Postoperative Pain Management

Dr. Hriday Ranjan Dr. Hriday Ranjan RoyRoy

Assistant Professor, Assistant Professor,

Surgery,Surgery,

Rangpur Medical Rangpur Medical College, Rangpur, College, Rangpur,

Bangladesh Bangladesh

What’s the definition of What’s the definition of pain?pain?

Pain is a Pain is a SensorySensory and and EmotionalEmotional experience associated with tissue experience associated with tissue damage or described in damage or described in terms of suchterms of such damagedamage

(I.A.S.P)(I.A.S.P)(The International Association for

the Study of Pain)

Pain is Always Pain is Always Subjective Subjective and Can and Can Never be Never be Proved or Proved or Disproved.Disproved.

TOTAL RECALL

The Pain Pathways and The Pain Pathways and MechanismsMechanisms

Substance P acts on mast cells in the vicinity of sensory endings and release of histamine, which

directly excites nociceptors. Substance P and CGRP produces dilation of

peripheral blood vessels. The resultant edema causes additional liberation of bradykinin.

Thus Nociceptors activate and cause pain.

Substance P : A short chain Polypeptide, a neurotransmitter that caries pain impulse from peripheral nervous system to Central nervous System

Ref: E. (Kandel et al, Principles of Neural Science, 2000, p. 481)

How Pain Occurs Tissue damage releases bradykinin and

prostaglandins, which activate or sensitize nociceptors.

Activation of nociceptors leads to the release of substance P and calcitonin gene related peptide (CGRP).

Pain PathwaysPain Pathways

Frenchman Rene Descartes, De humine textbook

Axon Reflex

Np : Neuro-peptides, BV : Blood Vessels

PathophysiologyPathophysiology

• The generation of pain The generation of pain involves interaction involves interaction between all parts of the between all parts of the nervous system.nervous system.

Pain ultimately transmitted to:• Thalamus• Medulla oblongata• Cerebral cortex.

Fast Pain: Felt within 0.1 second after painful stimulus.

Also called: sharp pain, pricking pain, electric pain and acute pain.

Slow Pain: Felt within 1.0 second or more after painful stimulus.

Also called: dull pain and chronic pain.

Types of PainTypes of Pain

Types of PainTypes of Pain

1. Nociceptive pain- Direct stimulation of intact 1. Nociceptive pain- Direct stimulation of intact nociceptorsnociceptors

• Transmission along normal nervesTransmission along normal nerves

• Sharp, aching, throbbingSharp, aching, throbbing– somaticsomatic

• easy to describe, localizeeasy to describe, localize

– visceralvisceral• difficult to describe, localizedifficult to describe, localize

2. Neuropathic pain . . .2. Neuropathic pain . . .• Disordered peripheral or central nervesDisordered peripheral or central nerves

• Compression, transection, infiltration, Compression, transection, infiltration, ischemia, metabolic injuryischemia, metabolic injury

• Varied typesVaried types– peripheral, deafferentation, complex regional peripheral, deafferentation, complex regional

syndromessyndromes

• Pain may exceed observable injury Pain may exceed observable injury

• Described as burning, tingling, shooting, stabbing, Described as burning, tingling, shooting, stabbing, electrical electrical

• MMxx: opioids, adjuvant / coanalgesics often req.: opioids, adjuvant / coanalgesics often req.

Assessment of Assessment of PainPain

How doHow do

YouYou

QuantifyQuantify

pain?pain?

Pain rating scalesPain rating scalesCategorical scale

Visual analogue scale (VAS)

Numeric rating scale

0No pain

1Mild

2Discomforting

3Distressing

4Intense

5Excruciating

No pain Most pain

0 2 4 6 8 101 3 5 7 9

( 0 = No pain, 10 = Worst pain imaginable )

““Ten Scale” most common: 11 point scaleTen Scale” most common: 11 point scale– 0 = No pain0 = No pain

– 10 = Worst pain imaginable10 = Worst pain imaginable

•PAIN PAIN MANAGEMENTMANAGEMENT

Pain Management in the late 18Pain Management in the late 18thth centurycentury

Barker M.D.

