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Perioperative Pain Management


Acute Perioperative Pain Management Dr. Mahmoud Abdel-Khalek – PowerPoint PPT presentation

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Title: Perioperative Pain Management

Acute Perioperative Pain Management
Dr. Mahmoud Abdel-Khalek
What is pain?
  • An unpleasant sensory and emotional experience
    associated with actual or potential tissue
    damage, or described in terms of such damage
  • IASP Pain Definition (1994, 2008)
  • IASP International Association for the study of

Introduction Nociception
Introduction Nociception
  • Refers to the detection, transduction and
    transmission of noxious stimuli
  • Substances generated from thermal, mechanical or
    chemical tissue damage, activate free nerve
    endings, which we refer to as nociceptors
  • These afferent fibers have their cell body
    located in the dorsal root ganglion
  • From DRG axons go into dorsal horn of the spinal
    cord where axons synapse with the second order
    neuron as well as with regulatory interneuron.
    In addition synapses occur with the cell bodies
    of the sympathetic nervous system and ventral
    motor nuclei, either directly or through the
    internuncial neurons

  • The cell body of the second order neuron lies in
    the dorsal horn. Axonal projections of this
    neuron cross to the contralateral hemisphere of
    the spinal cord and ascend to the level of the
  • In the thalamus, the second order neuron synapses
    with a third order afferent neuron, which sends
    axonal projections into the sensory cortex

Postoperative Pain
  • Postoperative pain can be divided into acute pain
    and chronic pain
  • Acute pain is experienced immediately after
    surgery (up to 7 days)
  • Pain which lasts more than 3 months after the
    injury is considered to be chronic.

Why Treat Pain?
  • Basic human right!
  • ? pain and suffering
  • ? complications next slide
  • ? likelihood of chronic pain development
  • ? patient satisfaction
  • ? speed of recovery ? ? length of stay ? ? cost
  • ? productivity and quality of life

Adverse Effects of Poor Pain Control
  • CVS MI, dysrhythmias
  • Respiratory atelectasis, pneumonia
  • GI ileus, anastomotic failure
  • Endocrine stress hormones
  • Hypercoagulable state DVT, PE
  • Impaired immunological state
  • Infection, cancer, delayed wound healing
  • Psychological
  • Anxiety, Depression, Fatigue

  • Inadequately treated pain following chest
    abdominal incisions ? diaphragmatic muscle
    splinting ? ? ability to cough clear secretions
    ? atelectasis, hypoxemia pneumonia
  • Nociceptive stimuli reaching the spinal cord ?
    sympathetic stimulation ? hypertension,
    tachycardia ? ? heart work load ? ? oxygen demand
    ? myocardial ischemia in vulnerable patients
    myocardial infarction

  • Also increased sympathetic tone ? ? intestinal
    secretions slows gut motility ? smooth muscle
    tone ? gastric stasis, nausea and vomiting, ileus
    and urinary retention
  • Poorly controlled acute pain ? initiation and
    maintenance of stress response seen with the
    trauma of major surgery ? hypercoagulability ?
    DVT, p. embolism, MI, ? immunity,
    hypermetabolism, Hyperglycemia, protein
    catabolism and delayed wound healing

Pain Assessment
  • Pain History
  • O Onset
  • P Provoking / Palliating factors
  • Q Quality / Quantity
  • R Radiation
  • S Severity
  • T Timing

Pain Assessment Severity Visual Analogue Scale
Severity of postoperative pain
Pain Assessment
  • Current Pain Medications
  • Accuracy and detail are very important Name,
    dose, frequency, route i.e. Oxycontin 10mg PO
  • Co-existing conditions
  • Renal disease avoid morphine, NSAIDs
  • Vomiting avoid oral forms of medication
  • Drug allergies
  • Document drug, adverse reaction and severity
  • Intolerances
  • Nausea / vomiting, hallucinations,
    disorientation, etc.

Methods to Treat Pain
  • Pharmacologic
  • Medications (po, iv, im, sc, pr, transdermal)
  • Acetaminophen
  • NSAIDs e.g. Aspirin, diclofenac, ibuprofen.. etc.
  • Opioids e.g. Morphine, pethidine, fentanyl,
    codeine.. etc.
  • Gabapentin
  • NMDA antagonists e.g. ketamine
  • Alpha-2 agonists
  • Procedures
  • Regional Anesthesia
  • LA infiltration at incision site
  • Surgical Intervention
  • Removal of cause of pain e.g. distended urinary

WHO Analgesic Ladder
Acetaminophen (aka Paracetamol)
  • First-line treatment if no contraindication
  • It is relatively safe
  • It is analgesic and antipyretic
  • Mechanism thought to inhibit prostaglandin
    synthesis in CNS ? analgesia, antipyretic
  • It does not cause gastric irritation
  • Typical dose 650 to 1000 mg PO Q6H
  • Max dose 4 g / 24 hrs from all sources
  • Warning ? dose / avoid in those with liver

