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https://youtu.be/mnAehjF7p3E

Frontiers in Pain Management@

Iowa Physician Assistant Society

Thomas Benzoni, DODes Moines, IAApril 16, 2019

Objectives; a road map

• Where we are• How we got here• Where we’re headed• Alternate destinations

Declarations

• Agency• None

• Conflict of interest• None

• FDA statement• Likely off-label remarks

• Rules of engagement• Adult conversation

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Objectives

• Define pain.• High level review of pain mechanisms.• Control pain though at least 3 means.• Know what to do when the situations goes south.• Avoid giving your patients more than they came in with.• Have a plan.

• I will cover doses superficially; you can look those up. • (Raise your hand if you want to cover deeper today.)

• Anatomy is not intended to be an anatomy class.

How we’ll do this

• Decisions:• Blocks

• Regional (U/S guided)

• Local (nerve block)

• Field (wound infiltration)

• Systemic treatment• Opioids, NSAIDS

• Sedation, medical v vocal

• Toxicity• Medical consequences• Social consequences

• Pain terminology• Definition: What is pain?• Origins: Where does it come from?

• Interpretation: What does it mean?

• Anatomy and physiology of pain• Local receptors

• Ion channels

• Nerve pathways:• Peripheral

• Spinal

• Supratentorial

What is pain?

• (Broadly, it’s best to define the topic.)• The question is essentially existential yet unavoidable.

• Primary complaint >50% ED visits• Lesional pain: diagnosable cause with pain a likely component• Non-lesional* pain is likely present more frequently than diagnosed

• Non-lesional = no objective physical cause

• Definition for today• “…localized physical suffering associated with bodily disorder…”

• Merriam Webster

(There is a second: “.. acute mental or emotional distress or suffering…”)

Is all pain the same?

•Yes.

•In the end, all pain is an interpretation by the brain.

•This is a crucial concept.

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Pain pathways

• Skin/organ nocioceptor stimulated• Afferent fiber to dorsal root ganglion• Enter dorsal horn• Some processing occurs here…

• Ascend spinothalamic tract• Thalamus projects to higher centers• Interpretation mandatory on cortex• Action/reaction

• *Multiple opportunities to interrupt. http://thebrain.mcgill.ca/flash/a/a_03/a_03_cr/a_03_cr_que/a_03_cr_que_1a.jpg http://encyclopedia.lubopitko-

bg.com/images/Sensory%20receptors%20in%20human%20skin.jpg

https://www.ausmed.com/articles/wp-content/uploads/2015/04/20150422-image1.jpg

Mechanism of local anesthetics

• Lidocaine is representative• Blocks voltage-gated sodium ion channels.• Nerve can’t depolarize.• If no signal, there is no pain.• Answers “a tree falls in the woods”

• Amides v esters• Esters more allergenic (procaine)

• Onset, pain of infiltration, duration of actionhttp://img.tfd.com/elsevier/thumbs/u14-01-9780443102158.jpg

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Local anesthetics

Drug Brand Composition Toxic dose (mg/kg) Duration (h)*

Procaine Novocaine Ester 7 0.25 – 0.75

Lidocaine Xylocaine Amide 4.5 1 – 2

Bupivacaine Marcaine Amide 2 4 – 8

Onset 2 – 4 min (all) *X2 w/ epinephrine

Adapted from Laceration Management, Hollander and Singer, AEM, Sept. 1999

*Note: You must know common toxicities and treatment of any drug you use.

Reducing the pain of infiltration

• Warm to body temp• Carry in pocket, keep in warmer

• Raise pH• NaHCO3 – 1 ml/10 ml anesthetic

• Slow infiltration• Gradual tissue distention

• Go through wound edge• Sensory nerves already cut

• Irrigate with anesthetic• Topical effect

• Administer EMLA• Occlusive dressing

• Small gauge needle• 27 g fine

• Stimulate proximally• Spinal cord gating

https://www.ausmed.com/articles/wp-content/uploads/2015/04/20150422-image1.jpg

Local Intervention points Where can local anesthetics be used?

