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Prof. mridul m. panditrao's pain pathophysiology, management & role of anaesthesiologist
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Transcript of Prof. mridul m. panditrao's pain pathophysiology, management & role of anaesthesiologist
Pain!!!!!
Dr. Mridul M. Panditrao
CONSULTANT DEPARTMENT OF ANESTHESIOLOGY AND INTENSIVE CARE
RAND MEMORIAL HOSPITAL
FREEPORT, GRAND BAHAMA
THE COMMONWEALTH OF BAHAMAS
Till 18th century there was nothing!
Remedies like Opium, Alcohol, Mandragora,
soporific sponges and Magical potions were
tried, but the dark ages of “Pain and suffering”
continued unabated
A universal problem!
For eternity, it has plagued mankind
Pain
AGE OF DARKNESS
NO ANALGESIANO ANAESTHESIA
NO DEFINED SURGERY
“AGONY GALORE!!!”
BARBARIC PRACTICES
WOODEN BOWL & WOODEN HAMMER”
PARTIAL STRANGULATION
“WHISKY BOTTLE: ½ YOU & ½ ME”
MAGIC & WITCH-CRAFT
MANDRAGORA / HASHISH / HERBS
‘ DECREE OF CHURCH’
METHODS OF PAIN RELIEF
“ DAWN OF ANALGESIA ”
FREDERICH SERTURNER:1806 MORPHINE
“LAUGHING GAS ” PARTIES & HORACE WELLS : Dec. 10, 1844, N2O IN
DENTISTRY
DEBACLE OF N2O DEMONSTRATION & SETBACK
GQC COLTON : RE-INTRODUCES N2O AS A CARRIER GAS
SWEET OIL OF VITRIOL (“WHIFF OF ETHER”)
16TH OCTOBER 1846
William Thomas Greene MORTONUSHERING IN OF “ ERA OF
ANAESTHESIA”
“INVENTOR AND REVEALER OF ANESTHETIC INHALATIONBEFORE WHOM IN ALL TIME, SURGERY WAS AGONY
BY WHOM PAIN IN SURGERY WAS AVERTED AND ANNULLEDSINCE WHOM SCIENCE HAS CONTROL OF PAIN”
WORLD ANAESTHESIA DAY
“GOOD OUT OF BAD”
LEAF CHEWING NATIVES OF ANDIES (PERU & BOLIVIA): “NUMBNESS OF
MOUTH”
COCAINE
ADVENT OF LOCAL ANALGESICS
REGIONAL: SPINAL, EPIDURAL, FIELD
“POST-OPERATIVE ANALGESIA”
“MORPHINE & COMPANY”
• NEWER OPIOIDS: FENTANYL….• “NEURO-LEPT ANAESTHESIA”• ENDOGENOUS OPIOIDS:
ENDORPHINES, ENCEPHALINS• OPIOID RECEPTORS: μ, κ, σ, δ, ε• “CUSTOM OPIOIDS” : REMIFENTANIL
INTRODUCTION
For All The Happiness Mankind can gain.Is not in pleasure
But in rest from “pain”
JOHN DRYDEN
INTRODUCTION (Contd.)
MAGNITUDE Of PROBLEM Millions of Post-op pts : 48-53% unrelieved Moderate pain in hospitalized pts: ~ 40% Child- bearing age group females : 35-43% Ch. Non-oncogenic pain; Ch. Arthritis : 25-30% Cancer Patients suffering from pain: 80%+
Panditrao MM, Pain and it’s Physiological considerations, eds, Deshpande S et al. Principles of Anaesthesia, Paras, Hyderabad, 1st edition. 2007 : 180
INTRODUCTION (Contd.)
Nociception: Transduction Transmission Modulation Perception
“Gate Control Theory of Melzac & Wall” : 1965
INTRODUCTION (Contd.)
“Reynolds Theory of ‘Supra-Spinal Descending Control in Modulation in Dorsal Horn’ ”: 1969
“Woolf C.J - Supra spinal inhibition of nociception” : 1989
INTRODUCTION (Contd.)
Definition
The International Association for the Study of Pain
“Unpleasant sensory & emotional experience associated with actual or potential tissue damage or described in term of such damage.”
