Acute Pain
Management
Objectives/Discussion Topics
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Appropriate assessment of acute pain
Concept of multi-modal analgesia
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How to rationally prescribe opioids
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Indications and side effects of analgesics
side effects and complications of opioids
Special populations ie elderly, opioid tolerant
Neuraxial/regional analgesia
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side effects and complications of neuraxial analgesia
interaction of various anticoagulant medications and
neuraxial analgesia
Goal
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To provide patients with a level of pain control that
allows them to actively participate in recovery
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This level will be individual to each patient
To minimize nausea and vomiting
To minimize other side effects of analgesics
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Sedation
Ileus
Weakness
Hypotension
Why all the fuss?
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Pain is a miserable experience
Pain increases sympathetic output
Increases myocardial oxygen demand
 Increases BP, HR
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Pain limits mobility
Increases risk for DVT/PE
 Increases risk for pneumonia, atelectasis secondary
to splinting
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Assessment
Intensity
 Location
 Onset
 Duration
 Radiation
 Exacerbation
 Alleviation
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How do we do it?
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Multimodal analgesia: Several analgesics with different
mechanisms of action, each working at different sites in the
nervous system
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Acetaminophen
Non-steroidal anti-inflammatory drugs (NSAIDs)
Opioids
Anticonvulsants
Antidepressants
Local anaesthetics
NMDA Antagonists
Non-pharmacologic methods
OPIOIDS
Efficacy is limited by Side-Effects
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The harder we “push” with single mode analgesia, the greater
the degree of side-effects
Side-effects
Analgesia
Multimodal Analgesia
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Lower doses of each drug can be used therefore minimizing
side effects
With the multimodal analgesic approach there is additive
or even synergistic analgesia, while the side-effects profiles
are different and of small degree (Pasero & Stannard, 2012).
Side-effects
Analgesia
Systemic Analgesia
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Opioids
Potent analgesics
 Drug of choice for moderate to severe pain
 Unfortunately, they are often the only drug ordered
 Side effects:
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Opioids
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10 fold variability between patients
All opioids have same side effects but
efficacy:side effect ratio is different for everyone
Stick with what works and keep it simple
Always by mouth if possible
Avoid pro-drugs ie. codeine
Avoid combo preparations
Equianalgesia
Opioid
PO
Morphine
10 mg
Codeine
~ 60-100mg (4fold variability)
2 mg
5 mg
Hydromorphone
Oxycodone
Parenteral
(IV/SC)
5 mg
N/A
1 mg
N/A
NALOXONE (Narcan)
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Mu opioid antagonist
Dilute 1 mL of naloxone 0.4 mg/mL (ie. one
vial) with 9 mL of NS for a total of 10 mL of
solution and a final concentration of
0.04 mg/mL
Administer 0.04 mg at a time until reversal of
respiratory depression has been achieved, ie.
when they’re sitting up awake and talking to you!
NALOXONE (Narcan)
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REMEMBER: the half-life of naloxone is only
30 minutes, while the half-life of opioid is 2-3 hr
so you may have to repeat dosing OR place pt
on naloxone infusion until all opioid has been
metabolized to prevent further respiratory
depression
Elderly Patient
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Pronounced effect therefore, lower doses
Cognitive dysfunction is a major issue
Organ dysfunction/insufficiency affects
metabolism
Interaction with other medications, increased
incidence of polypharmacy
Addiction
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Primary, chronic, neurobiologic disease, with
genetic, psychosocial, and environmental factors
influencing its development and manifestations.
Characterized by behaviors that include one or
more of the following:
impaired control over drug use
 compulsive use
 continued use despite harm
 craving
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Definitions Related to the Use of Opioids for the Treatment of Pain. American Academy
of Pain Medicine; American Pain Society; American Society of Addiction Medicine. 2001.
Physical Dependence
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State of adaptation that is manifested by a drug
class-specific withdrawal syndrome that can be
produced by abrupt cessation, rapid dose
reduction, decreasing blood level of the drug,
and/or administration of an antagonist
Tolerance
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The body's physical adaptation to a drug:
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Greater amounts of the drug are required over time
to achieve the initial effect as the body adapts to the
intake
Pseudo Addiction
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Term used to describe patient behaviors that
may occur when pain is undertreated
May become focused on obtaining medications,
"clock watch," seem inappropriately "drug
seeking."
