Moderator : Dr Alok Basu Roy

Presenter: Dr Saurabh Kakkar

Postoperative pain, especially when poorly

controlled, results in harmful acute effects and chronic effects

Widespread recognition of the under treatment of acute pain by clinicians, economists, and health policy experts has led to the development of a national clinical practice guideline for management of acute pain by a agency of U.S.

Introduction

Anesthesiologists have developed the concept of acute postoperative pain services application of evidence based practice to acute postoperative pain, and creation of innovative approaches to acute pain medicine

Anesthesiologists functions as a “perioperative physician” consultant, and therapist throughout an institution, as well as a highly skilled expert in the operating room

Postoperative pain management should be tailored to the needs of special populations who may have different anatomic, physiologic, pharmacologic, or psychosocial issues

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Surgery produces tissue injury with consequent

release of histamine and inflammatory mediators

Release of inflammatory mediators activates peripheral nociceptors, which initiate transduction and transmission of nociceptive information to the central nervous system

Noxious stimuli are transduced by peripheral nociceptors and transmitted by A-delta and C nerve fibers from peripheral visceral and somatic sites to the dorsal horn of the spinal cord, where integration of peripheral nociceptive and descending modulatory input occurs

Pain pathway

Some impulses pass to the ventral and ventrolateral horns to initiate segmental (spinal) reflex responses, which may be associated with increased skeletal muscle tone, inhibition of phrenic nerve function, or even decreased gastrointestinal motility

Others are transmitted to higher centers through the spinothalamic and spinoreticular tracts, where they induce supra segmental and cortical responses to ultimately produce the perception of and affective component of pain

Continuous release of inflammatory mediators causes Sensitization of peripheral nociceptors may occur and is marked by a decreased threshold for activation, increased rate of discharge with activation, and increased rate of basal discharge

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Intense noxious input from the periphery may also result in central sensitization ( hypersensitivity) and hyperexcitability.

Nociception is a dynamic process (i.e., neuroplasticity) with multiple points of modulation.

Persistent noxious input may result in relatively rapid neuronal sensitization and possibly persistent pain

The intensity of acute postoperative pain is a significant predictor of chronic postoperative pain

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Patient dis-satisfaction

Decreased Respiratory function

Myocardial ischemia

Sodium and water retention

Increased catabolic state

Postoperative hypercoagulable state

Immunosuppression

Poor wound healing

Prolonged paralytic ileus

Acute effects of postoperative pain

Delayed recovery

Inability to participate in rehabilitation

Chronic postsurgical pain ( CPSP )

Financial expenses

Chronic effects of postoperative pain

Previously called “ preemptive analgesia ”

It refers to an analgesic intervention that preceded a surgical injury and was more effective in relieving acute postoperative pain than the same treatment following surgery

The rationale for preemptive analgesia was based on the inhibition of the development of central sensitization

An intervention administered before the surgical incision is not preventative if it is incomplete or insufficient

Preventive Analgesia

Principles of a multimodal strategy include:

Control of postoperative pain to allow early mobilization

early enteral nutrition

education, and attenuation of the perioperative stress response through the use of regional anesthetic techniques

combination of analgesic drugs (i.e., multimodal analgesia)

The multimodal approach integrates the most recent data and techniques from surgery, anesthesiology, nociceptive neurobiology, and pain treatment, making it an extension of clinical pathways (Enhanced Recovery After Surgery, or ERAS) or fast tracks

MULTIMODAL APPROACH TO

PERIOPERATIVE RECOVERY

Systemic

1. Opioid analgesics

2. Non-opioid analgesics

Regional

1. Neuraxial techniques

2. Peripheral techniques

Treatment Methods

Cornerstone for postoperative pain treatment

Opioids may be administered by the subcutaneous, transcutaneous, transmucosal, or intramuscular route, oral and intravenous

Prescribed on an as-needed (PRN) basis

Intravenous Patient-Controlled Analgesia (PCA)

Opioids

PCA optimizes delivery of analgesic opioids and

minimizes the effects of pharmacokinetic and pharmacodynamic variability in individual patients

When pain is experienced, analgesic medication is self-administered, and when pain is reduced

