for social,

cultural, or empirical factors that influencepain.


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Opening the gateThe gate control theory asserts that

some sort of gate mechanism in the spinalcord allows nerve fibers to receive painsensations. (See Understanding the gatecontrol theory.) This theory has encourage a

more holistic approach to pain managementand research by talking into account the nobiological components of pain. Painmanagement techniques, such as cutaneous

stimulation, distraction, and acupuncture are,in part, based on this theory.


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Types of painThere are two fundamental pain types acute and chronic.

Acute Pain

Acute pain commonly accompanies tissue damagefrom injury or disease. It varies from mild to serve in intensityand typically lasts for a brief period (less than 6 months). Acutepain is considered a protective mechanism, alerting theindividual to tissue damage or organ disease as the underlyingdisorder heals.

Relief and healingTreatment goals for acute pain include relieving pain andhealing the underlying injury or disease responsible for thepain. Palliative treatment may include surgery, drug therapy,application of heat or cold, or psychological and behavioraltechniques to control pain.


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Understanding the gate control

theory

Intensive research into the pathophysiology ofpain has yielded several theories about painperception, including the MelzackWall gatecontrol theory. According to this theory, painand thermal impulses travel along small-

diameter, slow-conducting afferent nervefibers to the spinal cords dorsal horns. There,they terminate in an area of gray mattercalled the substantia gelatinosa.


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Open or close the gate

When sensory stimulation reaches a criticallevel, a theoretical gate in the substantiagelatinosa opens, allowing nearbytransmission cells to send the pain impulse tothe brain along the interspinal neurons to thespinothalamic tract, and then to the thamalusand cerebral cortex (see illustration below,left). The small sizes of the fibers enhancespain transmission. In contrast, large-diameter

fibers inhibit pain transmission Stimulation ofthese large, fast-conducting afferent nervefibers counters the input of the smaller fibers,thereby closing the theoretical gate in thesubstantia gelatinosa and blocking the paintransmission (see illustration below, rigth).


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Keys to the gate

Descending (efferent) impulses along

various tracts from the brain andbrain stem can enhance or reducepain transmission at the gate. Forexample, triggering specific brainprocesses, such as attention,emotions, and memory of pain, canintensity pain by opening the gate.


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Chronic pain

The cause or chronic pain isnt always clear.Chronic pain can stem from prolonged diseaseor dysfunction, as in cancer and arthritis, or itcan be associated with a mental disorder such

as posttraumatic stress syndrome. It can beintermittent, limited, or persistent and usually6 months or longer. This type of pain isstrongly influenced by the patient emotions

and environment.


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There are three categories of chronic pain:

1 chronic nonmalignant pain, such as the painassociated with nonprogressive or healed

tissue injury2 chronic malignant pain, such as the painassociated with cancer or other progressivedisorder

3 chronic intractable pain, such as the pain thatincreases as the patient ability to copedeteriorates


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Not the pain next door

Chronic pain isnt always localized whichmakes difficult at times for the patientto clearly describe what he feeling.Furthermore, a patient with chronic painreacts in different ways, making itdifficult for the health care professionalsto assess the pain. One patient may cry

out, one may groan and still anothermay simply withdraw. Changes inappetite, sleeping patty can be

important clues into the nature of the


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Have a stable day

Treat for chronic pain focuses on reducing oreliminating the patient pain whileimproving, or at least stabilizing, his ability

to conduct daily activities. It also attemptsto reduce the patient need for medication.In mild chronic pain Treatment mightsimply involve ice massage and exercise.

However, severe chronic pain typicallyrequires a multidisciplinary program toaddress the physiological, psychological,and social component of the patientscondition


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Assessing pain

The only way to get an accurate understanding ofthe patients pain is to ask him. Begin by asking

the patients to describe his pain Where does ithurt? What exactly does it feel like? When does itstart, how long does it last, and how often does itrecur? What provokes it? What makes it feel

better? There are a variety of assessment toolsthat can help. Encourage the patient to use oneto obtain a more accurate and consistentdescription of pain intensity and relief two

important measurements.