• Field• Around wound edges

• Ring• Digital nerves

• Flexor sheath• Regional• Distribution

• Spinal• Epidural or intrathecal

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Systemic pain control

• NSAIDS • Opioids

https://s-media-cache-ak0.pinimg.com/originals/cd/ad/df/cdaddf14e6a3b456ab6d386f10863ec0.png

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams• Propionic acids• Salicylates

• Opioids

https://www.ausmed.com/articles/wp-content/uploads/2015/04/20150422-image1.jpg

NSAID Intervention points Systemic pain control

• NSAIDS• Acetic acids

• Diclofenac• Etodolac• Indomethacin• Ketorolac• Nabumetone• Sulindac• Tolmetin

• Opioids

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Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors

• Celocoxib

• Opioids

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates

• Meclofenamate• Mefenamic acid

• Opioids

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams

• Meloxicam• Piroxicam

• Opioids

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams• Propionic acids

• Fenoprofen• Flurbiprofen• Ibuprofen• Ketoprofen• Naproxen• Oxaprozin

• Opioids

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Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams• Propionic acids• Salicylates

• Aspirin• Diflunisal• Magnesium salicylate• Salsalate

• Opioids

Systemic pain control

• NSAIDS• Side effects/toxicity:

• Renal insufficiency• GI bleeds• Hypertension

• More

• Opioids

Systemic pain control

• NSAIDS • Opioids

https://s-media-cache-ak0.pinimg.com/originals/cd/ad/df/cdaddf14e6a3b456ab6d386f10863ec0.png

Points of interest

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams• Propionic acids• Salicylates

• Acetaminophen: in a class by itself

• Opioids

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Systemic pain control

• NSAIDS

• Acetaminophen• COX 2 inhibition

• Lowers fever (hypothalamic)• Pain (serotonin)

• Endocannabinoid activity• NDMA receptor block• No thromboxane (platelet) action• Not very good for back pain• Useful in emotional pain

• Opioids

Systemic pain control

• NSAIDS• Acetaminophen• Toxicity

• Liver damage• Watch combo drugs!

• Opioids

Systemic pain control

• NSAIDS• Acetic acids• COX-2 inhibitors• Fenamates• Oxicams• Propionic acids• Salicylates

• AcetaminophenLearn 1 in each class. Get good at that one. Change logically!

• Opioids

Systemic pain control

• NSAIDS • Opioids

http://www.pharmacytimes.com/publications/issue/2011/june2011/an-overview-of-opioids

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https://www.ausmed.com/articles/wp-content/uploads/2015/04/20150422-image1.jpg

Opioid Intervention points

Systemic pain control

• NSAIDS • Opioids• Endogenous• Opium alkaloids• Semisynthetic opioids• Synthetic opioids

• Chemical:• Phenanthrenes• Phenylheptylamines• Phenylpiperidines

• (We’ll not use this schema….)

Not valid for methadone! Do not use equivalence for dosing; start lower.

Systemic pain control

• NSAIDS • Opioids• Endogenous

• Endorphins• Enkephalins• Dynorphins

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Systemic pain control

• NSAIDS • Opioids• Endogenous• Opium alkaloids

• Morphine• Codeine

• Tramadol is codeine pro-drug

Systemic pain control

• NSAIDS • Opioids• Endogenous• Opium alkaloids• Semisynthetic opioids

• Oxycodone• Hydrocodone• Hydromorphone

Systemic pain control

• NSAIDS • Opioids• Endogenous• Opium alkaloids• Semisynthetic opioids• Synthetic opioids

• Methadone• Fentanyl

Systemic pain control

• NSAIDS • Opioids• Endogenous• Opium alkaloids• Semisynthetic opioids• Synthetic opioids

Learn 1 or 2 from each exogenous group. Get good at these.

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Systemic pain control

• NSAIDS • Opioids• Side effects

• Respiratory suppression• Nausea, vomiting• Constipation

• Loperamide is opium derived

• Habituation and addiction• Not related to pain relief

Alternative methods

• Cold: Ice cube to injection site• EMLA/TAC: topically with occlusive dressing• Voice: Speak in easy, warm tones. (Like some lectures…)• Distraction: headphones, games, screen time, movies• Sensory inhibition: Proximal stimulation inhibits spinal transmission.• Anticipatory instruction: truthful, non-priming• Presence: It is truly surprising how much effect your competent

presence can have. Just be there!

