Transcript Intrathecal Narcotics for Post

Intrathecal Narcotics for Postoperative Analgesia
Kristopher R Davignon, MD
Dept of Anessthesia Grand Rounds
March 2007
Intrathecal Narcotics
• Opioids were know to the ancient
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Sumerians as of 4000 B.C.
1971 Opioid receptor discovered
1973 Receptors found in the brain
1976 Receptors found in the spinal cord
1979 Early reports of intrathecal opioids
producing analgesia
Intrathecal Narcotics
• Thoracic and Upper Abdominal Procedures
• Elective Total Hip Arthroplasty
• 350,000 Procedures per year in the US
• + 5 min to consent
• + 15 min for procedure
Overview and Goals
• Anatomy, Physiology & Pharmacology
• Complications
• Evidence Based Practice
• Dose-Response
• Future Directions
Anatomy, Physiology &
Pharmacology
Anatomy, Physiology &
Pharmacology
• Drug disposition depends primarily on lipid
solubility
• Any drug rapidly redistributes
• opioid is detectable in the cisterna magna
within 30 min of lumbar intrathecal
administration
Anatomy, Physiology &
Pharmacology
• Opiods
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• Non Opiods
Morphine
Meperidine
Hydromorphone
Sufentanil & Fentanyl
Methadone
Preservative
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Clonidine
Neostigmine
Adenosine
Epinephrine
Ketorolac
Midazolam
Anatomy, Physiology &
Pharmacology
• Lipophilic opioids
• Rapidly traverse the dura; sequestered in
epidural fat (and enter systemic circulation)
• Rapidly penetrate the spinal cord and bind
receptors and nonspecific sites
Anatomy, Physiology &
Pharmacology
• Hydrophilic opiods
• Limited binding to epidural fat and nonspecific
receptors
• Slower transfer to systemic circulation
• Higher CSF concentrations accounting for
rostral spread
Anatomy, Physiology &
Pharmacology
“Complications”
• Pruritus
• Mechanism unclear – likely opiod
receptor mediated (not histamine)
• Incidence 30-100%
• Rx: Antihistamines, 5-HT3
antagonist, opiod antagonists (or
agonist-antagonists), propofol
“Complications”
• Urinary Retention
• Not dose dependent
• Can last 14-16 hours
• Most frequent with Morphine
• 35 % incidence
• Mechanism related to sacral parasympathetic
outflow inhibition
• Allows increase in maximal bladder capacity
“Complications”
• Nausea and Vomiting
• Incidence 30 %
• Most profound with Morphine
• Likely due to cephalad migration of drug to
area postrema
“Complications”
• Respiratory Depression
• Incidence is dose dependent
• Very Rare 0.09% to 0.4%
• Likely no more clinically relevant than for IV
narcotics
• Monitoring for 18-24 hours when using
lipophilic opiods
“Complications”
• PDPH
• Age, Gender, History of PDPH, Obesity
• Multiple dural puncture, Needle size, Needle
design
“Complications”
• PDPH
• Rx:
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hydration
Caffeine
Sumatriptan
ACTH
EBP
“Complications”
• Neuropraxia/Paralysis
• Epidural hematoma
• Epidural abcess
Evidence Based Practice
• What types of surgery is amenable to
intrathecal narcotics?
• What doses should we use?
• What outcomes can we affect?
Types of Surgery
• Thoracic
• Including Cardiac
• Intra-abdominal
• Including C/S, AAA, Open Cholecystectomy
• Lower Extremity
• Including THA & TKA
• Narcotic Only (worst)
• Narcotic + LA (best)
• LA Only
“the Dose”
• 1) Optimal dose depends on the surgical
procedure
• 2) Incidence of side effects increases in
proportion to dose (especially with doses >
300 ųg)
“the Dose”
Dosing for THA
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Use lowest dose possible!
Studies have used doses as low as 0.025 mg
Older studies used doses as high as 0.5mg
Ideal dose seems to be 0.1 mg
• Lower doses don’t provide good analgesia
• Higher doses plagued with pruritis
Dosing for THA
Dosing for THA
Affecting Outcomes
Do Improved Pain Scores
Matter?
Future Directions
• Anticoagulants
• Use of stents and anti-platelet agents
• Aggressive DVT prophlaxis
• Absence of laboratory evidence of these agents
• Sustained release neuraxial narcotic
• Depodur
Future Directions
•Depodur (morphine sulfate extended release liposome injection)
DepoFoam™ Encapsulation
DepoFoam™ Particle (diameter: 15 microns)
Reference: SkyePharma Website. DepoFoam ™ overview.
Please see full Prescribing Information.
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Drug-filled Chamber
Future Directions
DepoFoam™: Appearance of Formulation
Settled Particles
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Vials of DepoDur™ should be gently inverted to resuspend
the particles immediately prior to withdrawal from the vial.
Aggressive agitation should be avoided.
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Vials shown are for demonstration purposes only. Actual DepoDur ™
vials are amber in color and the liquid inside is not easily visible.
Please see full Prescribing Information.
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Resuspended Particles
Future Directions
• Better Pain Scores for 48 hours
• Studied in Hip Arthroplasty, Cesarean Section, Lower Abdominal
Surgery
• No significant difference in side effects from IV narcotic
Conclusions
• Pain management in the in-patient setting is
becoming a priority for adminstrative
organizations
• A majority of in-patient pain management is
post-operative
• Neuraxial narcotics consistently reduce
patient’s VAS