2. WHAT IS PAIN?
• In 1968 McCaffery defined pain as
“whatever the experiencing person says it
is, existing whenever he/she says it does”
• In 1979 IASP defined pain as “unpleasant
sensory and emotional experience
associated with actual or potential tissue
damage, or described in terms of such
damage.”
• Pain from poena ---> Latin means punishment.
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4. Receptors
There are no specialised receptors
Pain receptors are called nociceptors
A sensory receptor that is capable of transducing and encoding
noxious stimuli (actually or potentially tissue damaging stimuli)
Nociceptors are free nerve endings
Free nerve endings are distributed everywhere
both somatic and visceral tissues
except brain tissue and lung parenchyma
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5. Nerve pathways carrying pain signals to the
brain
• Pain signals enter the spinal cord
• First synapse is present in the dorsal horn of
the spinal cord
• Then the second order neuron travels through
the lateral spinothalamic tracts
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6. TYPES OF PAIN FIBRES
TYPE OF
NERVE
A- DELTA
C
CONDUCTION
VELOCITY
( MTS/SEC )
MELINATED
20 (fast)
YES
1 (slow)
No
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TYPE OF PAIN
SHARP,
PRICKING,WELL
LOCALIZED
DULL ACHE,
DIFFUSE
7. central connections
• afferent fibre enters the spinal cord
• synapses in laminae ii,iii
– substantia gelatinosa
substantia
gelatinosa
Neurotransmitter at the first synapse of the
pain pathway is substance P
• Acute pain : glutamate
• Chronic pain: substance P
• Pain inhibitory neurotransmitters: enkephalin, GABA
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8. ascending pathway
• crosses the midline
• ascends up as the lateral spinothalamic tract
Pain
C fibre
substantia
gelatinosa
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lateral
spinothalamic
tract
10. Pain perception
• This occurs at different levels
– thalamus is an important centre of pain
perception
• lesions of thalamus produces severe type of
pain known as ‘thalamic pain’
– Sensory cortex is necessary for the
localisation of pain
– Other areas are also important
• reticular formation, limbic areas,
hypothalamus and other subcortical areas
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12. Pathophysiology of pain
Pain sensations could arise due to
– Inflammation of the nerves (neuritis)
– Injury to the nerves and nerve endings with scar
formation (disc prolapse)
– Injury to the structures in the spinal cord, thalamus or
cortical areas that process pain information (spinal
trauma)
– Abnormal activity in the nerve circuits that is
perceived as pain (phantom limb pain)
– Nerve invasion, for example by cancer (brachial
plexopathy)
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13. PHYSIOLOGICAL EFFECTS
OF PAIN
Pulmonary
(Dec lung
volume)
Atelectasis
Ventilation perfusion mismatch
Arterial hypoxemia
Hypercarbia
pneumonia
CVS(SNS
Stim)
HTN
Tachycardia
Myocardial Ischemia
Cardiac Dysrhythmia
Endocrine
system
Hyperglycemia
Sodium & water retention
Protein catabolism
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14. PHYSIOLOGICAL
EFFECTS OF PAIN
Immune
system
Decreased immune function
Coagulation
system
Increased platelet adhesiveness
Decreased fibrinolysis
Hypercoagulation
DVT
GI system
Ileus
Genitourinary
system
Urinary retention
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15. ACUTE Vs CHRONIC
1. Nociceptive and has
Biologic function
1. No biologic value
2. Acts as warning and
indicates tissue injury
2. Detrimental effects
3. Recent onset & finite
duration-weeks to days
Illness or injury-months
3. Persists beyond acute
4. Remits when underlying
pathotlogy resolves
4. Chronic pathological
process & can recur
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17. PAIN CATEGORY
DEFINITION AND EXAMPLES
CHARACTERISTICS
Somatic
Pain resulting from injury to or
inflammation of tissues .
Examples: burns, lacerations,
fractures, infections,
inflammatory conditions
In skin and superficial structures:
sharp; pulsatile; well-localized
In deep somatic structures: dull;
aching; pulsatile; not welllocalized
Visceral
Pain resulting from injury to or
inflammation of viscera
Examples: angina, hepatitic
distention, bowel distention or
hypermobility, pancreatitis
Aching and cramping;
nonpulsatile; poorly localized
(e.g., appendiceal pain perceived
around umbilicus) or referred to
distant locations (e.g., angina
perceived in shoulder)
Neuropathic
Pain resulting from injury to,
inflammation of, or dysfunction
of the peripheral or central
nervous systems.