Alternative methods – acute

• Consider ketamine• Dissociative, very safe• 1 – 3 mg/kg IV

• Procedural sedation• Propofol 1 mg/kg

• Have support staff

• Intra-articular lidocaine• Use U/S to visualize• Great for shoulders!• Hip fractures

• Nitrous oxide• 50/50 or 70/30• Use with regulator and scavenger

• Narcs by alternate routes• Intranasal• Intra-articular• Local infiltration

• Diphenhydramine works!• Local infiltration

• Tricyclics

Practical application – local

• Decision cascade: what is the least harm for the greatest effect?• Local usually best

• Toxicity from too much (lidocaine) → OR safer• Regional block for large or painful areas, scant soft tissue

• Soles of feet, face, teeth, hands• Femoral N block for hip fracture

• Plexus block for limb work• Scalene block may result in intrathecal spread

• Spinal block, esp. for OB work• High blocks or recumbent position can result in respiratory arrest.• Anesthesiologist territory, usually

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Practical application – local extended

• Prolonged pain relief during most intense pain time

• Extended duration local

• Lidocaine with epi 2 – 4 h), bupivacaine plain (4 – 6h) or with epi (6 – 8h)

• Extended infusion local

• Continuous peripheral nerve blocks (IV catheter with local infiltration (Bier))

• Adjuvants/augmenters local/perineural

• SSRI, local opioid, NDMA (ketamine), NSAIDS, steroids (dexamethasone)

• Long acting and controlled release local

• Liposomal based, nano-particle, polymer based

• Expensive (in ultra-short term)

• Entire seminar here…

• More

Practical application – systemic

• Decision point: NSAID or opioid?• NSAIDs are equipotent to narcs for pain relief

• Pediatric fractures: ibuprofen at least as good as morphine.• NSAIDs fail euphoria; feeling good is not a bad thing.

• NSAIDs are preferable for some severe pain• Ketorolac best for occlusive pain: kidney stone, cholecystitis• OK to use euphoric drugs first but keep expectations low.

• History of narcotic abuse• It’s OK to ask!

• True allergy• Risk avoidance; there are other treatments.

Tetanus

• Don’t forget to update tetanus.• When in doubt, just give it to them.

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Tetanus

• Don’t forget to update tetanus.• When in doubt, just give it to them.

• Administer TIG for highly contaminated wounds.• Crush injury• Soil• Uncertain Td status, especially elderly

Tetanus

• Don’t forget to update tetanus.• When in doubt, just give it to them.

• Administer TIG for highly contaminated wounds.• Crush injury• Soil• Uncertain Td status, especially elderly

• Use Pertussis in elderly to protect infants.

Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

• Side effect ≠ allergy• GI disturbance• Hypertension exacerbation

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Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

• Side effect ≠ allergy• GI disturbance• Hypertension exacerbation

• Special cautions• Samter’s triad• ASCVD• CHF

• Why?

Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

• Side effect ≠ allergy• GI disturbance• Hypertension exacerbation

• Special cautions• Samter’s triad• ASCVD• CHF

• Why?

• Opioid• Systemic symptoms

• True anaphylaxis

Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

• Side effect ≠ allergy• GI disturbance• Hypertension exacerbation

• Special cautions• Samter’s triad• ASCVD

• CHF• Why?

• Opioid• Systemic symptoms

• True anaphylaxis

• Side effect ≠ allergy• Itching along infusion route

• Direct histamine releaser

• Somnolence• Nausea, vomiting

• Mental status changes

Allergy

• NSAID• Systemic symptoms

• Airway swelling• Anaphylaxis

• Side effect ≠ allergy• GI disturbance• Hypertension exacerbation

• Special cautions• Samter’s triad• ASCVD

• CHF• Why?

• Opioid• Systemic symptoms

• True anaphylaxis

• Side effect ≠ allergy• Itching along infusion route

• Direct histamine releaser

• Somnolence• Nausea, vomiting

• Mental status changes

• Special cautions• Addiction history

• Hypotension

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Panic is not a plan. When things go south…

• NSAIDs• Supportive care; stop agent!

