Assessment of acute pain:
Consider a Functional Activity Score such as Scott and McDonald 2008
3.2.1 - Discuss the role of an acute pain service.
Benefits of APS
Reduced pain
Less side effect
Reduced postoperative mortality and morbidity
Reduced incidence of persistent postoperative pain
Cost-effective
APS role:
Education health professionals and organisations (collaborative)
Advanced analgesic techniques
Improve analgesic regimes
Standardise use of the equipment and ‘standard’ orders
24-hour available pain personnel
Quality improvement
Research role (collaborative)
Policies and procedures should include:
Education and training of health care providers
Monitoring of patient outcomes
Documentation of monitoring activities
Monitoring of outcomes at the institutional level
24-hour availability via anaesthetics
A dedicated APS
3.2.2 - Discuss general requirements that might enable safe and effective delivery of
all acute pain management techniques in hospitals including: education of
staff and patient monitoring requirements; responses to inadequate or
excessive medication; use of “standard orders”; and equipment used.
APS Standard orders should include
Drugs to use
Education of nursing, medical staff and patients
Monitoring requirements including analgesic and OIVI
Response to inappropriate analgesia
Response and treatment of side effects
Nursing procedures and protocols
Equipment used
3.2.3 - Discuss the issues related to the ongoing management of acute pain
following discharge from the hospital.
Determine the appropriateness of further opioid prescription at discharge
Opioids should be prescribed according to the duration of treatment required rather than the maximum available
Avoid prescribing more than 5-7 days
All patients should see their primary care provider within 5-7 days
Avoid prescribing slow-release medications unless on these long term and there are rare extenuating circumstances
Record all plans and information in the electronic medical record
Discuss issues with driving with altered opioid dose
Important communication to the primary care provider in a timely manner
Discuss with the patient education about how to use medication
How to store medication
How to dispose of unwanted medication
3.2.4 - Evaluate the role of acute pain management in rehabilitation, including
enhanced recovery or “fast-track” surgery.
Key steps in an ERAS program
- Presurgery
1. Education
2. Counselling
3. Carbohydrate drinks
4. Epidurals for pain
- During surgery
1. Fluid management
2. Judicious opioids
3. Reduce surgical trauma/incision
4. Minimise transfusion
- Post-surgery
1. Early mobilisation
2. Early removal of drains and tubes
3. Early transition to oral pain meds
4. Early allowance of food
Benefits of ERAS
1. Increased patient satisfaction
2. Less postoperative complications
3. Decreased length of hospital stay
4. Improved use of hospital resources
5. Reduced readmissions
Principles of pain management in ERAS
1. Use multimodal analgesia
2. Use regional analgesia
3. Avoid opioids as possible
4. Transition to orals early
3.2.5 - Discuss the risk factors and mechanisms involved in the transition of acute to
chronic pain, and critically evaluate the evidence for measures that may
mitigate this transition.
Acute to Chronic pain:
Central and peripheral sensitisation processes
The degree of inflammation and tissue damage may potentiate these effects
Preventing Acute to Chronic pain
Avoid surgery where possible
Regional anaesthesia and epidurals
Possibly IV lignocaine or IV ketamine (3 small trials only with possible positive effect)
Pharmacology for prevention remains unclear (Cochrane level evidence)
The multimodal approach may reduce the incidence and severity of chronic post-surgical pain
Type of surgery performed (minimally invasive)
Multidisciplinary approach
Maybe patient education though evidence to date has been disappointing
3.2.6 - Describe the pharmacokinetics and pharmacodynamics of opioids and local
anaesthetics administered into the epidural space or cerebrospinal fluid.
Epidural Pharmacokinetics
The rate of diffusion into CSF is slower (Volume, concentration, lipophilicity, protein binding, CSF flow rate
Epidural spaces are irregular, segmental, and encircles the dural sack
Two-compartment model - Rapid into epidural fat - then back out
Normal metabolism and elimination as peroral intake.
Intrathecal Pharmacokinetics
High CSF concentration and short diffusion distance
Baracity affects flow of medication
Slow absorption with increased half-life - the more lipophilic the faster cleared
Normal metabolism and elimination otherwise
3.2.7 - Describe the physiological consequences of a central neuraxial (epidural or
intrathecal) block with local anaesthetics and/or opioids.
Local anaesthetics
Local anaesthetic injected into the epidural space diffuses through the dura and subarachnoid membranes in a band like distribution to the nerve roots
This results in blockade of motor, sensory and autonomic fibres of the associated level
Opioids
Analgesic effect of opioids binding to opioid receptors in the dorsal horn of the spinal cord after crossing the dura and arachnoid membranes
Some absorbed into epidural blood vessels
Rostral spread carrying opioid towards the brainstem
The less lipid-soluble, the more rostral drift
Physiological consequences at particular levels
Respiratory
Thoracic
Blockade of intercostals and abdominal wall muscles
Loss of vital capacity
Loss of accessory muscle use
Cervical
Diaphragmatic blockade C3-5
Brainstem
Respiratory centre depression
Cardiovascular
Sacral - minimal parasympathetic pelvic organ block only
Lower thoracic/lumbar - Arteriolar and venous vasodilation in lower abdomen and limbs
Upper thoracic - Loss of cardio accelerator fibres above T5 - reduced HR and contractility
CNerves - Vagal blockade will reduce PNS tone and attenuate some loss of SNS
Brainstem - Inhibition of vasomotor centre and profound drop in CVS parameters
3.2.8 - Describe the adjuvant agents that may be used to enhance the quality or
extend the duration of central neuraxial or other regional analgesia blocks,
and discuss their mechanisms of action, risks and benefits.
Clonidine
Descending inhibitory system effects
Thought to be safe with LA
Reduces LA dose
Improved duration and extends motor blockade
SE: Sedation, hypotension, bradycardia
Adrenaline
Vasoconstriction slows the clearance of epidural drugs
The benefit with both LA and opioid
Dexamethasone
Dexmedetomidine (alpha 2 agonist) - Binding
3.2.9 - Discuss the contribution of maladaptive psychological coping skills and
psychiatric illness and socio-environmental factors to the experience of acute
pain (pain ratings, opioid use) and the risks of persistent pain and prolonged
opioid use after discharge from hospital.
Anxiety level is strongly associated with the intensity of the surgical pain experience
The higher the anxiety score, the higher the postoperative pain intensity
Preoperative depression has predicted postoperative higher pain scores following prostate surgery
3.2.10 - Discuss assessment of acute pain (including acute neuropathic pain) in the
adult patient, including the nonverbal patient and those from indigenous or
other culturally and linguistically diverse communities, and the relevance of
functional assessment.
See guide on Indigenous populations (LINK)
Numeric scores can be used (VRS, VAS, Faces scales)
Functional activity scores are thought to be better however less evidence/studies
FAS = A no limitation, B mild limitation, C severe limitation
PainAD & FLACC
Abbey pain scale
3.2.11 - Discuss assessment of acute pain in the older patient (especially those with
dementia) including difficulties, relevance of functional assessment and use
of other pain evaluation methods that do not rely on verbal ability
Algoplus can be used
PainAD can also be used
3.2.12 - Discuss assessment of acute pain in children including difficulties, relevance
of functional assessment and use of paediatric pain scales.
3.2.13 - Recognise causes of delirium in the acute pain setting and the effect this may
have on assessment and treatment of the patient with acute pain.
No tools have been studied in this population - all regular management steps for delirium apply
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