CLASSIFICATION OF PAIN
• Origin
• Pathology
• Onset & Duration
Classification of Pain by Origin
Somato-sensory Pain
Deep Visceral Pain
Referred Pain
Psychogenic Pain
Classification of Pain by Pathology
Nociceptive pain
Neuropathic Pain
Classification of Pain by Onset & Duration
1. Acute- a) Surgical- (i) Pre-operative(ii) Intra-operative(iii) Post-operative
b) Non-surgical- (i) Traumatic(ii) Organic- Physiological
Pathological(iii) Psychosomatic
Classification of Pain by Onset & Duration
2. Chronic- a) Oncogenic
b) Non-oncogenic (i) Organic
(ii) Neuropathic
• Hyperesthesia• Hyperpathia• Hypesthesia• Neuralgia• Paresthesia• Radiculopathy
Terms Used In Pain Management
Terms Used In Pain Management
• Allodynia• Analgesia• Anesthesia• Anesthesia dolorosa• Dysesthesia• Hypalgesia• Hyperalgesia
Psychological and behavioural response to acute pain
fear
general sense of unpleasantness or unease
Anxiety
Negative emotions: depression
Sleep deprivation
Existential suffering: may lead to
patients seeking actively end of life.
Psychological response to chronic pain
Intermittent pain produces a physiologic response similar to acute pain.
Persistent pain allows for adaptation (functions of the body are normal but the pain is not relieved)
Chronic pain produces significant behavioural and psychological changes
The main changes are:- depression - an attempt to keep pain - related behaviour to a minimum
- sleeping disorders- preoccupation with the pain
- tendency to deny pain
Psychological response to chronic pain
• often is associated with a sense of
hopelessness and helplessness• abnormal temperature regulation,
tactile dysfunctionAlteration in sensory function dysfunctions of the general or special senses chronic pain
Immunological effects of Pain
• Decrease natural killer cell counts• Effects on other lymphocytes not yet defined.
Nociception
Transduction Transmission Modulation Perception
Panditrao MM, Pain and it’s Physiological considerations, eds, Deshpande S et al. Principles of Anaesthesia, Paras, Hyderabad, 1st edition. 2007 : 180
Nociception
• “Gate Control Theory of Melzac & Wall” : 1965
Nociception
“Reynolds Theory of ‘Supra-Spinal Descending Control in Modulation in Dorsal Horn’ ”: 1969
“Woolf C.J - Supra spinal inhibition of nociception” : 1989
Peripheral and Central Pathways for Pain
Ascending Tracts Descending Tracts
Cortex
Midbrain
Medulla
Spinal Cord
Thalamus
Pons
(Brookoff, 2000)
Pain-Sensing System in the Malfunction in Chronic Pain
(Illustration: Seward Hung, 2000)
Acute pain:Pain-sensing signals are initiated in response to a stimulus• They elicit a pain-
relieving response
Chronic pain:Pain signals are
generated for no reason and may be intensified
• Pain-relieving mechanisms may be defective or deactivated
Pain Sensing
In chronic pain, pain signals are generated without physiologic significance
Pain Pathway:s & Multimodal Analgesia
From: Gottschalk et al. Am Fam Physician. 2001;63:1979-1984.
Descending modulation
Dorsal horn
Ascendinginput
Spinothalamic tract
Dorsal root ganglion
Peripheral nerve
Peripheral nociceptors
Pain
Trauma
Local anesthetics & blocksOpioids ,2-agonistsNMDA antagonistsInterventional modalities
Opioids 2 -agonists Centrally acting analgesicsCOX-2 selective inhibitorsTraditional NSAIDs
Local anesthetics
Local anesthetics COX-2 selective inhibitors Traditional NSAIDs
Panditrao MM, Pain and it’s Management, eds, Deshpande S et al. Principles of Anaesthesia, Paras, Hyderabad, 1st edition. 2007 : 845
THE ANAESTHESIOLOGISTNOT JUST IN THE OPERATING ROOM
• Operating roomhospitalphysician office
• Labor & delivery suite• Other procedural areas• Intensive care unit• PACU• Pain management
acutechronic / cancer
• “CPCR” team• Respiratory therapy• Administration
operating roomhospitalMedical College
• Educationhealth professionalspublic
• Research
The management of pain is a multidisciplinary team effort involving physicians, psychologists,
nurses, and physical therapists.
Anesthesiologists are ‘physicians and experts’ in the diagnosis and treatment of acute and
chronic pain disorders.
American Society of Anesthesiologists. 2003
ANAESTHESIA
FOR “PAIN MANAGEMENT”:ACUTE : OPERATIVE
PHARMACOTHERAPY & SPECIAL PROCEDURES
REGIONAL & LOCAL BLOCKS
NEURAXIAL PROCEDURES
Pharmacological
Depending upon site of Action
CNS: GAAs, N2O, OpioidsPeripherally :-------- NSAIDS LAAsNeuraxially : -------- ADJUVANTS
Panditrao MM, Pain and it’s Physiological considerations, eds, Deshpande S et al. Principles of Anaesthesia, Paras, Hyderabad, 1st edition. 2007 : 180
Panditrao MM, Pain and it’s Management, eds, Deshpande S et al. Principles of Anaesthesia, Paras, Hyderabad, 1st edition. 2007 : 845
Adjuvants to Neuraxial Blockade: Why needed? Problems of LAAS
• If duration of action to be prolonged? • Motor blockade causing interference with the
mobility of the patient• Sympathetic blockade leading to bradycardia
and hypotension.