• GI bleed• Misoprostol, antacids

• Renal failure• Stop meds

• Acute allergy: usual care

Panic is not a plan. When things go south…

• NSAIDs• Supportive care; stop agent!

• GI bleed• Misoprostol, antacids

• Renal failure• Stop meds

• Acute allergy: usual care

• Locals (Lidocaine, etc.)• Benzodiazepine for seizure• Prevention by limits

Panic is not a plan. When things go south…

• NSAIDs• Supportive care; stop agent!

• GI bleed• Misoprostol, antacids

• Renal failure• Stop meds

• Acute allergy: usual care

• Locals (Lidocaine, etc.)• Benzodiazepine for seizure• Prevention by limits

• Opioids• Supportive care• Naloxone• Intubate• Prolonged observation• Adult conversation

Panic is not a plan. When things go south…

• NSAIDs• Supportive care; stop agent!

• GI bleed• Misoprostol, antacids

• Renal failure• Stop meds

• Acute allergy: usual care

• Locals (Lidocaine, etc.)• Benzodiazepine for seizure• Prevention by limits

• Opioids• Supportive care• Naloxone• Intubate• Prolonged observation• Adult conversation

• Acetaminophen• N-acetyl cysteine

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Dosing, general guidelines

• NSAIDs• Ceiling effect

• Pain ≠ inflammation• Use ½ top dose• Limit toxicity, maximize pain control

• Ibuprofen 400 mg max.• Ketorolac 15 mg IV (maybe 7.5 mg)

Dosing, general guidelines

• NSAIDs• Ceiling effect

• Pain ≠ inflammation• Use ½ top dose• Limit toxicity, maximize pain control

• Ibuprofen 400 mg max.• Ketorolac 15 mg IV (maybe 7.5 mg)

• Acetaminophen• 650 mg po sufficient• IV formulation only when NPO ($)

Dosing, general guidelines

• NSAIDs• Ceiling effect

• Pain ≠ inflammation• Use ½ top dose• Limit toxicity, maximize pain control

• Ibuprofen 400 mg max.• Ketorolac 15 mg IV (maybe 7.5 mg)

• Acetaminophen• 650 mg po sufficient• IV formulation only when NPO ($)

• Opioids• Morphine 0.1 mg/kg IV• Fentanyl 50 μg IV

• Rigid chest syndrome very rare• Hydromorphone 0.5 mg IV• Hydrocodone 5 mg po

• *Continued pain med needs after 5 – 7 days is a red flag.* (Except terminal patients; forgetaboutit.)

Case studies

• Right flank pain in 33 y o male• Sudden onset @ 0435

• Sharp, radiated to right testicle• Associated with nausea and vomiting• No fever, no exposures• No past medical history• Family history: kidney stones

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Case studies

• Right flank pain in 33 y o male• Sudden onset @ 0435

• Sharp, radiated to right testicle• Associated with nausea and vomiting• No fever, no exposures• No past medical history• Family history: kidney stones

• Diagnoses• Kidney stone• Cholecystitis• Appendicitis• Testicular torsion/injury

Case studies

• Right flank pain in 33 y o male• Sudden onset @ 0435

• Sharp, radiated to right testicle• Associated with nausea and vomiting• No fever, no exposures• No past medical history• Family history: kidney stones

• Diagnoses• Kidney stone• Cholecystitis• Appendicitis• Testicular torsion/injury

• Treatment (start before labs back!)• Narcs

• May increase GI symptoms

• Antiemetic (sedating, please)• IV NSAID

• IV special advantage; retention

• Fluids?• Commonly done, no logic

• Send home on:• NSAID• Antiemetic• Peripheral α blocker• Rescue narc (<3 day supply)

Case studies

• Right leg pain in 33 y o male• Sudden onset @ 1435• Novice skiing • Right thigh is deformed• No past medical/surgical hx (yet)• Family hx negative• Diagnoses

• Right femur fx• Right hip dislocation• Torn quadriceps tendon

• Nothing good comes from novice +

Case studies

• Right leg pain in 33 y o male• Sudden onset @ 1435• Novice skiing • Right thigh is deformed• No past medical/surgical hx (yet)• Family hx negative• Diagnoses

• Right femur fx• Right hip dislocation• Torn quadriceps tendon

• Nothing good comes from novice +

• Treatment (start before X-Ray)• Narcs

• Yup!