  • Also, first-line treatment
  • Mechanism
  • Block cyclooxygenase (COX) enzyme ? ?
    prostaglandin synthesis
  • COX-2 ? Prostaglandins ? pain, inflammation,
  • COX-1 ? Prostaglandins ? gastric protection,

  • Warnings ?dose / avoid if
  • GI ulceration
  • Bleeding disorders / Coagulopathy
  • Renal dysfunction
  • Asthma
  • Allergy

  • They are highly effective class of analgesics
    which operates at several levels in the nervous
  • Intramuscular morphine or meperidine on prn basis
    remains the most popular form of acute
    postoperative pain management at most hospitals

Opioids mechanism of action
  • They dampen the transmission of nociceptive
    stimuli by binding to opioid receptors within
    substantia gelationsa of the dorsal horn of
    spinal cord
  • They release inhibitory neurotransmitters such as
    noradrenaline, serotonin and GABA
  • Decrease inflammatory response in the periphery
  • Affect mood and anxiety

Intramuscular opioid administration limitations
  • Responsibility for management of pain is
    delegated to the nursing staff, who err on the
    side of caution in the administration of opioids.
    They tend to give too small a dose of drug too
    infrequently because of exaggerated fears of
    producing ventilatory depression or addiction.
  • Because the administration of drugs is left
    entirely to the discretion of the nursing staff,
    the degree of empathy between nurse and patient
    affects analgesic administration.
  • Because the measurement of pain is difficult, it
    is seldom possible to adjust the dose of drug to
    match the extent of pain.
  • There are enormous variations in the extent of
    analgesic requirements depending upon the type of
    surgery, pharmacokinetic variability
    pharmacodynamic variability, etc.

Opioids Side effects
  • Nausea / Vomiting
  • Sedation
  • Respiratory Depression
  • Pruritus
  • Constipation
  • Urinary Retention
  • Ileus
  • Tolerance

  • Morphine
  • Most commonly prescribed opioid in hospital
  • Metabolism
  • Conjugation with glucuronic acid in liver and
  • Morphine-3-glucuronide (inactive)
  • Morphine-6-glucuronide (active)
  • Impaired morphine glucuronide elimination in
    renal failure
  • Prolonged respiratory depression with small doses
  • Due to metabolite build-up (morphine-6-glucuronide

  • Hydromorphone (Dilaudid)
  • Better tolerated by elderly, better S/E profile
  • Preferred over morphine for renal disease
  • Low cost, IV and PO forms available
  • Oxycodone
  • Good S/E profile, but
  • PO form only
  • Percocet (oxycodone acetaminophen)

  • Codeine
  • 1/10th Potency of morphine
  • Metabolized into morphine by body
  • Ineffective in 10 of Caucasian patents
  • Challenge with combination formulations
  • Meperidine (Demerol)
  • Not very potent
  • Decreases seizure threshold, dystonic reactions
  • Neurotoxic metabolite (normeperidine)
  • Avoid in renal disease

Opioids - Formulations
  • Short acting forms
  • Need to be dosed frequently to maintain
    consistent analgesia
  • Controlled Release forms
  • Provides more consistent steady state level
  • Helpful for severe pain or chronic pain
  • Never crush / split / chew controlled release

Management of Opioid Overdose
  • Ddx
  • Seizure, stroke
  • Hypoxia, Hypercarbia
  • Hypotension
  • Other medication effect
  • Severe electrolyte or acid base abnormalities
  • MI
  • Sepsis
  • ..etc.

Management of Opioid Overdose
  • For ?level of consciousness, somnolent patient
  • Stimulate patient
  • Vitals/Monitors/Lines
  • Airway
  • Breathing
  • Circulation

Management of Opioid Overdose
  • Opioid Reversal
  • Naloxone - opioid antagonist
  • Reverses effects of opioid overdose (for
  • MUST BE diluted before use
  • 0.4mg ampule
  • Dilute 1mL Naloxone 9mL Saline 0.04 mg/mL
  • Give 0.04 to 0.08 mg (1 to 2 mL) IV q3-5 minutes
  • If no change after 0.2mg, consider other causes

Opioids PCA
  • Patient-controlled analgesia (PCA) permits the
    patient to administer the delivery of his own
    analgesic by activating a button, which then
    triggers the intravenous delivery of a
    predetermined dose of an opioid such as morphine.
  • Limits are set on the number of doses per
    four-hour period and on the minimum time that
    must elapse between doses (lockout interval).
  • The pharmacokinetic advantage of PCA is that by
    self administering frequent, small doses, the
    patient is able to come closer to achieving a
    steady state analgesic level in the blood,
    avoiding the high peaks and low troughs that can
    be found with intermittent (intramuscular) opioid