• So alternatives to LAAs were tried
ALTERNATIVES TO LAAs:Problems:
• Side effects of Opioids • Difficulty in procuring• Minimal muscle relaxation • Other agents viz. Clonidine, Neostigmine,
Ketamine, Midazolam and their side effects
LAAs & ADJUVANTS
COMBINATION!!!!
Advantages of Adjuvants
• Improvement of quality of block• Onset of analgesic effect of LAAs is enhanced • Duration of action of LAAs is prolonged• Dose requirement of each drug is reduced • Lower incidence of side effects
Routes of Administration
• In sub-arachnoid space when only SA is given
• In epidural space through epidural catheter when Combined Spinal Epidural (CSE) Analgesia is given
Various drugs used as Adjuvants
• Opioids agonists: Morphine, Fentanyl etc. Agonist /antagonist: Butorphanol,
Buprenorphine• Clonidine• Neostigmine• Ketamine• Midazolam• Tramadol
SUB-ARACHNOID BLOCK
Combined Spinal Epidural (CSE)in the Same Intervertebral
Space
Using Combipack
Combined Spinal & Epidural (CSE) in two
different Intervertebral Spaces
CONTINUOUSSUPRA-CLAVICULARBRACHIAL-PLEXUS
BLOCK
CHRONIC PAIN
Prevalence of chronic pain• - 35% in the society• - 40% in females, 31% in males• - 25% ≤ 18 years, 55% ≥ 65 years• 20% of the chronic pain population = postsurgical chronic pain
23rd International Winter Symposium in Leuven, Dr. Jan Maeyaert, 11-12 january 2008
CHRONIC PAIN
Prevalence of chronic pain• - 35% in the society• - 40% in females, 31% in males• - 25% ≤ 18 years, 55% ≥ 65 years• 20% of the chronic pain population = postsurgical chronic pain
23rd International Winter Symposium in Leuven, Dr. Jan Maeyaert, 11-12 january 2008
Prevalence and Impact of Chronic Pain on Society
• Chronic pain is one of the most common conditions for which people seek medical treatment
• 35% of Americans suffer from chronic pain
• >50 million Americans are partially or totally disabled by chronic pain
• 50 million workdays are lost per year
• $100 billion is the estimated annual cost in lost productivity, medical costs, and lost income
(American Pain Society, 2001; Gitlin, 1999; Glajchen 2001; Loesser et al, 2001)
Undertreatment of Chronic Pain>40% to 50% of patients in routine practice
settings fail to achieve adequate pain relief
In a recent study of 805 chronic pain sufferers, >50% had to change physicians to achieve relief because the physician:
was unwilling to treat pain aggressively
did not take the patient’s pain seriously
had inadequate knowledge about pain treatment
(American Pain Society, 2001; Glajchen, 2001; Lister, 1996; Portenoy, 1996)
The story of chronic pain
WHY?- Such a high incidence
- Increasing incidence by aging
- Higher in females
The story of chronic pain
The answer: a CUMULATIVE STATE of
CENTRAL SENSITIZATION over time
Ideal cocktail for
SENSITIZATION
ACUTE SOMATIC
nociceptive
ACUTE VISCERAL
nociception
Psychogenic factors(stress, anxiety)
NEUROGENIC
DAMAGE
CENTRALSENSITIZATION
Somatic Nociceptive
pain(Trauma & Surgery)
VISCERALNOCICEPTIVE
PAIN(renal/biliary
colic,dysmenorhea)
PSYCHOGENIC PAIN
(anxiety, depresseion,
prolonged stress)
NEUROPATHIC PAIN
(nerve dysfunction,nerve injury)
CENTRAL
SENSITIZATIONWIND
UP
If prolonge
d
Damage to the CNS
•Death of inhibitory neurons•Loss of
descending inhibition•Genetic
transformation of
nociceptive neurons from
high to low threshold
INTRACTABLE CHRONIC PAIN UNRESPONSIVE TO ANALGESICS
• Whatever is the initial pain mechanism• All types of unrelieved pain end as
CENTRAL NEUROPATHIC PAIN
CHRONIC PAIN is a provoked irreversibleprogressive or stabledysfunctional or neurodegenerative disease of the CNS
Role of the Anesthesiologist
Define the patients at risk
Development of preventive strategies
Early and prompt diagnosis and treatment
Information of the public and medical community
23rd International Winter Symposium in Leuven, Dr. Jan Maeyaert, 11-12 Januari 2008
Role of the Anaesthesiologist
Define the patients at risk
• Unrelieved acute pain• Anxiety• Depression• Prolonged stress• Nerve damage CNS/PNS• Recurrent surgery• Female sex/genetic predisposition
Role of the Anaesthesiologist
Develop preventive strategies
• Neuraxial or regional nerve blocks• Multimodal pain treatment protocols• Early use of antidepressants and anti-epileptics
in patients with nerve damage• Use of COX-II inhibitors• Opiate sparing strategies
Role of the Anaesthesiologist
Start early diagnosis and treatment when pain persists
• 50% reduction of chronic pain in CVA and postherpetic neuralgia pain patients by starting amitryptiline in the acute phase
• 8 fold decrease of chronic low back pain by starting multimodal therapy in the acute phase
• Patients with acute neuropathic pain after surgery do better when amitryptiline and gabapentin are started early after surgery
Role of the AnaesthesiologistInform the patients / medical community
• Negative consequences of unrelieved pain
• Possibilities to manage the pain
• Inform the surgeons - to use minimal invasive techniques - To take care of neurogenic structures - Repeat surgery for chronic pain is not an option - Surgery in a patient with a chronic pain condition is less successful - To infiltrate the site of incision with long acting local anesthetics
Chronic Pain : Oncogenic
• “Pain is what the patient says hurts!”
