Mostly Prop, some K, NSAIDS Flashcards
What class is prop and why is it different from other IV sedatives?
: Sedative/hypnotic
because it is a hypnotic
Induction dose prop
1.5 – 2.5 mg/kg IV
how long does it take to become unconscious from prop?
about 30 seconds
[moves from stage 1 to stage 3 fast]
Major advantage of prop
Rapid awakening with minimal residual CNS effects
[patients can go home fast]
Chemistry of prop
1% solution in soybean oil, glycerol and egg lecithin (a long-chain triglyceride)
why is the chemistry important of prop?
Supports bacterial growth
Can increase plasma triglyceride levels
preservatives of diprivan
disodium edetate & NaOH
preservative of generic prop?
metabisulfite
Propofol known for pain at injection site, so it is common to mix with lidocaine. What is risk of this?
Propofol + lidocaine – coalesced oil – risk of pulmonary emboli
causes genital burning
aquavan due to formaldehyde
Brand of prop that causes increase injection site pain
ampofol
MOA of prop
GABAA receptor agonist (inhibitory neurotransmitter)
GABAA stimulation = hyperpolarization of cell membranes which causes receptor to not work
Uptake of prop
lungs and liver (cytochrome P-450)
Elimination ½ time prop
0.5 – 1.5 hrs
Context sensitive ½ time of prop
<3 hrs = 10 min
>3 hrs = 25 min
>8 hrs = 40 min
metabolism of prop?
Glucuronidation (liver) is major metabolic pathway
Excretion of prop?
excretion mostly through kidneys however Liver and/or renal disease does not impair elimination.
can you give prop to laboring moms?
YES! Crosses placenta but rapidly cleared from neonatal circulation so baby will be breathing, just make sure mom is stable
difference in peds dose of prop?
Require ↑ dosing d/t ↑ Vd and faster clearance (you can give like 4-5X dose)
difference in elderly dose of prop?
↓ dosing d/t ↓ Vd and slower clearance
sedation dose of prop?
25 – 100 mcg/kg/min
Agent of choice for short, endoscopic cases
prop
Maintenance dose prop?
100 – 300 mcg/kg/min (↓ with opioids and volatiles)
cool effect of prop that we like to use?
antiemetic! almost equal to zofran
how much prop to use as an antiemetic?
Small dose (10-15 mg) in PACU & with chemo induced N/V
Why is prop an antiemetic???
Possibly a direct depressant effect on vomiting center
5 non-anesthetic effects of prop
- antiemetic 10-15 mg
- antipruritic 10 mg
- anticonvulsant 1mg/kg
- bronchoconstriction
- Analgesia
dose of 1 mg/kg or greater of prop is useful as
↓ seizure duration during ECTs
anticonvulsant
what causes the bronchoconstriction seen with prop?
Metabisulfite (generic propofol) can cause bronchoconstriction (asthma, smokers)
what type of pain is prop decent for?
Not good for nociceptive pain (somatic, visceral); some analgesia for neuropathic pain (abnormal CNS processing of painful stimuli)
Neurologic effects prop
↓ CMRO2, ↓ cerebral blood flow, ↓ ICP
Cardiovascular effects prop?
↓ HR, ↓ SVR, ↓ cardiac output Commonly offset by laryngoscopy, intubation or LMA insertion
causes Extreme ↓ BP with prop admin
hypovolemia, LV dysfunction, elderly
why is prop good for ablations?
no SA or AV node effects or QTc prolongation
Profound bradycardia and/or asystole
Propofol Related Bradycardia
Increased incidence of Propofol Related Bradycardia
surgeries dealing with muscles of eyeball and oculocardiac reflex
treatment of prop brady?
glycopyrolate, epi
who is more prone to prop related brady?
younger more prone, remember they are HR dependant
oculocardiac reflex is
stimulation of cranial nerve V and X - vagal nerve
Dose-dependent Respiratory depression with prop causes
apnea, decrease RR and TV
what is prop enhanced and offset by?