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Where does it hurt

Find out how the patient responds to pain. Doeshis pain interfere with eating? Sleeping?Working? His sex life? His relationship? Askthe patient to point to the area where he feelspain, keeping in mind That

Localized pain is felt only at its originProjected pain travel along the nerve pathways

Radiated pain extend in several direction fromthe site of origin.

Referred pain occurs in places remote from thesite of origin.


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Natures Source

Factors that influence the nature of patients paininclude duration, severity and source. The source

may be:Cutaneous, originating in the skin or subcutaneous

tissue

Deep somatic, which include nerve, bone, muscle, and

supporting tissueVisceral, which include the body organs. Watch for

physiological responses to pain (nausea, Vomitingchanges in vital signs) and behavioral responses to

pain (facial expression, movement and positioning,what the patient say or doesnt say). Also notepsychological responses, such as anger, depression,and irritability.


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About attitude

Assess the patients attitude about pain. Askhim how he usually handles pain. Does he tellother when he hurt, or does he try to hide it?Does his family understand his pain and try tohelp him deal with it? Does he accept theirhelp?


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Pain Assessment tools

Several easy-to-use tools can help you betterunderstand the patients pain.

A rating scale is a quick method of determiningthe patients perception of pain intensity. Askhim to rate his pain on a scale from 1 to 10. With1 representing pain-free and 10 representing the

most pain imaginable.


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A face rating scale uses illustrations of five ormore faces with expressions that range fromhappy to very unhappy. The patient choosesthe face that represents how he feels at the

moment. It's particularly useful with a youngchild or a patient with language difficulty.


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A body diagram allows the patient to draw thelocation and radiation of pain on an illustrationof the body

A questionnaire provides the patient with keyquestion about the pains location, intensity,quality, onset, and aggravate pain.


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A questionnaire provides the patient with keyquestion about the pains location, intensity,quality, onset, and aggravate pain.


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Managing pain

Pain management can involve drug therapywith opioid or nonopioid analgesic, includingpatient controlled analgesic (PCA) and

adjuvant analgesic, neurosurgery;transcutaneous electrical nerve stimulation(TENS) and cognitive behavioral strategies


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Opioid analgesics

Opioid analgesics are prescribed to relievemoderate to serve pain They include opiates

and opioid. Opiates are natural opiumalkaloids and their derivatives, opioid aresynthetic compound but can also includeopiates. Morphine is the prototype for both

types of opioid analgesic


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The agony and the

ecstasyOpioid analgesics are classified as agonists oragonists-antagonists. Agonists are drugs thatproduce analgesia by binding to central nervoussystem (CNS) opiate receptors. These drugs are

the drugs of choice for severe chronic pain. Theyinclude:

CodeineHydromorphone

LevorphanolMeperidineMethadoneMorphine

Propoxyphene


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Up the antiAgonists-antagonists also produce analgesia by

binding to CNS receptors. However, theyre oflimited use for patients with chronic pain becausemany have a ceiling effect or upper dosing limit.As the dosage increases, they also can causehallucinations and other psychotomimetic effects

and, in opioid-dependent patients, can producewithdrawal symptoms. This class of drugsincludes:

Buprenorphine

Butorphanol

Nalbuphine

Pentazocine


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Caution is the key

Opioids can produce severe adverse effects;therefore, caution is the key. Theyrecontraindicated in patients with severerespiratory depression and should be usedcautiously in patients with:

Chronic obstructive pulmonary disease

Hepatic or renal impairment, because theyremetabolized by the liver and excreted by the

kidneysHead injuries or any conditions that raises

intracranial pressure (ICP) because theyincrease ICP and can induce miosis (which can

mask pupil dilation, an indicator of increased


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Monitoring

Before giving an opioid analgesic, make sure thepatient isnt already taking a CNS depressant suchas barbiturate. Concurrent use of another CNS

depressant enhances drowsiness, sedation, anddisorientation.

During administration, check the patients vitalsigns and watch for respiratory depression. If his

respiratory rate declines to 10 breaths/minute orless, call his name, touch him, and tell him tobreathe deeply. If he cant be aroused of if hesconfused or restless, notify the doctor andprepare to administer oxygen. If ordered,administer an opioid antagonist such as naloxone.


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Understanding patient-controlled analgesia

A patient controlled analgesia (PCA) system

provides optimal opioid dosing whilemaintaining a constant serum concentrationof the drug.