• Hare traction• More narcs• IV NSAID if allergy or addiction• Consider ketamine

• Surgeon

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A final word about Narcs

Opioid deaths are continuing to increase.Most start road to addiction at our hands.

How can we do a better job of not harming?

A final word about NarcsOpioid deaths are continuing to increase.

Most start road to addiction at our hands.How can we do a better job of not harming?

A framework for understanding (not terminal, etc.!)Some folk have a predilection for addiction; genetics?

Unexposed, they are secure; exposed, they are vulnerable.

A final word about NarcsOpioid deaths are continuing to increase.

Most start road to addiction at our hands.

How can we do a better job of not harming?

A framework for understanding (not terminal, etc.!)

Some folk have a predilection for addiction; genetics?

Unexposed, they are secure; exposed, they are vulnerable.

No one wants to become an addict. (They may like the feelings.)We have no better test than history (so far.)

Have frank discussions; limit exposure in vulnerable populations.

A final word about NarcsOpioid deaths are continuing to increase.

Most start road to addiction at our hands.

How can we do a better job of not harming?

A framework for understanding (not terminal, etc.!)

Some folk have a predilection for addiction; genetics?

Unexposed, they are secure; exposed, they are vulnerable.

No one wants to become an addict. (They may like the feelings.)

We have no better test than history (so far.)

Have frank discussions; limit exposure in vulnerable populations.

Once started, stop soon and very soon; continuation is not a help.Continued requests beyond acute phase are from habituation.

Gray hair is no protection and is a danger (falls, etc.)

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A final word about NarcsOpioid deaths are continuing to increase.

Most start road to addiction at our hands.

How can we do a better job of not harming?

A framework for understanding (not terminal, etc.!)

Some folk have a predilection for addiction; genetics?

Unexposed, they are secure; exposed, they are vulnerable.

No one wants to become an addict. (They may like the feelings.)

We have no better test than history (so far.)

Have frank discussions; limit exposure in vulnerable populations.

Once started, stop soon and very soon; continuation is not a help.

Gray hair is no protection and is a danger (falls, etc.)

Continued requests beyond acute phase are from habituation.

This is a very difficult area; we’ve let it become about morality.Get active; become part of the solution, not part of the problem.

https://www.wsj.com/articles/opiod-use-soars-among-middle-aged-and-elderly-1492999801

Beers list

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Pain mitigation strategies you can use

• Adequate sleep• Now there’s research! Sleep helps mitigate pain, disordered sleep amplifies it.

Resources

• Dorsal horn signal processing• Review of pain management• Local anesthetics review• Overview of opioids• Acetaminophen reduces social pain• Pediatric pain relief with ibuprofen• Prescriber’s Letter, Beers list• 2015 Beers list

Resources

• America’s Deadly New Normal: US News and World Report

• The Promotion and Marketing of OxyContin: Commercial Triumph, Public Health Tragedy

• After the Overdose (AP)

Clattenburg EJ, Nguyen A, Yoo T, Flores S, Hailozian C, Louie D,

Herring AA. Intravenous Lidocaine Provides Similar Analgesia to

Intravenous Morphine for Undifferentiated Severe Pain in the

Emergency Department: A Pilot, Unblinded Randomized

Controlled Trial. Pain Med. 2018 May 7 [Epub ahead of print].

doi: 10.1093/pm/pny031. PMID: 29741660

Ghost ship lobbyists

• Organization hiding actual goals: Ghost lobbying• Citizens for American Ideas

• Against drug cost lowering in Medicare• IP address hidden, UPS mailbox store address

• Alliance for Patient Access• Opposes reduction in drug reimbursement for Medicare B (not D) drugs• Physician led, drug company sponsored

• Patients Rising• Opposes Medicare negotiation of drug pruices• Drug company sponsored

• Source: Washington Post

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