Enhanced by opioids
Offset by surgical stimulation
what type of shift of hypoxic response curve will you see with prop?
downward (neg effect)
what is a positive effect of prop that we do not want to interfere with?
Hypoxic pulmonary vasoconstriction (HPV)
what causes benign green urine with no renal dysfunction with prop?
Phenol
Prolonged infusion of prop can lead to
liver injury and propofol infusion syndrome
benign cloudy urine with prop is caused by
uric acid
why is prop Good for lap trendelenburg procedures
↓ IOP after induction, sustained through intubation
what does prop do to coags??
No change in coag factor or platelet function
Inhibits platelet aggregation
4 lipid related effects prop?
Risk of infection
injection site pain
hypertriglyceridemia
pulmonary embolus
Allergic Reaction of prop related to
Phenol related anaphylaxis (often after 1st exposure with neuromuscular blockers)
Is Propofol Safe for Patients with Egg Allergies
We found no evidence of a relationship between foodallergyhistory and perioperativepropofolreaction.”
Seen after >75 mcg/kg/min for >24 hours (ICUs)
Propofol Infusion Syndrome
how to spot prop infusion syndrome?
Tachycardia during propofol anesthesia is sign of lactic acidosis, then profound bradycardia
Mechanism of prop infusion syndrome?
Mimics mitochondrial myopathy (abnormal lipid metabolism in smooth and cardiac muscle)
Hyperchloremic metabolic acidosis (NS) and ↑ organic acids (DM ketoacidosis, tourniquet release)
differential diagnoses of prop infusion syndrome
tell me About Seizure Activity with prop?
Can cause seizure-like myoclonus after injection
Not cortical epileptic in origin
During EEG, does NOT induce seizures in epileptic patients
No contraindications with epileptic patients
Accounts for 40% of KNOWN substance abuse in anesthesia practitioners
prop, it is a problem
PCP derivative – dissociative anesthesia (thalamocortical and limbic systems)
Ketamine
what will you see when you give K to patients?
Amnesia, analgesia, eyes open, spontaneous ventilation
Major disadvantage of K
Emergence delirium (ED)
what isomer is most commonly used of K and why
Racemic (R) most commonly used d/t more intense analgesia with fewer side effects.
MOA of K?
Non-competitive binding to N-methyl-D-aspartate (NMDA) receptors (antagonist) Inhibits glutamate (excitatory transmitter) binding to glycine (required for NMDA receptor activation) Inhibits catecholamine uptake into post-ganglion nerves (like cocaine)
5 other receptors K effects?
Opioid, monoaminergic, muscarinic, Na+ and Ca++ channels, nicotinic acetylcholines
K Interacts with all opioid receptors and is
Synergistic with
opioid, dopamine and serotonin agonists to promote dissociation
Anti-muscarinic properties of K include
bronchodilation, sympathomimetic, anti-erectile dysfunction
Anti-nicotinic properties
may play role in analgesia
onset and duration k
rapid 30 seconds onset and short duration of 5-15 mins dd
what causes psych effects after emergence from ketamine
Redistributes from ↑ to ↓ perfusion tissue r/t high lipid solubility
elimination ½ time K
2 – 3 hours
Metabolism K and excretion
Hepatic (cyto P-450) and kidneys
byproduct of K that we like?
norketamine bc it contributes to prolonged anesthesia
what will you see with repeated doses of K?
Repeated doses - enzyme induction - analgesic tolerance - dependence
Clinical uses of K?
analgesia chronic pain syndrome OB bc no neonatal depression psych induction
what meds are good for chronic pain syndromes
Ketamine. Mg++ and dextromethorphan
Ketamine useful specifically for these types of pts with psych?