How it works?

A PCA system consists of a syringe injectionpump piggybacked into an I.V. orsubcutaneous infusion port. When the patientpresses a button, he receives a preset bolus

dose of medication. The doctor programs thebolus dose and the lock-out time betweenboluses, thus preventing overdose. The deviceautomatically records the number of times thepatient presses the button, helping the doctor

adjust the dosage.


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In some cases, the PCA system allows a

reduction in drug dosage, possibly becausethe patient feels more control over his painrelief and knows that, if hes in pain, analgesiais quickly available. This tends to reduce thepatients level of stress and anxiety which canexacerbate pain.


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Patient teachingTeach the patient About his drug therapy and ways to avoid or

resolve adverse effects. Tell him to:

Take the prescribed drug before the pain becomes intenseto maximize its effectiveness and talk with the doctor if thedrug seems less effective over time.

Not increase the dose or frequency of administration andtake a missed dose as soon as he remembers, while

maintaining the interval between doses. Skip the missed dose if its just about time for the next dose

to avoid serious complications of double dose. Refrain from drinking alcohol while taking the drug to avoid

pronounced CNS depression.Talk with his doctor if he decides to stop taking the drug

because the doctor can suggest an appropriate gradualdosage reduction to avoid withdrawal symptoms.

Avoid postural hypotension by getting up slowly whengetting out of bed or a chair.

Eat a high-fiber diet, drink plenty of fluids, and takes a stoolsoftener, if prescribed.


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Nonopioid analgesicsNonopioid analgesics are prescribed to manage

mild to moderate pain. When used with anopioid analgesic, they help relieve moderateto severe pain and also allow lower dosing ofthe opioid agent. These drugs include

acetaminophen and NSAIDs, such as aspirin,ibuprofen, indomethacin, naproxen, naproxensodium, phenylbutazon, and sulindac.


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Special effects NSAIDs and acetaminophenproduce antipyretic and analgesic effects. In

addition, as their name suggest, NSAIDs havean anti inflammatory effect. Because thesedrugs all differ in chemical structure, theyvary in their onset of action, duration or

effect, and method of metabolism andexcretion.

In most cases, the analgesic regimen includes

a nonopiod drug even if the patients pain issevere enough to warrant treatment with anopiod. Theyre commonly used to treatpostoperative and postpartum pain,headache, myalgia, arthralgia,

dysmenorrheal, and cancer pain.


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Not so special effects

The chief adverse effects of NSAIDs include:

inhibited platelet aggregation (rebounds whendrug is stopped)

GI irritation

Hepatotoxicity

Nephrotoxicity

Headache

Liver damage (in long-term, high-dose use).


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NSAIDs shouldnt be used in patients withaspirin sensitivity, especially those withallergies, asthma, and aspirin-induced nasalpolyps, due to the increased risk of

bronchoconstriction or anaphylaxis. Also,NSAIDs are contraindicated in patients withthrombocytiopenia, and should be usedcautiously in neutropenic patients because

antipyretic activity may mask the only sign ofinfection. Some NSAIDs are contraindicated inpatients with renal dysfunction, hypertension,GI inflammation, or ulcers.


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Before administering nonopioid analgesics, checkthe patients history for a previoushypersensitivity reaction, which may indicatehypersensitivity to a related drug in this group. If

the patient is already talking an NSAID, ask him ifhe has experienced GI irritation. If he has, thedoctor may choose to reduce the dosage ordiscontinue the drug.

If the patient is undergoing long-term therapy,report any abnormalities in renal and liverfunction studies. Also, monitor hematologicstudies and evaluate complaints of nausea orgastric burning. Watch for sign or iron deficiency

anemia, such as pallor unusual fatigue, and


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For patient talking and NSAID, teach him thesigns and symptoms of overdose,hypersensitivity, and GI bleeding, such asrash, dyspnea, confusion, blurred vision,

nausea, bloody vomitus, and black, tarrystools. Tell him to report any of these signs tohis doctor immediately.

If the patient is talking acetaminophen, teachhim that nausea, vomiting, abdominal cramps,or diarrhea may indicate an overdose and thathe should notify his doctor immediately.

