18.6 Chronic Opioid Use + Spinal Adjuncts Flashcards
a) How should you manage the perioperative opioid requirements of a patient who is having elective
surgery and who takes regular opioids for non-malignant pain? (8 marks)
Meet preoperatively
ideally with team interested in pain
Establish current use / indication / methods delivery
total daily dose
Establish control - well controlled / poor
acute pain now that needs treating?
Calculate total dose - if on methadone or long acting opioid continue regular
if not tolerating oral siwtch to patch / s/c other method
Multimodal analgesic approach
ensure simple anaglesics commenced - paracetamo
nsaid if tolerate
Does current condition require additional breakthrough
Regional
Perform procedures under RA where possible or use for analgesia
eg arm procedures under upper limb block
intraabominal consider epidural or blocks -tap
adjunct ketamine / gabapentinoids
regularly assess pain
higher level bed if needed post op
pain team
_________________________
Preoperative:
» Ensure the patient’s preoperative
pain is fully managed.
Delay non-urgent surgery if not yet fully optimised.
Involve chronic pain team.
May include use of non-opioids.
> > Establish the reason for the patient’*
opioid analgesia use.
This may have
implications for the perioperative period,
e.g. positioning limitations.
> > Establish drug, dose, duration of use,
route of administration.
> > Formulate plan for postoperative
pain relief depending on the nature of
surgery,
e.g. degree of pain likely to be involved,
whether patient will be
able to take medications via oral route,
make calculations of equivalence
if patient’s condition will dictate conversion to intravenous analgesia
postoperatively.
Need to ensure usual 24-hour dose
PLUS extra to
manage the pain from surgery.
> > Normal doses of oral slow release
and immediate release opioids to be
taken on day of surgery.
Patch - see other slide
Intraop:
> > Awareness that larger doses of
morphine intraoperatively will be
required to achieve the same effect
compared with opioid-naïve patients.
> > Use of regional techniques,
where feasible, to reduce overall opioid
requirement.
Postoperative:
» Regular input from inpatient acute pain team.
> > Higher bolus doses of morphine in
PCA will need to be kept under review
regularly as equivalence calculations are approximate: the patient is therefore at risk of both unrelieved pain and narcosis.
> > Use pain scores to assess for unrelieved pain.
> > Be aware of signs of withdrawal
(adrenergic hyperactivity, generalized malaise, abdominal cramps, yawning, and perspiration).
> > Be aware of signs of overdosing (sedation, low oxygen saturations, reduced respiratory rate, small pupillary size).
> > In view of the risk of either overdosing or withdrawal, it may be appropriate to manage the patient in a higher dependency setting than would normally be dictated by the nature of surgery, or extended recovery may be required.
> > If intravenous morphine is used,
convert back to oral dosing as soon as
is feasible (consider any change in renal function postoperatively and its
impact on opioid clearance).
b) Give the conversion factors for oral tramadol, codeine and oxycodone to the equianalgesic oral
morphine dose. (3 marks)
Tramadol 0.15 67 mg
Codeine 0.1 100 mg
Oxycodone 2 5 mg
c) What are the perioperative implications
of an existing spinal cord stimulator? (6 marks)
> > Preoperatively, make contact with
the team who manages the patient
to check battery life and any other issues.
> > Bipolar diathermy should be used wherever possible. If unipolar absolutely necessary,
position the return plate to
avoid electrical passage
through the SCS.
> > Neuraxial block likely to be contraindicated
(risk of infection or direct lead
damage).
If considered essential,
consult the pain team who manages
the patient’s SCS and perform under fluroscopic/ultrasound guidance to
avoid the device.
d) What additional perioperative precautions should be taken if the patient has an intrathecal drug
delivery system fitted? (3 marks
> > Spinal anaesthesia by lumbar puncture
should be avoided, although
intrathecal bolus may be given via the device if it is at a suitable level.
However, the system will be primed with
the usual drug it delivers,
beware delivering a large bolus along with the intended bolus.
> > Meticulous aseptic technique when
utilising the ITDD to avoid risk of
infection.
> > Epidural anaesthesia is feasible
above or below the ITDD site.
> > Opioid dosing as for opioid naïve patient
(unless patient also takes oral opioids).
No diathermy within 30 cm of pump or catheter.
Opioid patches
Intraoperative:
» The decision as to whether to
continue opioid patches depends
on the nature of surgery.
For example, it may be appropriate
to continue patch with non-opioid analgesics
and immediate-release oral morphine for
breakthrough if day case surgery with low predicted pain (e.g. minor orthopaedics),
whereas if the patient is to have major surgery and need for intravenous morphine is predicted,
it would be more appropriate
to calculate the equivalent dose of
intravenous morphine and include
this in the overall predicted 24-hour morphine dose.
Furthermore, transdermal absorption
perioperatively may not be reliable and is certainly
not titratable.
Buprenorphine is a partial antagonist so may complicate top-up dosing with morphine.
All staff should be made aware of the
physical location of the patch (if it is left on)
so that it may be removed in
the case of narcosis.
Spinal cord stimulator is
Spinal cord stimulators (SCSs) are used for
neuropathic pain, CRPS,
and ischaemic pain due to
angina or peripheral vascular disease.
They achieve their effect through
gate control theory
and
also modulation of release of other neurotransmitters.
Leads are surgically placed in the dorsal epidural
space (usually requires laminotomy)
or percutaneously via Tuohy.
During trial period, the pulse generator is left external to the body to check efficacy.
The pulse generator can then be placed in a subcutaneous pocket (e.g. abdomen, gluteal) and the leads tunnelled subcutaneously to it.
Intrathecal drug delivery systems (ITDD
Intrathecal drug delivery systems (ITDDs)
deliver drugs to the dorsal horn:
opioids, local anaesthetic, clonidine or ziconotide for refractory pain or baclofen for spasticity.
The pump may be external or fully implanted with
reservoir filling performed percutaneously.
It may have a fixed rate or be programmable.
It may be sited anywhere from thoracic level to the second sacral segment.
Risks: dural granuloma formation, leg oedema, infection.
