Presentation on theme: "Pain Assessment & Management"— Presentation transcript:
1Pain Assessment & Management M3 Palliative Medicine CurriculumSeema S. Limaye, MDUniversity of Chicago
2GOALSDescribe methods of pain assessment in cognitively impaired older adults.Understand various types of pain.Describe the basic pharmacology of opioidsUnderstand how to initiate and titrate opioids.
3Self-Directed Learning Modules Basics of Neuropathic painSide Effects of Opiods and Management OptionsTreatment of Pain in Persons with h/o Substance Abuse
4Mrs. P70 y.o. female h/o Paget’s disease, renal insufficiency, osteoporosis presents to clinic with new back pain.What do you want to obtain from the history?
5Pain HistoryPain Characteristics – onset, duration, location, quality, intensity, associated symptoms, exacerbating and relieving factorsPast and current management therapiesRelevant medical and family historyPsychosocial historyImpact of pain on daily life – work, daily activities, personal relationships, sleep, appetite, emotional statePatient (and family’s) expected goals for treatment
6Pain: A Complex Phenomenon Sensory stimuli and/or neurologic injury modified by an individual’s memory, expectations, emotionsBiocultural Model of Pain:Society also influences an individual’s pain experiences
7FIGURE 1. Normal sensory tracts FIGURE 1. Normal sensory tracts. The spinothalamic tract transmits input encoded for pain and temperature, and the dorsal column transmits input encoded for light touch. The free nerve ending of an A delta fiber or a C fiber senses pain and temperature and has its cell body in the dorsal root ganglion. This synapses in the dorsal horn with a second-order neuron that immediately crosses the midline and ascends on the contralateral side in the spinothalamic tract. The axons of the second-order neuron terminate in the hypothalamus and thalamus. In the thalamus, some projections are made directly to the primary sensory cortex, whereas others go to the limbic system, which includes the insula, amygdala, and cingulate cortex. The Pacinian corpuscle is a first-order neuron that senses pressure. This neuron’s cell body is also in the dorsal horn, and the axon ascends a few levels, crosses the midline, and ascends in the contralateral dorsal column/ medial lemniscus, through the medulla and midbrain, and terminates in the thalamus. There, the neuron synapses with a second-order neuron, which projects to the primary sensory cortex.
8Pain Assessment is NOT…. Relying on changes in vital signsDeciding a patient does not “look in pain”Knowing how much a procedure or disease “should hurt”Assuming a sleeping patient does not have painAssuming a patient will tell you they are in pain
9Consequences of Untreated Pain Acute pain:increase metabolic rate and blood clotting,impair immune functioninduce negative emotionsWithout intervention, pain receptors become sensitive and may have long lasting changes in the neurons
10Consequences of Untreated Pain Chronic pain may lead to:fatigue,anxiety,depression,confusion,increased falls,impaired sleep, anddecreased physical functioning/deconditioning
11Bedside Assessment ASK the patient about pain Asking about ADL’s and IADL’sAsking about physical activity, mood, sleep, appetite, energy levelIdentify preferred pain terminology-hurting, aching, stabbing, discomfort, sorenessUse a pain scale that works for the individual-Insure understanding of its use-Modify sensory deficitsFerrell et al. J Pain Symptom Manage Chinball and Tait Pain 2001.Herr and Garand. Pain Management in the Elderly 2001Ask the patient = even persons with moderate impairment (e.g. MMSE=12) can still reliably report pain with good test-retest reliability.Preferred pain terminology is very important as the word for “pain” varies from person to person. Some people think of “pain” to be different from an intense ache or hurt. At bedside we should ask a variety of these qualifiers “Are you aching? Hurting? Having discomfort?” to illicit the best response.Use a pain scale that works for that particular individual and remain consistent throughout subsequent interviews with the same patientUse: -simplest, clear explanation, give examples-give time to grasp task and respond-repetition KEYIt is important to use a pain scale whenever possible as it can help guide you in terms of treatment efficacy. Studies have shown that more than 80% of cognitively impaired persons are able to reliably complete a pain scale. The importance is in finding one that works for the individual. I will give you some examples in the next few slides. When describing the tool to a cognitively impaired individual you want to be patient and give simple and clear explanations, providing examples whenever possible. You need to give the patient time to process the information and formulate a response. You may have to repeat the instructions a few times before they get it. Keep in mind that these patients are often hard of hearing and have poor vision so you need to make sure they are wearing their glasses and hearing aids.High rate of completion of tools even with low MMSE (12)
12Use a standard scale to track the course of pain Pain Intensity ScalesSource: Acute Pain Management Guideline Panel. Acute Pain Management in Adults: Operative Procedures. Quick Reference Guide for Clinicians. Rockville, MD: US Department of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research. February AHCPR Pub. NoIn general, short simple verbal rating scales (e.g. no pain, slight pain, moderate, or severe pain) which focus on intensity are probably the easiest and most appropriate for use in those with acute pain. Studies have documented over a 70% completion rate. Numeric pain intensity scales as well as VAS have been found in the literature to be the more difficult scales to use in the elderly, regardless of cognitive status. Physiologic measures such as blood pressure and pulse are not reliable markers as they can vary depending on medications, comorbidities, or the normal aging process in general.