PTSD, also good for depression
induction dose K
1-2 mg/kg IV; 4-8 mg/kg IM
onset K
LOC in 30-60 sec IV, 2-5 mins IM
how long does it take to Return to consciousness
approx. 15 minutes; full orientation in 60-90 minutes
Major indication of k
burns
caution k admin with these patients
CAD, pulm hypertension, high icp, critically ill
↑ dose of k causes
burst suppression; anticonvulsant (does not alter seizure threshold)
how does k effect Hemodynamics
↑ everything (BP, HR, CO, myocardial work and O2 demand)
Can be offset with benzos and volatiles
ventilation reflixes mainly stay in tact, but important to consider what
aspiration risks should be intubated and give an antisialagogue
Psychedelic Effects K
Visual (including transient blindness), auditory, vivid (full color) dreams, “floating”, hallucinations, delirium: some up to 24 hrs
↑ risk factors for psych effects
> 15 years, female, >2 mg/kg/IV, personality disorders
how do you prevent emergence delirium with k
Benzodiazepines most effective (midazolam better than diazepam)
Common “cocktail”: IV midazolam and glycopyrrolate before or with ketamine
NSAIDS are
Analgesic, Anti-inflammatory, Antipyretic
COX-1 Non-selective inhibitors advantage
↓ platelet aggregation
COX-1 Non-selective inhibitors disadvantage
↓ renal function,
↑GI toxicity,
↓ platelet aggregation*
cox 2 selective advantages
↓ pain, inflammation, fever
↓ GI toxicity
no platelet effects
cox 2 selective disadvantages
↑ CV risk
where do the unwanted side effects from nsaids come from
cox 1 receptor
what does it mean when nsaids are highly protein bound?
means drug cant reach receptor because it is bound to the protein so you will see greater effects in ppl with low protein syndromes
metabolism and excretion of nsaids
Liver metabolism, renal excretion
↑ GI risks with nsaids seen with
High dose, older age, H. pylori or ulcer history; combined with ASA, anticoagulants, corticosteroids
CV risks when taking nsaids
MI, heart failure, HTN
Naproxen appears to have ↓ risk with what major side effect nsaids
cv
what can nsaids do to the kidneys and liver
NSAIDs can ↓ GFR
↑ LFTs and liver failure
patients with cards issues should be on what nsaid
naproxen according to aha
What patients have an increase of anaphylaxis with nsaids?
Pts with allergic rhinitis, nasal polyps, asthma r/t prostaglandins
Potent analgesic, moderate anti-inflammatory, anti-pyretic
Ketorolac (Toradol)
30 mg IM/IV of toradol is equal to
analgesia of MSO4 10 mg or meperidine 100 mg without CV or respiratory depression, minimal N/V but watch out with kidney patients
onset and peak effect
onset dd 30-1 hr
peak 2-3 hrs [give faster acting until this kicks in]
A OK protocol
atropine 1 mg for vagolysis
ondansetron 8 mg to block serotonin/vagolysis
ketorolac 30 mg block thromboxane
Analgesic, antipyretic, insignificant anti-inflammatory action
Acetaminophen
Leading cause of acute liver failure in U.S?
Acetaminophen r/t Metabolite: NAPQI (depletes antioxidant glutathione, directly damages liver cells)
To ↓ liver toxicity risk, FDA recommends
≤ 2600 mg/day, ≤ 650 mg single dose.
dose of iv acetamet
> 13 yo: 1 gm/15 minutes;
2-13 yo: 15 mg/kg
Oldest, most widely used medicine in the world.
“Separated” from other NSAIDs because of its cardiovascular and cerebrovascular benefits.
Aspirin (ASA)
what causes prolonged platelet aggregate inhibition with asa
Irreversibly inactivates COX-1
Toxicity (all NSAIDs): 8
N/V, abd pain, tinnitus, CNS depression, metabolic acidosis, renal failure, agitation, coma, hyperventilation (compensation)
treatment for nsaid tox even though there is no antidote
Treat symptoms, hydrate, alkalinize urine, consider charcoal, hemodialysis
Key point of eras
Multimodal analgesia = concurrent use of non-opioid analgesics and opioid sparing techniques to minimize opioid related adverse effects.
Pre-op eras?
Combo of acetaminophen, NSAID and gabapentanoid
intraop eras
Regional anesthesia or non-opioid analgesic technique
post op eras
Continuation of 1) regional analgesia, especially if NPO; 2) acetaminophen; 3) NSAID; 4) gabapentanoid on scheduled (not PRN) basis