PCA device can be programmed for several variables, including the demand (bolus) dose, lockout interval, and background infusion

Intravenous Patient-Controlled

Analgesia

NSAID’S :

Inhibition of cyclooxygenase (COX) and synthesis of prostaglandins

COX-1 is constitutive and COX-2 is inducible

COX-1 participates in platelet aggregation, hemostasis, and gastric mucosal protection, whereas COX-2 participates in pain, inflammation, and fever

provide effective analgesia for mild to moderate pain

side effects include decreased hemostasis, renal dysfunction, and gastrointestinal hemorrhage

Diclofenac, Acetaminophen , Ketorolac

Non - Opioids

Gabapentanoids Gabapentin and pregabalin, antiepileptic drugs

used in the treatment of neuropathic pain

interact with calcium channel α2-δ ligands to inhibit calcium influx and subsequent release of excitatory neurotransmitters

meta-analysis demonstrated use of pregabalin was associated with a decrease in opioid consumption and opioid-related side effects, but no difference in pain intensity

perioperative administration of gabapentin and pregabalin may reduce the incidence of CPSP

Non - Opioids

Ketamine

Traditionally recognized as an intraoperatively anesthetic induction agent

Small analgesic dose ketamine can facilitate postoperative analgesia because of its NMDA-antagonistic properties, which may be important in attenuating central sensitization and opioid tolerance

can be administered orally, intravenously, subcutaneously, or intramuscularly

Non - Opioids

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Single-Dose Neuraxial Opioids

Administration of a single dose of opioid may be efficacious as a sole or adjuvant analgesic drug when administered intrathecally or epidurally

One of the most important factors in determining the clinical pharmacology for a particular opioid is its degree of lipophilicity

Continuous Epidural Analgesia

Analgesia delivered through an indwelling epidural catheter is a safe and effective method for management of acute postoperative pain

REGIONAL ANALGESIC TECHNIQUES

DRUG INTRATHECAL

SINGLE DOSE EPIDURAL SINGLE DOSE

EPIDURAL CONTINUOUS INFUSION

FENTANYL 5 – 25 µg 50 – 100 µg 25 – 100 µg/hr

MORPHINE 0.1 – 0.3 µg 1 – 5 µg 0.1 – 0.2 µg/hr

REGIONAL ANALGESIC TECHNIQUES

Local anesthetics

Opioids

Local anesthetics + Opioids

Adjuvants – Clonidine , Ketamine , Dexmedtomidine

Analgesic drugs for regional

techniques

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Hypotension

Motor block

Pruritus

Respiratory depression

Nausea and vomiting

Urinary retention

Migration of catheter

Side Effects of Neuraxial Analgesic

Drugs

Patient Controlled Epidural Analgesia

Reduction in mortality and morbidity

Postoperative thoracic epidural analgesia can facilitate return of gastrointestinal motility without contributing to anastomotic bowel dehiscence

Preserving postoperative pulmonary function through providing superior analgesia and thus reducing splinting behavior and attenuating the spinal reflex inhibition of diaphragmatic function

Decreases the incidence of postoperative myocardial infarction by attenuating the stress response and hypercoagulability

Benefits of Epidural Analgesia

Epidural hematoma

Epidural abscess

Infections like meningitis

Intrathecal or intravascular migration

Risks With Epidural Analgesia

Analgesia superior to that with systemic opioids

Brachial plexus, Lumbar plexus, Femoral, Sciatic-popliteal, and Scalp nerve blocks

one-time injection used primarily for intraoperative anesthesia

Continuous infusions of local anesthetics is administered through peripheral nerve catheters

Techniques like nerve stimulation, ultrasound guidance, and paresthesia elicitation are used

Peripheral Regional Analgesia

Paravertebral blocks

Intercostal blocks

Transversus abdominis plane blocks

Interpleural (intrapleural) analgesia

Cryoanalgesia

Intra – articular analgesia

Nonepidural Analgesia

Transcutaneous electrical nerve stimulation (TENS)

Acupuncture

Exercise/activity

Psychological approaches

All of these approaches to postoperative pain are relatively safe, noninvasive, and devoid of the systemic side effects seen with other analgesic treatment options

Non – Pharmacological techniques

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