13Faces Pain Scale and Pain Thermometer At University of Chicago we use Wong_Baker Faces scale which is similar to the Faces Pain Scale. It was developed and validated in children. Visual scales may be more suitable for people with communication difficulties such as aphasia, illiteracy, or language barriers. The only caution would be that occasionally older adults mistake the Faces Pain Scale for a measure of depression or sadness rather than pain intensity.
14What are some common barriers to pain treatment?
15Remember the common patient-related barriers to pain management Drugs ..are addictingshould be saved for when it is really neededhave unpleasant or dangerous side effectspills are not as effective as a shotnarcotics are only for dying people
16Pain assessment in a vulnerable group: Cognitively Impaired Older Adults
17Assessing pain: Nonverbal, Moderate to Severe Impairment Formal assessment tools available but not necessarily useful in routine clinical settingsUnique Pain SignatureNonverbal Pain IndicatorsKaasalainen et al Perspectives Herr and Garand Clinics in Geriatric Medicine 2000
18Unique Pain Signature How does the patient usually act? What changes are seen when they are in pain?family membersnursing staffCommunication across caregiver settings is key!Kovach et al. J Pain Symptom Manage 1999.Feldt et al. JAGS 1998.Weiner et al. Aging 1998.
19Nonverbal Pain Indicators Facial expressions (grimacing)-Less obvious: slight frown, rapid blinking, sad/frightened, any distortionVocalizations (crying, moaning, groaning)-Less obvious: grunting, chanting, calling out, noisy breathing, asking for helpBody movements (guarding)-Less obvious: rigid, tense posture, fidgeting, pacing, rocking, limping, resistance to movingKaasalainen et al Perspectives Herr and Garand Clinics in Geriatric Medicine 2000
20Selection of pain meds Source/type of pain Duration/timing/frequency History of medication useImpact on quality of lifePresence of associated factors
21Types of Pain: A Brief Review Nociceptive PainVisceralSomaticNeuropathic PainMixed/Unspecified PainPsychologic cause
23Quality: Somatic pain Descriptors: aching, deep, dull, gnawing Distribution/Examples:Well localized—patients can often point with one finger to the location of their painbone mets, strained ankle, toothacheAnalgesics: NSAIDS, acetaminophen opioids
24General Principles of Management Set a goal of reduction of pain to tolerable levels, not a goal of complete relief“Start low and go slow”Make sure patient and family are aware of goalsFrequent clinic visits at first for assurance, validation, and monitoring of titration
25WHO 3-Step ladderSource: World Health Organization. Technical Report Series No. 804, Figure 2. Geneva: World Health Organization; Reprinted with permission.
27Non-opioid medications Acetominophen 650mg tid-qid : concern for hepatic toxicity >3-4gramsNSAIDs including Ibuprofen, Naproxen, COX-2 inhibitors: concern for gastric / renal toxicity, platelet dysfunction, may inhibit anti-hypertensive meds
28Opioid combination products The following opioids are available as combination products with acetaminophen, aspirin, or ibuprofenCodeine; hydrocodone; oxycodone; propoxypheneTypically used forModerate episodic (PRN) painBreakthrough pain in addition to a long-acting opioid.Never prescribe more than one combination drug at any one time.