Examples: complex regional
pain syndrome (CRPS),
Spontaneous; burning; lancinating
or shooting ; pain may be
perceived distal or proximal to
site of injury, usually
corresponding to innervation
pathways (e.g., sciatica)
29. MEDICATION
DOSAGE
SIDE EFECTS
Acetaminophen
10-15 mg/kg PO q4h
20-30 mg/kg/PR q4h
Aspirin
10-15 mg/kg PO q4h
Anti-inflammatory; prolonged antiplatelet
effects; may cause gastritis; associated
with Reye's syndrome
Ibuprofen
8-10 mg/kg PO q6h
Anti-inflammatory; transient antiplatelet
effects; may cause gastritis; extensive
pediatric safety experience
Naprosyn
5-7 mg/kg PO q8-12h
Anti-inflammatory; transient antiplatelet
effects; may cause gastritis; more
prolonged duration than that of ibuprofen
Ketorolac
Loading dose 0.5 mg/kg,
then 0.25-0.3 mg/kg IV
q6h to a maximum of 5
days; maximum dose
30 mg loading with
maximum dosing of
15 mg q6h
Anti-inflammatory; reversible antiplatelet
effects; may cause gastritis; useful for
short-term situations in which oral dosing
is not feasible
n
Little anti-inflammatory action; no
antiplatelet or adverse gastric effects; can
produce fulminant hepatic failure
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33. Non-pharmacological therapy
• Relaxation techniques promote muscle relaxation and reduction of
anxiety, which often accompanies and increases pain. Controlled
breathing and progressive muscle relaxation are commonly used
relaxation techniques
• Distraction techniques- Focusing a child's attention away from something
negative to something more positive such as music, toys or bubbles
• Hypnosis helps a child focus on an imaginative experience that is
comforting, safe, fun.
• Biofeedback involves controlled breathing, relaxation, or hypnotic
techniques with a mechanical device that provides visual or auditory
feedback to the child when the desired action is approximated.
• Iyengar yoga was developed to achieve balance in mind, body, and spirit.
• Physical therapy can be especially useful for children with chronic,
musculoskeletal pain and for those deconditioned from inactivity.
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34. Non-pharmacological therapy
• Transcutaneous nerve electrical stimulation (TENS) refers to sending
small electric currents through the skin. It is a possible treatment for
neuropathic pain (in combination with opioids) but is not always effective.
It has few side-effects so is often trialed initially in patients with moderate
pain.
• Acupuncture involves the placement of needles at specific acupuncture
points along a meridian, or energy field, after a diagnosis of excess or
deficiency energy in that meridian as the primary cause of the pain is
made by the acupuncturist
•
Music and art therapy.
• Dance, movement, pet therapies, and aromatherapy
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35. INVASIVE INTERVENTIONS
• Neuraxial and peripheral nerve blocks provide
intraoperative anesthesia, postoperative analgesia
,treatment of acute pain and contribute to the
management of chronic pain
• Regional anesthesia
-It is an alternative to or augmentation of opioid-based pain
control, thereby minimizing the opioid side effects.
- It generally provides better quality pain stress responses;
- It results in earlier ambulation in recovering surgical
patients;
-It helps prevent atelectasis in the setting of severe chest pain;
-It usually results in earlier discharge from the hospital.
• Nerve ablation & destruction.
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37. Neonatal Pain Management
Minimally invasive procedures:
• Sucrose 0.5ml 24% sol p/o -2min before and just prior to
procedure along with non pharmacological strategies.
• Breast feeding.
• Topical Analgesia : EMLA( lidocaine+Prilocaine)
Invasive Procedures : Opioids
Post Operative Analgesia:
•
•
•
•
& sedatives
Pain history & previous opioid use.
Severity of procedure.
Post op airway management.
Post op desired level of sedation.
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38. Prior h/o opioid exposure
Major Sx Procedure
Prolonged intubation anticipated
All No
LOW DOSE PROTOCOL
1.I.P phase
Fentanyl/ Morphine -3doses
2. Cont. Phase
Fentany/Morphine infusion
Any Yes
HIGH DOSE PROTOCOL
1.I.P
Fentanyl/Morphine-3 dose
2. Cont. Phase
Fentanyl/Morphine
Adjunctive Therapy
Acetaminophen for 72 hrs
BDZ( Midaz bolus/ infusion)
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Weaning Protocol
39. Low dose protocol:
Evaluate at 24hrs after sx and then every 12hrs.
Pt extubated & pain well managed- cont .
Infusions stopped & managed with non
opioids.
High dose protocol:
Pt specific weaning plan should be developed.
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41. Advanced diseases: Neurodegenerative disorders,
AIDS , cancer –palliatve care for optimal QOL. Pharmacological
& non pharmacological therapy.
Recurrent Pain Syndromes: Neuropathic pain- Anti
Depressants-TCA & SSRI, AED (Gabapentin, Pregabalin,
Lamotrigine). Invasive interventions may be tried.
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