• “Accept the pain as what the patient says it is and not what you think it should be”
• “ Your pain is your’s and is real!”
• “Addiction/Dependance has lost it’s significance in these patients”
Chronic Pain : OncogenicTreatment Modalities:
1. Treatment of Disease (cancer) itself2. Analgesics and Adjuvants (WHO ladder)3. Custom Opioids4. Computerized drug Delivery : ‘pumps’.. PCA,
CCIP(Computerized controlled infusion pumps’5. Non-Invasive drug Delivery Devices (NIDDS):
TTS-fentanyl, EMLA, TMDS, intra-nasal, Pulm6. Implantable Neuraxial Delivery Devices (INDDS):
If pain occurs, there should be prompt oral administration of drugs in the following order: nonopioids (aspirin and paracetamol); then, as necessary, mild opioids (codeine); then strong
opioids such as morphine, until the patient is free of pain. To calm fears and anxiety, additional drugs – “adjuvants” – should be used. To maintain freedom from pain, drugs should be given “by
the clock”, that is every 3-6 hours, rather than “on demand” This three-step approach of administering the right drug in the right dose at the right time is inexpensive and 80-90%
effective. Surgical intervention on appropriate nerves may provide further pain relief if drugs are not wholly effective.
Modified WHO Analgesic Ladder
Proposed 4th Step
Pain
Step 1±Nonopioid± Adjuvant
Pain persisting or increasing
Step 2Opioid for mild to moderate pain
±Nonopioid ± Adjuvant
Pain persisting or increasing
Pain persisting or increasing
Step 3Opioid for moderate to severe pain
±Nonopioid ±Adjuvant
Invasive treatments
Opioid Delivery
Quality of Life
Deer, et al., 1999
Chronic Pain : OncogenicTreatment Modalities:
7. Neuro-stimulation-Lysis-Surgical/Anaesthesia/: tri-cyclics, anti-convulsants, TENS, Ketamine
8. Psycho Therapy & Counselling
9. Physio and Occupational Therapy
10. Miscellaneous: N/V, infections, Patho-fractures, constipation.....
CONCEPT OF PAIN CLINIC
PAIN CLINIC
Definition
The Care provided to the patients for the relief of Acute or Chronic pain of oncogenic as well as non-oncogenic origin on comprehensive, inter disciplinary and multi-dimensional basis by a team of experts with broad base of knowledge, and skills under one roof is called “multi-disciplinary approach to management of Pain” and such an establishment is called as pain Clinic.
PAIN CLINIC (CONTD.)
TEAMPhysicians : Anaesthesiologists Oncologists medical surgical radiationPsychologist/Behavioural TherapistPhysio/Occupational Therapist Nursing staffSocial Worker
CONCLUSIONPAIN
• Is all encompassing, everlasting & complex• Quest for MANAGEMENT is unending• Journey from non- existent /barbarism to
PCAs, CCIPs, TTSs, NIIDs or INDDs• From Opium, Hashish, alcohol, Mandragora &
herbs to Remifentanil, ropivacane.Must go on & on & on.........never-ending search.
..... For that avails
Valour or strength though matchless, quelled with pain
Which all subdues and makes remiss the hands
of mightiest? Sense of pleasure we may well
Spare out of life perhaps, and not repine
But live content – which is calmest life ;
But pain is the perfect misery, the worst
Of evils and excessive over turns
All patience.
John Milton - Paradise Lost
Book VI
Nociception
Transduction Transmission Modulation Perception