PainPain ManagementManagement

Different Pain Different Pain management Modalitiesmanagement Modalities

Pre-emptive AnalgesiaPre-emptive Analgesia

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

• local anesthetic infiltration of the skin local anesthetic infiltration of the skin

• Effective dose of systemic opioids Effective dose of systemic opioids

• Systemic nonsteroidal anti-Systemic nonsteroidal anti-inflammatory drugs (NSAIDs) inflammatory drugs (NSAIDs)

• Neuroaxial opioids or local anesthetic Neuroaxial opioids or local anesthetic

• Peripheral nerve blocksPeripheral nerve blocks

Patient Controlled AnalgesiaPatient Controlled AnalgesiaPCAPCA

1. Increase patient satisfaction1. Increase patient satisfaction

2. Decrease side effects and 2. Decrease side effects and complicationscomplications

3. Decrease sedation3. Decrease sedation

4. Decrease total amount of daily 4. Decrease total amount of daily opioidsopioids

5. 5. Avoid Avoid Basal rateBasal rate in the Elderly in the Elderly6. PCA Flowsheets6. PCA Flowsheets

Regional analgesiaRegional 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 BlocksNeuroaxial Blocks

Opioid Spread after Epidural injection

Adjuvant TherapyAdjuvant Therapy

Nonsteroidals Nonsteroidals

Conformational structure of COX-1 Conformational structure of COX-1 and COX-2 isozymesand COX-2 isozymes

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

NSAID'sNSAID's

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

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

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

possible in combination with Epidural,possible in combination with Epidural, IV,or oral narcotics IV,or oral narcotics

Practical guide for NSAID’s Practical guide for NSAID’s UsageUsage

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

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

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

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

• Please check the patient renal function routinely Please check the patient renal function routinely prior to administrationprior to administration

• COX2 inhibitors doesn’t affect the platelet functionCOX2 inhibitors doesn’t affect the platelet function

Practical guide for NSAID’s Practical guide for NSAID’s UsageUsage(Continuum)(Continuum)All specific or non-specific NSAID’s may All specific or non-specific NSAID’s may

cause:cause:

• water retention and edemawater retention and edema

• HypertensionHypertension

• Renal dysfunctionRenal dysfunction

• May delay bony fusion in chronic May delay bony fusion in chronic usage ?usage ?

ClonidineClonidine

• Alpha2 agonist with outstanding Alpha2 agonist with outstanding properties when administered properties when administered intrathecally:intrathecally:

• Pain control properties by itselfPain control properties by itself• Decrease the requirement of narcoticsDecrease the requirement of narcotics• Decrease toleranceDecrease tolerance• Great for neuropathic pain controlGreat for neuropathic pain control• Adding 1mcg/kg for children caudal block Adding 1mcg/kg for children caudal block

will extend pain relief up to 24hwill extend pain relief up to 24h

ClonidineClonidine

Oral or transdermal Clonidine:Oral or transdermal Clonidine: Enhance the effect of narcoticsEnhance the effect of narcotics Decreases the daily narcotic Decreases the daily narcotic

requirementrequirement Excellent Excellent AdjuvantAdjuvant therapy for therapy for

narcotic dependent patientsnarcotic dependent patients Effective for neuropathic painEffective for neuropathic pain

Coanalgesic AgentsCoanalgesic Agents

• Anxiolytic drugsAnxiolytic drugs

• AnticonvulsantsAnticonvulsants

• AntidepressantsAntidepressants

• KetamineKetamine

KetamineKetamine

• NMDA receptors antagonist NMDA receptors antagonist Neuropathic painNeuropathic pain

• Potent analgesic effectPotent analgesic effect• Small doses in combination of opioids Small doses in combination of opioids

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

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

Mechanisms of Anti-Epileptic Mechanisms of Anti-Epileptic Drugs in PainDrugs in Pain

Usage of Anti-Epileptic Drugs in Usage of Anti-Epileptic Drugs in Acute PainAcute Pain

• Every surgical incisional pain has Every surgical incisional pain has Neuropathic componentNeuropathic component

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

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

• These class of drugs are also mode These class of drugs are also mode stabilizersstabilizers

Non Chemical TechniquesNon Chemical Techniques

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

• TENS UnitsTENS Units

• PhysiotherapyPhysiotherapy

The W.H.O 3-step Pain “Ladder”The W.H.O 3-step Pain “Ladder”

