what’s the definition of pain? pain is a sensory and emotional experience associated with tissue...

What’s the definition of pain?

Pain is a Sensory and Emotional experience associated with tissue damage or described in terms of such damage

(I.A.S.P.)

The Pain Pathways and Mechanisms

Pain Pathways

Frenchman Rene Descartes, De humine textbook

Aß Fibers C Fibers

Axon Reflex

Np : Neuro-peptides, BV : Blood Vessels

Physiology of the dorsal horn of the spinal cord

HyperalgesiaAnd pain Threshold inhumans

Pain Management in the late 18th century

Barker M.D.

Different Pain management Modalities

Pre-emptive Analgesia Pre-emptive analgesia can be achieved by:

• local anesthetic infiltration of the skin

• Effective dose of systemic opioids

• Systemic nonsteroidal anti-inflammatory drugs (NSAIDs)

• Neuroaxial opioids or local anesthetic

• Peripheral nerve blocks

Patient Controlled AnalgesiaPCA

1. Increase patient satisfaction

2. Decrease side effects and complications

3. Decrease sedation

4. Decrease total amount of daily opioids

5. Avoid Basal rate in the Elderly6. PCA Flowsheets

Regional analgesia

Isolated Extremity Injury

Brachial plexus Anatomy

Infraclavicular Approach

Infraclavicular Approach

Lower Extremity Injury

Paravertebral Lumbar Somatic Nerve Block

Femoral Nerve Block

Sciatic Nerve Block

Neuroaxial Blocks

Opioid Spread after Epidural injection

CSF Circulation

Each of the four ventricles of the brain has a choroid plexus and CSF normally circulates between them:  

1. The foramen of Monro is an opening from the lateral ventricle into the third ventricle 

2. The aqueduct of Sylvius is the pathway of CSF flow between the  third and fourth ventricles

3. The foramina (plural of "foramen") of Magendie and Luschka are openings from the fourth ventricle into the subarachnoid space around the base of the brain and upper spinal cord   

  4. The daily production is around 400-600 ml/ day

5. The reabsorption occurs over the surface of the brain and into the venous dural sinus drainage channels

Spread of Opioids in CSF

Pharmacokinatics of Epidural injection of Hydrophilic Drug

Pharmacokinatics of Epidural Lipophilic Opioid

Effects of Increased Pressure on Venous drainage“Pregnancy, Morbid obesity”

Complications of Epidural Morphine

Morphine concentration in Cervical CSF after lumbar Epidural injection

Epidural Homodynamic Facts

• Local anesthetics may cause vasodilatation and hypotension (Sympathectomy)

• Narcotics dose not cause Hypotension• Not every post-op hypotension is related to

Epidural analgesia.• Epidural analgesia promotes early mobilization• Nausea & vomiting response to small doses of

Narcan or Zofran. Avoid Phenergan

Tunneling Technique

Adjuvant Therapy

Nonsteroidals

Conformational structure of COX-1 and COX-2 isozymes

COX-1 (A) COX-2 (B)

NSAID's

• Blocks the production of Prostaglandin• Very effective in pain control, Alone or in

Combination with Narcotics• Ketorolac is My drug of choice as an

adjunct therapy in acute pain• Use p.o. forms “Cox2 inhibitors” when

possible in combination with Epidural, IV,or oral narcotics

Practical guide for NSAID’s Usage

• Pre-op administration significantly decreases post-op pain and cramps

• Toradol 30mg, IV or Celebrex 400mg, P.O. pre-op• For sever acute pain Celebrex 400mg, P.O. bid X one

week the 200 P.O., bid. Bextra 20mg, bid X one week the 20mg, QD

• PPI are the drugs of choice to treat gastric complications. H2 blockers only mask the disease

• Please check the patient renal function routinely prior to administration

• COX2 inhibitors doesn’t affect the platelet function

Practical guide for NSAID’s Usage(Continuum)

All specific or non-specific NSAID’s may cause:• water retention and edema• Hypertension• Renal dysfunction• May delay bony fusion in chronic usage ?

Clonidine• Alpha2 agonist with outstanding properties

when administered intrathecally:• Pain control properties by itself• Decrease the requirement of narcotics• Decrease tolerance• Great for neuropathic pain control• Adding 1mcg/kg for children caudal block

will extend pain relief up to 24h

Clonidine

Oral or transdermal Clonidine: Enhance the effect of narcotics Decreases the daily narcotic requirement Excellent Adjuvant therapy for narcotic

dependent patients Effective for neuropathic pain

Coanalgesic Agents

• Anxiolytic drugs

• Anticonvulsants

• Antidepressants

• Ketamine

Ketamine

• NMDA receptors antagonist Neuropathic pain

• Potent analgesic effect• Small doses in combination of opioids

substantially improve pain control• Bolus dose of 100 mcg/kg followed by a

continuous drip of 1-3 mcg/kg/min is ideal for chronic opioid users postoperatively

Mechanisms of Anti-Epileptic Drugs in Pain

Usage of Anti-Epileptic Drugs in Acute Pain

• Every surgical incisional pain has Neuropathic component

• Studies showed giving 1200 mg of Gabapentin 1 h prior to surgery decreases the opioids requirement post-op and results in better pain control without increased sedation

• Combining Gabapentin with opioids is ideal for re-do back surgery cases with chronic opioids usage

• These class of drugs are also mode stabilizers

Non Chemical Techniques

• Psychological treatments: Relaxation, hypnosis Cognitive therapy etc..

