MULTIMODAL PAIN MANAGEMENT IN ORTHOPAEDIC PROCEDURES

Presenter - Dr.V.S.Yamini

Moderator – Dr. J.BalaVenkat

Objectives Concept of nociception

Central sensitisation

Multimodal analgesia for perioperative pain management

ASRA 2016 GUIDELINES on Pain management

Consequences of Inadequate Postoperative pain Relief

Definition of Pain IASP - An unpleasant sensory and emotional

experience associated with actual or potential tissue damage, or described in terms of such damage.

Latin – Poena – Pain

More than 80% of patients who undergo surgical procedures experience acute postoperative pain

And approximately 75% of those with postoperative pain report the severity as moderate, severe, or extreme

CLASSIFICATION OF PAIN

PAIN

SOMATIC

SUPERFICIAL( Skin n subcut tissues )Eg: Cuts, Burns

DEEP( Muscle, Bone, Periosteum,

Fascia )Eg :Fractures, Arthritis,

Muscle belly rupture

VISCERALEg : Angina pectoris,

Renal colic, Intestinal colic

PAIN RECEPTORSAre sensory receptors and cutaneous receptors and pain receptors the same ???

Sensory receptors - Sensory input from various external stimuli is thought to be received by specific peripheral receptors that act as transducers and transmit by nerve action potentials along specific nerve pathways to CNS.

First order afferents – differentially sensitive

CUTANEOUS RECEPTORS Mechanoreceptors Tactile non painful stimuli Pacinian , Meissner corpuscle, Merkel’s disc 2 point discrimination, proprioception

Thermoreceptors

Nociceptors Free Nerve ending that responds to a noxious stimulus

NOCICEPTION Nociceptor- A high-threshold sensory receptor of the peripheral

somatosensory nervous system that is capable of transducing and encoding noxious stimuli.

Nociception begins in the nerve terminals of sensory neurons

Mechanical, Chemical or thermal

Polymodal

Silent Nociceptors

Types of Nociceptors :

Aδ Unmyelinated C fibers

Receptor Types

ION CHANNELS

Neurochemistry1. TRP ( Transient receptor potential ) channels A. Temperature : TRPV1 >42°C TRPA1 <17°C

B.Chemical : TRPV1 – Capsaicin , Piperine TRPA2- Cinnamaldehyde

C. Inflammatory signals: Bradykinin, NGF ( TRPV1)

D. Itch signals : Histamine (TRPV1)

E. Mechanosensors : TRPV4

F. Acid sensing : TRPV1 Ph 5.5

2.ACID SENSING ION CHANNELS eNac family – ph 6.5 to 6.9 Asic3 – Angina

3. PURINOCEPTORS Neuropathic pain

4. TWO PORE DOMAIN POTASSIUM CHANNEL

5. Voltage Gated Sodium Channel

NEURAL PAIN PATHWAY

° TRANSDUCTION Chemical events to Electrical events in neurons

º TRANSMISSION Electrical events are transmitted Molecules in the synaptic cleft transmit information from one cell surface to another .

ºMODULATION Up regulation or Down Regulation

ºPERCEPTION

The Substantia Gelotinosa Rolandi– tip of dorsal horn – Called Gate

NEUROTRANSMITTER – A delta – Glutamate C fibers – Substance P

Key role in pain perception

A Delta – Fast – Terminate at lamina I – Neospinothalamic

C – Slow – Lamina II &III of dorsal horn – SG -Paleospinothalamic

NORMAL SENSATION

CENTRAL SENSITISATION

THE CONCEPT OF MULTIMODAL ANALGESIA

MULTIMODAL ANALGESIA

Multimodal analgesia is achieved by combining different analgesics that act by different mechanisms and at different sites in the nervous system, resulting in additive or synergistic analgesia with lowered adverse effects of sole administration of individual analgesics

These regimens must be tailored to individual patients, keeping in mind the procedure being performed, side effects of individual medications and patients’ pre-existing medical conditions.

Pain pathways and multimodal analgesic pathways

1.NSAIDS AND COX2 INHIBITORS PG E2 – Causes reduced pain threshold or incites

an inflammatory response at the site of injury

NSAIDS inhibit the synthesis of prostaglandins both in the periphery and spinal cord thus diminishing the hyperalgesic states.

Only iv NSAID - Ketorolac Also available as intra nasal Latest – iv Ibuprofen Topical 1% Diclofenac

2.ACETAMINOPHEN

3.ANTI CONVULSANTS Inhibit the central neuronal sensitisation

Pregabalin and Gabapentin

Alpha-2-delta subunit of N-type voltage-gated calcium channels in DRG and brain

Reduction in the release of neurotransmitters such as glutamate and substance P

4.NMDA RECEPTOR ANTAGONISTS

Ketamine – iv or intra nasal Memantine – Oral . Completely absorbed

from GIT, Approx 80% remains as parent drug. Usual dose – 10 mg bd with 5-10 mg / day increments

Magnesium –inhibition of calcium influx , Antagonism of NMDA receptors

5. ALPHA 2 AGONISTS The alpha-2 adrenergic receptor has high

density in the substantia gelatinosa of the dorsal horn in humans and that is believed to be the primary site of action by which alpha-2 adrenergic agonists can reduce pain.