Benefits of PCA
  • PCA has been shown to provide equivalent
    analgesia with less total drug dose, less
    sedation, fewer nocturnal disturbances and more
    rapid return to physical activity.
  • In addition, patient acceptance is high since
    patients have a significant level of control over
    their pain management.
  • PCA analgesia is not without side effects, the
    most common of which is nausea and vomiting,
    Excessive sedation and pruritus
  • Standardized orders provide as needed orders
    for medications to counteract both nausea and

Benefits of PCA
  • Although it does not obviate the need for close
    monitoring, PCA frees nursing personnel from
    administering analgesic medication.
  • Since patients titrate their own therapy with
    PCA, they must be capable of understanding the
    principle, willing to participate and physically
    able to activate the trigger. Consequently, use
    is prohibited at the extremes of age as well as
    in very ill or debilitated patients
  • Typically, the PCA modality is used for 24-72
  • The patient must be capable of oral (fluid)
    intake prior to converting from PCA to oral

Opioids PCA
Management of Opioid Side Effects
  • Nausea / Vomiting
  • Ondansetron (Zofran)
  • Dimenhydrinate (Gravol)
  • Metoclopramide (Maxeran)
  • Changing medication(s) / ? dose
  • Pruritus
  • Diphenhydramine (Benadryl)
  • Changing medication(s) / ? dose

  • Anti-epileptic drug, also useful in
  • Neuropathic pain, Postherpetic neuralgia, CRPS
  • Blocks voltage-gated Ca channels in CNS
  • Additive effect with NSAIDs
  • Reduces opioid consumption by 16-67
  • Reduces opioid related side effects
  • Drowsiness if dose increased too fast

Regional Anesthesia
  • Involves blockade of nerve impulses using local
    anesthetics (LA)
  • LA bind sodium channels preventing propagation of
    action potentials along nerves
  • Wide variety of LA with different
  • i.e. Lidocaine fast onset, short duration of
  • i.e. Bupivacaine (Marcaine) slow onset, longer

Central neuraxial analgesia
  • Central neuraxial analgesia involves the delivery
    of local anesthetics and/or opioids to either the
    intrathecal (spinal) space or the epidural space.
  • Opioids added to the (spinal) local anesthetic
    solution provide long-lasting analgesia after a
    single injection, lasting well into the
    post-operative period
  • The duration of effect is directly proportional
    to the water-solubility of the compound, with
    hydrophilic compounds such as morphine providing
    the longest relief
  • Epidural catheters are safe and easy to insert

Epidural Analgesia
  • Epidural analgesia can be used to provide pain
    relief for days through the infusion of a
    solution containing local anesthetic, opioid or
    both. The infusion is usually delivered
  • Continuous epidural infusions provide a steady
    level of analgesia while reducing the
    side-effects associated with bolus administration
  • Overall, epidural analgesia can provide highly
    effective management of post-operative pain

Benefits of Epidural Analgesia
  • Superior analgesia to IV, PCA in open abdominal
    procedures specifically in colorectal surgery
  • Reduce incidence of paralytic ileus
  • Blunt surgical stress response
  • Improves dynamic pain relief
  • Reduces systemic opiate requirements

Regional Anesthesia
  • Peripheral Nerve Blocks
  • Upper Limb Brachial plexus
  • Lower Limb Femoral, sciatic, popliteal, ankle
  • Abdomen TAP blocks
  • Thoracic Paravertebral, intercostal blocks
  • Use of Ultrasound Imaging has revolutionized
    peripheral nerve blockade
  • Safety?
  • Accuracy / Improved Success
  • Efficiency

Contraindications to Neuraxial Blockade
  • Absolute
  • Pt refusal or allergy to LA
  • Uncorrected hypovolemia
  • Infection at insertion site
  • Raised ICP
  • Coagulopathy
  • Relative
  • Uncooperative patient
  • Fixed cardiac output states
  • Systemic infection/sepsis
  • Unstable neurological disease
  • Significant spine abnormalities or surgery

Peripheral Nerve Blocks
  • Almost any peripheral nerve that can be reached
    with a needle can be blocked with local
  • The brachial plexus, intercostal and femoral
    nerves are examples of nerves which are commonly
    blocked to provide post-operative analgesia
  • A block may be used as the sole method of
    post-operative analgesia or it may be useful as
    an adjunct to decrease the required dose of
    systemic opioids
  • The major drawback of this method of
    post-operative analgesia is that the duration of
    effect of a single block is limited, usually to
    less than 18 hours
  • A typical example of the use of a peripheral
    nerve block for post-operative pain would be the
    use of a femoral/sciatic nerve block for a
    patient undergoing total knee arthroplasty. The
    block would be augmented with oral opioids and
    other adjuncts

  • Accurate pain assessment
  • Use Multimodal pain management
  • Superior analgesia, ? side effects means
  • Improved patient satisfaction
  • Better rehabilitation
  • Earlier functional return
  • Earlier discharge from hospital
  • ? likelihood of chronic pain
  • Reduced health care costs

Thank you
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