• TENS Units

• Physiotherapy

Pain Management Algorithm

Trauma pain managementAlgorithm

Trea t w ith an ym od a lit ies

C lear m en ta ls ta tu s

S m all d oses o fop io id s (cod e in e)o r/w ith K e to ro lac

U n c lear m en ta ls ta tu s

H ead in ju ryp a tien ts

Trauma pain managementAlgorithm

E p id u ra l an a lg es iaop io id s o r

loca l an es th e tic s

B on e in ju ry

E p id u ra l an a lg es iaO p io id s on ly

P C A

yes

E p id u ra l op io id sw ith o r w ith ou t

loca l an es th e tic s

P erip h era ln e rve b lock

N o

N erve fu n c tionm on ito rin g

P erip h era l n e rve o r vascu la rin ju ry

E xtrem ity in ju ry

Trauma pain managementAlgorithm

E p id u ra l an a lg es ia

S u rg ery req u ired

P C A

S u rg ery n o t rq u ired

A b d om in a l in ju ry

Trauma Pain Management Algorithm

P C A

S p in a l co rd in ju ry

E p id u ra l an a lg es iaw ith loca l an es th e tic s

(V ery e ffec tive )

P O /IV N arco tic sA n tid ep ressan tsA n ticon vu lsan ts

C R P S IC R P S II

N eu rop a th icn erve in ju ry

N eu ro log ic in ju ries

Trauma pain managementAlgorithm

Th orac ic ep id u ra lan a lg es ia

In te rcos ta ln erve b lock

P C A

R ead y fo rextu b a tion

IV n arco tic sP C A

In tu b a tedp a tien ts

Th orac ic ep id u ra lan a lg es ia

In te rcos ta ln erve b lock

P C A

N ot In tu b a tedp a tien ts

Th orac ic trau m a

Pharmacokinatic model of Spinal injection of Hydrophilic Opioid

Referred Pain

Bardram et al: [8] eight elderly high-risk patients, stress-free (i.e., laparoscopic) colonic resection

Combination of laparoscopic surgery, epidural analgesia, early

oral nutrition, and early mobilization

Pain relief → early mobilization in elderly patients → accelerated

recovery; hospital stay: 2 d

Moiniche et al: [111] uncontrolled pilot investigation, 17 patients, open colonic resection

Combined epidural–general anesthesia, epidural analgesia, no

nasogastric tube, oral feeding in 24 h, early mobilization

VAS 0 at rest, minimal with mobilization; normal defecation in

12 patients within 48 h; median hospital stay: 5 d

Liu et al: [95] 54 patients, four groups, partial colectomy

Multimodal recovery program Epidural analgesia: superior; earlier recovery of gastrointestinal function

but more orthostatic hypotension; epidural bupivacaine combined with morphine: best balance of analgesia

and side effects

Collier: [29] 186 patients, care pathway for elective carotid endarterectomy

Preoperative education, same-day admission, regional anesthesia,

selective use of ICU

10% ICU admission; 157 patients discharged on first postoperative day; average stay: 1.27 d; cost-

savings $3000 per patient

Reference Intervention Findings

PUBLICATIONS ON ACCELERATED OR MULTIMODAL POSTOPERATIVE REHABILITATION PROGRAMS

References Intervention Findings

Moiniche et al: [112] 13 patients, hip replacement pilot investigation

Epidural analgesia (bupivacaine-morphine), ibuprofen, intensive mobilization regime

11 patients ready for discharge on day 6, 2 patients discharged on day 9 (usual

hospitalization was 13 d)

Pedersen et al: [126] prospective study, breast surgery, questionnaires from 373 patients

Standardized clinical protocols, support from senior management, expanded educational

resources for patients

Length of stay: 39% decrease; patient volume: up 22%; low incidence of surgical

complications, high patient acceptance

Weingarten et al: [173] retrospective study, 230 patients, total hip replacement

Practice guideline: 5-d postoperative stay in low-risk patients

Practice guideline can reduce hospital length of stay from 8.4 to 5.9 d

Bardram et al: [8] eight elderly high-risk patients, stress-free (i.e., laparoscopic) colonic resection

Combination of laparoscopic surgery, epidural analgesia, early oral nutrition, and

early mobilization

Pain relief → early mobilization in elderly patients → accelerated recovery; hospital

stay: 2 d

Moiniche et al: [111] uncontrolled pilot investigation, 17 patients, open colonic resection

Combined epidural–general anesthesia, epidural analgesia, no nasogastric tube, oral

feeding in 24 h, early mobilization

VAS 0 at rest, minimal with mobilization; normal defecation in 12 patients within 48 h;

median hospital stay: 5 d

Liu et al: [95] 54 patients, four groups, partial colectomy

Multimodal recovery program Epidural analgesia: superior; earlier recovery of gastrointestinal function but more

orthostatic hypotension; epidural bupivacaine combined with morphine: best balance of

analgesia and side effects

PUBLICATIONS ON ACCELERATED OR MULTIMODAL POSTOPERATIVE REHABILITATION PROGRAMS