• Step 1 (Step 1 (mildmild))::– non opioid non opioid ++ adjuvant adjuvant

• Step 2 (moderate):Step 2 (moderate):– ““weak” opioid weak” opioid ++ step 1 meds step 1 meds

• Step 3 (severe) :Step 3 (severe) :– ‘‘strong’ opioidstrong’ opioid++step 1 medsstep 1 meds

Codeine Hydrocodone

Oxycodone Dihydrocodeine

Tramadol ± Adjuvants

Nalbuphine Morphine

Hydromorphone Methadone

Levorphanol Fentanyl

Oxycodone ± Adjuvants

ASA Acetaminophen

NSAIDs ± Adjuvants

Physiological vs clinical painPhysiological vs clinical pain

• Physiological pain has a biological Physiological pain has a biological functionfunction

• Pathological pain has no biological Pathological pain has no biological functionfunction

Woolf

Multidisciplinary ApproachMultidisciplinary Approach

Acute Pain Team

PharmacistNurse

AnaesthetistPhysiotherapist

Psychologist

Surgeon

Pain after surgeryPain after surgery

• Inflammatory painInflammatory pain

• Nociceptive painNociceptive pain

• Neuropathic painNeuropathic pain

Inflammatory painNociceptive pain

Neuropathic pain

Chronic post surgical painChronic post surgical pain

• Pain developed after a surgical Pain developed after a surgical procedureprocedure

• At least 2 month durationAt least 2 month duration

• Other causes excluded (malignancy, Other causes excluded (malignancy, chronic infection)chronic infection)

• Possibility of continuous pain of pre-Possibility of continuous pain of pre-existing problemexisting problem

Macrae 2001

Principles of analgesic PlanPrinciples of analgesic Plan

• Balanced analgesiaBalanced analgesia

• Opioids: First line morphineOpioids: First line morphine

• Regional analgesiaRegional analgesia

• Actual dose of analgesics will not be Actual dose of analgesics will not be discusseddiscussed

• Regular and breakthrough prescription Regular and breakthrough prescription including night-timeincluding night-time

Analgesic ladder

Non-opioid AnalgesicsNon-opioid Analgesics

• Paracetamol:Paracetamol: Acetaminophen Acetaminophen centrally acting centrally acting 500mg-1g 6h or 15-500mg-1g 6h or 15-20mg/kg for children20mg/kg for children

• Diclofenac sodium:Diclofenac sodium: 50mg TDS orally50mg TDS orally

• Aspirin:Aspirin: 300-900mg 300-900mg 4h4h

• NSAIDs:NSAIDs: Analgesic, Analgesic, antipyretic,antiinflamantipyretic,antiinflammatorymatory

• Opioid sparingOpioid sparing

• SE:SE: Prostaglandin and Prostaglandin and prostacyclin effectprostacyclin effect

• Ibuprofen,Ibuprofen, diclofenac, diclofenac, naproxen, piroxicamnaproxen, piroxicam

Opioid AnalgesicsOpioid Analgesics

• Weak opioidsWeak opioids

Codeine phosphate 30-Codeine phosphate 30-60mg 4h60mg 4h

Dihydrocodeine 30mg 4-6h Dihydrocodeine 30mg 4-6h po or 50mg 4-6h impo or 50mg 4-6h im

Buprenorphine 200-Buprenorphine 200-400mcg sl 4-6h400mcg sl 4-6h

Tramadol weak agonist 50-Tramadol weak agonist 50-100mg 4h100mg 4h

• Strong opioidsStrong opioids

NalbuphineNalbuphine

MorphineMorphine

DiamorphineDiamorphine

Pethidine: max Pethidine: max 1.2g daily1.2g daily

Prevalence of chronic pain following surgeryPrevalence of chronic pain following surgery

Surgery Perkins & Kehlet Macrae

Breast 11-49% 23-49%

Thoracotomy 22-67% 5-67%

Cholecystectomy 3-56% 3.4-27%

Inguinal Hernia 0-37% 15-63%

Vasectomy N/A 0-37%

Neuropathic pain canNeuropathic pain can becomebecome established extremely quickly after established extremely quickly after

trauma and surgerytrauma and surgery and and remain remain unchanged after 6 monthsunchanged after 6 months