Multimodal Flashcards
The emphasis on Multimodal anesthesia for general anesthesia includes these two aspects:
Short acting anesthetic agents and opioid sparing
Nonopioid alternatives for the treatment of pain
PT/OT, Massage, acupuncture, behavioral, topical medications, cold/heat, exercise, weight loss, diet/nutrition, yoga/taichi, TENS, OTC meds, interventional pain management, nonopioid anesthesia
Acetaminophen doses (preop, intraop, postop)
- preop: 1000mg PO
- intraop: Ofirmev 1g IV
- postop: 1000mg PO tid
Which multimodal drugs can be given preop to reduce pain
- acetaminophen 1000mg PO
- gabapentin 300mg PO
- celebrex 100-200mg PO
Which multimodal drugs can be given intraop to reduce pain
- Ofirmev 1g IV
- Maintain GA with VA
- Ketamine
- Magnesium 30-60mg/kg (max 6g) over 1 hr
- lidocaine 1mg/kg over 1 hr
- Ondansetron
- Decadron
- Ketorolac
- Ibuprofen 200-800mg IV over 30min
Which multimodal drugs can be used for pain post-op
- Acetaminophen 1g tid
- Mag supplement 400-600mg bid
- gabapentin 300mg tid
- Celebrex or advil TID (as permitted by surgeon)
MOA for gabapentin
structural analogue of GABA, binds to vg-CA++ channels
- enhances descending inhibition
- inhibits excitatory neurotrasmitter release
Is gabapentin protein bound?
no, <3%
Is gabapentin lipid or water soluble
lipid
What are uses of gabapentin
- partial seizures
- chronic pain syndromes: diabetic neuropathy, post-herpetic neuralgia, reflex sympathetic dystrophy, phantom limb pain, fibromyalgia
For gabapentin to treat pain, it must be given ________
prior to surgery, 1-2hrs, only works for preemptive analgesia
When is gabapentin contraindicated
MG and myoclonus
what are s/e of gabapentin?
- somnolence
- ataxia
- fatigue
- vertigo
- GI disturbance, constipation
- seizure if abrupt withdrawal
- weight gain
MOA of NSAIDs
COX1/2 inhibition, inhibits synthesis of prostaglandins
Which COX is constitutive
COX-1
Which COX is inducible
COX-2
What is COX-2 responsible for
pain, inflammation, fever
What is COX-1 responsible for
gastric protection, hemostasis, renal function
3 uses of NSAIDs includes
- analgesic
- anti-inflammatory
- anti-pyretic
Which NSAIDs are non-specific
- ibuprofen
- naproxen
- ASA
- acetaminophen (?)
- ketorolac
Which NSAIDs are COX-2 selective
- Celecoxib (Celebrex)
- rofecoxib (Vioxx) : banned in US
- valdecoxib (Bextra) : banned in US
- parecoxib (Dynastat): banned in US
COX-2 selective NSAIDs compared to nonspecific
- comparable analgesia
- lack of effect on platelets
- less GI effects
- increased MI and CVA risk
- dosage-ceiling
Celebrex dosage
200-400mg PO qday
celebrex peak time
3hrs
MAO of acetaminophen
reduces prostaglandin metabolites
max dose of acetaminophen per day
4g
peak time of acetaminophen
PO= 1-3hrs
IV= 30min- 1hr
duration of action of acetaminophen
6-8hrs
ketorolac (Toradol) MOA
inhibits PG synthesis by inhibiting COX1 and 2
C/I of ketorolac (Toradol)
- severe renal impairment
- significant risk for bleeding
- CAD/CABG
- pregnancy
- NSAID allergy
- decrease dose in elderly
ketorolac (Toradol) peak timing
45-60min IV, give during emergence
keotolac (Toradol) dose
15-30mg IV q6hr; max 60-120mg qDay
half dose in elderly
Lidocaine dose
1-2mg/kg IV (initial bolus) over 2-4min
1-2mg/kg/hr drip
terminate 12-72hrs
what should be carefully monitored when using lidocaine for analgesia
cardiac, hepatic and renal function
Plasma lidocaine concentrations and effects
- 1-5mcg/ml = analgesia
- 5-10mcg/ml = circumoral numbness, tinnitus, skeletal muscle twitching, systemic hypotension, myocardial depression
- 10-15 mcg/ml= seizure, unconsciousness
- 15-25 mcg/ml= apnea, coma
- > 25mcg/ml = cardiovascular depression
Magnesium MOA in analgesia
- anti-nociceptive effects
- N-methyl-D-aspartate (NMDA) receptor antagonist
probably potentiates opioids centrally and peripherally
Magnesium helps regulate
- Ca++ access into cell and actions within cell
- neurotransmission
- cell signaling
- enzyme function
Magnesium has ____ passage across BBB
limited
Magnesium use for analgesia is C/I in
MG and renal failure
Magnesium doses for analgesia
preop: 50mg/kg IV
intraop: 8mg/kg/hr IV
magnesium use as analgesic can cause
bradycardia and hypotension
side effects of ondansetron (zofran)
QT prolongation (give slowly to prevent)
HA, constipation
ondansetron (zofran) E1/2time
4hrs
Ondansetron (zofran) dose
adult: 4-8mg IV
ped: 0.1mg/kg IV
Corticosteroid MOA in analgesia
MOA unknown:
- glucocorticoid receptors in nucleus tractus solitarius (a cluster of neurons located in the brainstem, specifically in the dorsal medulla oblongata. It plays a crucial role in processing and integrating sensory information from various organs)
- increase effectiveness of 5HT3 antagonists and droperidol
-anti-inflammatory; inhibition of phospholipase and cytokines and stabilization of cellular membrane
dexamethasone (Decadron) dosing
8-10mg IV
dexamethasone (Decadron) onset
delayed; 2 hrs, efficacy persists for 24hrs
What is adverse effects of dexamethasone (Decadron)
perineal burning/itching if given rapidly
dexamethasone (Decadron) is useful as an adjunct with ________ because it increases duration
nerve blocks, both when given IV or in the block
Dexmedetomidine (Precedex) MOA
highly selective, specific (pontine locus coeruleus), potent, and full a2 adrenergic agonist.
clonidine is a ______ a2 agonist
partial
precedex is ______ selective than clonidine
7-10x more selective
What is the antagonist to dexmedetomidine (Precedex)
Atipamezole
dexmedetomidine (precedex) uses
- conscious sedation: calmness, easily rousable, preserves spontaneous ventilation (high dose can collapse upper airway), amnesia not assured
- GETA: tracheal intubation, decreased perioperative opioid requirements
- TIVA: depression of ventilation, use LMA or ETT
dexmedetomidine (precedex) E1/2time
2-3hrs
CV side effects of dexmedetomidine (Precedex) include
hypotension, bradycardia
dexmedetomidine (precedex) dosage
- TIVA/GETA: 0.5-1 mcg/kg bolus, 0.1-1.5mcg/kg/hr infusion.
- sedation: 0.2-0.7mcg/kg/hr IV
- IV regional: 0.5mcg/kg with lidocaine
- Neuraxial:
spinal= 3mcg, 5mcg with fent 25mcg
epidural= 2mcg/kg