Patient teaching


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Neurosurgery

Neurosurgery is an extreme form of painmanagement and is rarely needed. However ,there are a number of procedures, such asrhizotomy and cordotomy, that can controlpain by surgically modifying critical points inthe nervous system. (see surgical interventionfor pain,)


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Surgical intervention for pain

Surgery is typically considered to manage painonly when pharmacologic therapies fail. Moreand more however, these techniques arebeing used earlier with excellent effect.Surgical procedures used to treat pain includeneurectomy, rhizotomy, cordotomy,cryoanalgesia, and radio frequency lesioning.


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Neurectomy involves resection or partial ortotal excision of a spinal or cranial nerve. Thisprocedure is relatively quick and only requireslocal or regional anesthesia. Unfortunately.

Loss of motor sensation is a possible adverseeffect, and pain relief may only be temporary,peripheral neurectomy is consider when allstandard pain management therapies have

failed.


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Rhizotomy involves cutting a nerve to reliefpain. Rhizotomy of the dorsal nerve root mayproduced analgesia for localized severe pain,such as on the trunk, abdomen, or limb. Motor

function is usually unaffected if one dorsalnerve root for the area is left intact.


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Cordotomy can be performed as an opensurgery or percutaneously. A unilateralcordotomy is performed to relieve somaticpain on one side of the body. A bilateral

cordotomy is performed to relieve visceralpain on both sides of the body.


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Cryoanalgesia deactivates a nerve using acooled probe that cause temporary nerveinjury. Nerve function returns over time andthe procedure can be repeated. Cryoanalgesia

can provide pain relief for the patient withpain from a surgical scar, a neuroma trappedin scar tissue, and occipital neuralgia.


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Radio-frequency lesioning

Radio-frequency lesioning may affect the nervefrom heat generated, the magnetic fieldcreated by the radio waves, or both nerve

function is stopped for a prolonged period. If itdoes return, the procedure can be repeated.The most frequent use of this technology is toretreat pain related to the facet joint andlumbar sympathetic and peripheral nerves.Because its a focused therapy. Its used whenspecific nerves can be targeted.


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Tens

Tens relieves acute and chronic painby using a mild electrical current

that stimulates nerve fibers to blockthe transmission of pain impulses tothe brain. The current is delivered

through electrodes placed on theskin at points determined to berelated to the pain. TENS is used to

treat:


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Chronic back pain

Postoperative pain

Dental pain Labor pain

Pain from peripheral neuropathy or nerve injury

Postherpetic neuralgia

Reflex sympathetic dystrophyMusculoskeletal trauma

Arthritis

Phantom limb pain.


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TENS is contraindicated if the patient has apacemaker. The current may also interferewith electrocardiography or cardiacmonitoring. Furthermore, TENS shouldnt beused when the etiology of the pain is unknownbecause it might mask a new pathology.


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Asses the patient for signs of excessive or

inadequate stimulation. Muscle twitching mayindicate overstimulation, whereas an inabilityto feel any tingling sensation may mean thatthe current is too low. If the patient complaints

of pain or intolerable paresthesia, check thesettings, connections, and electrodeplacements. Adjust the settings if necessesary.If you must relocate the electrodes during

treatment, first turn off the TENS unit. Evaluatethe patients response to each TENS treatmentand compare the results. Also, use yourbaseline assessment evaluate theeffectiveness of the procedure.


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If the patient will use the TENS unit at home,have him demonstrate the procedure,including electrode placement, the settings ofthe units control, electrode removal, and

proper care of the equipment. Explain that heshould strictly follow the prescribed settingsand electrode placement.

Warm against using high voltage, which can

increase pain, or using the unit to treat painfor which he doesnt know the cause. Also tellthe patient to notify the doctor if pain worsensor develops at another site.


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Behavior modification and relaxationtechniques may be used to help the patientreduce the suffering associated with pain.

These techniques included biofeedback,

distraction. Guided imagery, hypnosis, andmeditation. These mind-over-paintechniques allow the patient to exercise adegree of control over his pain. In addition,

they have the added benefit of being virtuallyrisk-free with few contraindications. Even so, ifthe patient has a significant psychiatricproblem, a psychotherapist should teach him

the relaxation techniques


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pain management -03-07 version

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