Illicit drug use and deception can occur in the
patient's efforts to obtain relief
Distinguished from true addiction in that the
behaviors resolve when pain is effectively
treated.
NSAIDS
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Work at site of tissue injury to prevent the
formation of the nociceptive mediators
Prostaglandins
Can decrease opioid use ~30% therefore
decreasing opioid-related side effects
Minor surgeries can use NSAIDs instead of
opioids to completely eliminate opioidassociated side effects
Side effects:
NSAIDS
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Newer NSAIDS selectively (primarily) inhibit
cyclooxygenase-2 (COX-2) which is induced by
surgical trauma with minimal effect on COX-1
which is responsible for GI and platelet side
effects
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Celecoxib (Celebrex)
Neuraxial Techniques
Who Gets Them?
Patient factors:
Low pain tolerance, opioid tolerance
 Sleep apnea
 Narcolepsy
 Obesity
 COPD
 Cardiac disease
 Elderly – those at risk for post-operative cognitive
dysfunction
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…….
Epidural Infusions
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Used for major surgery ie. oncologic TAH BSO,
thoracotomy
Ideally placed pre-operatively and used in
combination with a GA for surgery and
continued ~ 2 days
Usually patient is tolerating diet and ambulation
to chair when epidural is D/C
Ideal Epidural Infusions
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When placed at the level of the incision and with a constant
infusion of LA and opioid:
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Minimal or no pain at all, particularly with movement
No motor block
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Speedier return of bowel function
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Can ambulate
With more LA and less opioid –Cochrane review 2003
Less nausea
Less sedation
Less delerium
Do not require supplemental IV opioids and associated side effects
Less pulmonary complications
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Quicker extubation, better oxygen saturation, less pneumonia
Side Effects of Epidural Infusions
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Hypotension
LA causes a sympathectomy which leads to
vasodilatation
 Mild volume depletion, which can normally be
compensated for with vasoconstriction, will be
unmasked with an epidural
 Pts require adequate volume status with an epidural
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Side Effects
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Hypotension
Pts will initially c/o dizzyness, lightheadedness and
nausea when sitting up or standing
 Can document orthostatic hypotension
 Will then progress to supine hypotension if not
corrected
 Major problem POD #1 when 3rd spacing still
occurring, minimal IV fluids infusing and pt NPO
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Side Effects
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Leg weakness or numbness
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Can occur if catheter is too low (low thoracic or lumbar) or if
it is one-sided
Inhibits ambulation and distressing to pt therefore must be
fixed
Infusion can be adjusted or catheter pulled back
Must be addressed as this is the first sign of epidural
hematoma leading to permanent paralysis
Complications
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Post dural puncture headache 1:100
Only if dura is unintentionally punctured
 More likely in younger people
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Infection
Some reports of epidural abscess as high as 1:1900
 Usually just superficial skin infections
 Increased risk in immunosuppressed
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Complications
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Epidural hematoma
Most feared complication
 Incidence of 1:180 000 – 1:220 000
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Increased with heparin, age, gender, ASA, NSAIDs,
traumatic placement, spinal stenosis
Leg weakness, numbness and bladder/bowel
disturbance are first signs
 If not evacuated within 8-12 hours, usually leads to
permanent paralysis
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Complications
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Epidural Hematoma
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Risks
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Abnormal coagulation
Elderly
 Female
 Debilitated patients
 Traumatic insertion
 Unknown spinal pathology
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Complications
Anticoagulation and Epidurals:
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ASA – OK
NSAIDS – OK
UFH 5000 sc bid – OK if no other antiplatelets
UFH 5000 sc tid – sort of OK, but not really (according to
ASRA)
LMWH (Dalteparin)– increased risk – not really OK
IV heparin – not OK
Clopidigrel, ticlodipine – not OK
Coumadin – not OK
Ideal Patient Care
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Surgeons, APMS, nursing all working for same
goal
Pre-operative optimization
Intra-operative care
Post-operative
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Ambulation, pain, bowels, voiding
Improved patient recovery
Acute Pain Management Service
(APMS)
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Consulting service, mostly post-op patients
PCAs, non-labour epidurals, regional techiques
Don’t need to co-sign our orders
Can’t order any analgesics, anti-emetics,
antihistamines, neuropathic pain agents, or
sedatives while patient being followed by APMS
“Suggest Orders” once APMS signs off DO
need to be co-signed