29Which combination product? Analgesic potency:hydrocodone and oxycodone are more potent than codeine, which is more potent than propoxyphene, which some studies suggest is equipotent to aspirin.there is little difference between hydrocodone products and oxycodone products in terms of potency.Note: propoxyphene products are not recommended for pain in most national pain guidelines, due to side effects and unclear efficacy compared to other products
34ReceptorClinical EffectsKappa 1Spinal analgesiaMiosisDiresisKappa 2PsychotomimesisDysphoriaKappa 3Supraspinal analgesiaDeltaSpinal and supraspinal analgesiaNociceptin/orphaninAnxiolysisAnalgesia
35Clearance concerns Conjugated by liver 90%–95% excreted in urine Dehydration, renal failure, severe hepatic failure dosing interval (extend time) or dosage sizeif oliguria or anuriaSTOP routine dosing of morphineuse ONLY prn
36Opiod Pharmacology… What is the peak effect (C max ) of morphine: PO?30-60 minIV?5-15 minSC/IM?Variable…usually minWhat is the duration of effect of morphine?3-4 hoursUsually 1-2 hours, but we typically dose it q2-3 hours
37Cmax Half-life (t1/2) IV SC / IM Plasma Concentration po / pr Time This picture demontrates that for most opiates that are considered short-acting (MSIR, Oxycodone, Hydrocodone, dilaudid) the half-life is about the same no matter the route of administration. What does differ is the Cmax or the time it takes to reach maximal concentration. Once the drug has reached Cmax there will not be any additional analgesia. This becomes important when we discuss the appropriate time to give a “breakthrough dose”.EPEC, reprinted with permissionHalf-life (t1/2)Time
38. . . More Opioid Pharmacology Steady state after 4–5 half-livessteady state after 1 day (24 hours)Side Effects:sedation, confusion, respiratory depression, constipation, urinary retention, nausea and vomiting
39Short Acting Opioids Oral only Parenteral or Oral oxycodone (Percocet ® , Tylox ® )hydrocodone (Vicodin ® Lortab ®, Lorcet ®)propoxyphene (Darvon ®, Wygesic ®)Note: hydrocodone is only available as a combination product.Parenteral or Oralmorphinehydromorphone (Dilaudid ®)meperidine (Demerol ®)codeine
40Routine oral dosing extended-release preparations Improve compliance, adherenceDose q 8, 12, or 24 h (product specific)don’t crush or chew tabletsmay flush time-release granules down feeding tubesAdjust dose q 2–4 days (once steady state reached)
41Transdermal Fentanyl Duration 24-72 hours 12-24 hours to reach full analgesic effectNot recommended as first-line in opiate naïve patientsLipophilicSimple Conversion rule:-1 mg po morphine = ½ mcg fentanyl-(60 mg morphine roughly 25 mcg patch)
43ADDING AN OPIOID To achieve quick pain relief: (LOAD) 1. Start low dose, short-acting2. Dose q peak3. Re-eval in 4 hrs. to figure out what dose is needed
44Breakthrough dosing Use immediate-release opioids 10% of 24-h dose (or 1/3 of one ER dose)offer after Cmax reachedpo / pr q 1 hSC, IM q 30 minIV q 10–15 minDo NOT use extended-release opioids for breakthrough
45Ongoing assessmentIncrease analgesics until pain relieved or adverse effects unacceptableBe prepared for sudden changes in painplan for breakthroughs (prior to dressing changes or patient care activities)
46Opioid Dose Escalation Always increase by a percentage of the present dose based upon patient’s pain rating and current assessment50-100% increaseSevere pain7-10/1025-50% increaseModerate pain4-6/1025% increaseMild pain1-3/10
47Incomplete cross-tolerance If a switch is being made from one opioid to another it is recommended to start the new opioid at ~50% of the equianalgesic dose.This is because the tolerance a patient has towards one opioid, may not completely transfer (“incomplete cross-tolerance”) to the new opioid.to50%of new Opioidfrom100%
48Pain Problem #1You started Mrs. T on 10 mg morphine every 4hrs around the clock for her cancer pain with good effect. She says she’s tired of taking a pill every 4 hours. Convert her to long-acting morphine with appropriate prn doses.
49Pain Problem #1: Answer 24 hour use: 10mg PO morphine x 6 = 60 mg PO morphineConvert to long-acting twice a day dosing:60 mg PO morphine / 2 = 30mg PO morphine SR BIDCalculate prn dosing of morphine sulfate-immediate release:60mg PO morphine in 24 h x 10% = 6mg PO morphine q3h prn breakthrough pain
50Part 2She is admitted to the hospital and unable to take oral medications--convert Mrs. T to: IV morphine
51Part 2: Answer Ratio of IV:PO morphine sulfate: 1mg:3mg Therefore: 60/x = 3/1X=20mg IV morphine in 24hr periodDose q 3h = 20mg/8 = 2.5mg IV q3hrPRN dose?2mg IV morphine q 2hr prn breakthrough pain
52Part 3Mrs. T has uncontrolled pain of moderate intensity because of progression of her disease. How would you re-dose her IV morphine?
53Part 3-AnswerIncrease pain regimen by 25-50% for moderate uncontrolled painLet’s increase by 25%25% of 20mg IV morphine = 25mg IV morphine in 24 hoursDosing q3h= 25mg/8 = 3mg IV morphine q3h
54Pain Problem #2Mr. T is a 73 yo man with lung cancer, a malignant plueral effusion, and chronic chest pain. He has undergone therapuetic thoracentesis and pleuradesis. He is currently receiving meperidine 75 mg IM q6h, for pain. You want to switch him to oral morphine because you are aware that:1. IM meds hurt!2. it’s metabolite, normeperidine, can accumulate in pts (with renal failure) and cause CNS toxicity such as tremulousness, dyphoria, myoclonus and sz.Without adjusting for incomplete cross-tolerance, what dose and schedule would you choose?
55Pain Problem #2: Answer Ratio of IV meperidine: PO morphine 50mg:15mg 75mg x 4 = 300mg300/x = 50/15X=90 mg PO morphine in 24hAdjust for incomplete cross-tolerance:Decrease by 1/3 = 60mgDosing PO morphine q4h:10mg PO morphine q4h