Dexmeditimidine and Clonidine

6. TAPENTADOL Mu opioid receptor agonism Noradrenaline reuptake inhibitor

100 mg tapentadol = 15 mg oxycodone

Decreased incidence of nausea and vomiting for equipotent doses of opioids

7.SPINAL AND EPIDURAL ANALGESIA

Sensory and motor block

Local anaesthetics plus adjuvants

NEWER AND EMERGING TECHNOLOGIES IN PAIN MANAGEMENT

8. PERIPHERAL Nerve block

9. Transdermal fentanyl

10. Extended release epidural Morphine

11. Liposomal Bupivacaine

12. Patient controlled analgesia

Tailored education to patient or responsible caregiver

Parents of children should receive instruction in methods of assessing pain and appropriate administration of analgesics

History of medical and psychiatric comorbidities, substance abuse ,chronic pain

Adjust the pain management plan based on adequacy of pain relief and presence of adverse events

Validated pain assessment tool to track responses

NEED FOR EFFECTIVE PATIENT EDUCATION

Dr House asthma inhaler.mp4

Multimodal analgesia - Combination of pharmacological and non pharmacological techniques

Oral opioids preferred over i.v. opioids for post operative analgesia

Avoid intramuscular route of drug administration

I.V. PCA to be used for post op systemic analgesia

No basal continuous iv infusion of opioids

Appropriate monitoring of sedation, respiratory sedation in patients receiving iv opioids

Acetaminophen and /or NSAIDS as a part of multimodal analgesia

200-400mg of celecoxib oral preop

Gabapentin or Pregaba as a component of multimodal analgesia

Use of topical local anaesthetics before giving peripheral nerve blocks

No intrapleural analgesia for pain control after thoracic surgery

Surgical site specific peripheral regional anesthesia technique

Continuous local anesthetic based peripheral regional anesthetic techniques

Neuraxial analgesia for major thoracic and abdominal procedures

Avoid neuraxial administration of magnesium, benzodiazepines, neostigmine, tramadol and ketamine

Organisational structures and policies and procedures to be developed and maintained

Clinicians should have access with consultation to a pain specialist in case of inadequately controlled post op pain

CONSEQUENCES OF INADEQUATE PAIN TREATMENT ORGAN SYSTEMS PHYSIOLOGICAL RESPONSE

1. CVS Increase in HR, PVR, SBP, Myocardial contractility, Increase oxygen demand

2. RS Respiratory muscle splintingDecreased vital capacityImpaired ventilationAtelectasisIncreased V/Q mismatch, Hypoventilation, Hypoxia, HypercarbiaIncreased pulmonary infection

3. GASTROINTESTINAL Increased anal sphincter toneDecreased intestinal motilityIleusNausea and vomiting

4.RENAL Increased urine sphincter tone Urine retention

5. COAGULATION Increased platelet aggregationVenostasisIncreased DVTThromboembolism

6.MUSCULAR Muscle weaknessLimitation of movementsMuscle atrophyFatigue

7.PSYCHOLOGICAL AnxietyFearDepression

8.OVERALL RECOVERY DelayedProlonged hospital stayDelayed return to normal life

PERSISTENT POST OPERATIVE PAIN CRITERIA FOR DIAGNOSIS 1. Pain developed after surgical procedure 2. Pain of atleast 2 months duration 3. Other causes of pain excluded

ACUTE TO PERSISTENT PAIN Peripheral and central sensitisation of nervous system

causes intractable pain that can become chronic

Repeated noxious stimuli can induce change in chemical profile , function or even structure of neurons – increased sensitivity to pain

Periph sensitisation – hyperexcitability of dorsal horn neurons

Central sensitisation – Hyperexcitability of spinal nociceptive neurons , expansion of sensory receptive fields , alterations in processing of innocuous stimuli

SUMMARY OF INTERVENTIONS FOR MANAGEMENT OF PAIN

1.NON PHARMACOLOGICAL a. Transcutaneous electric nerve stimulation b. Cognitive modalities2.SYSTEMIC PHARMACOLOGICAL a. Acetaminophen b. NSAIDS c. Oral Opioids d. Patient controlled i.v. analgesia with opioids e. Gabapentin and Pregabalin

2.SYSTEMIC PHARMACOLOGICAL

e. Ketamine i.v

f. Lignocaine i.v.

g.Local anesthetic infiltration

h.Intra articular local anesthetic

i. Topical local anaesthetics

J.Peripheral regional anesthetic techniques

K. Neuraxial analgesia

THANK YOU