IV Anesthetics Flashcards
What is the chemical name and class of Propofol?
2,6 - Diisopropylphenol
isopropylphenol
What is the mechanism of action of propofol?
Direct GABA-A agonist -> ↑ Cl conductance -> neuronal hyperpolarization
What is the induction and infusion dose of Propofol?
Are they based on LBW or TBW?
induction: LBW, 1.5-2.5 mg/kg
Maintenance: TBW, 25-200mcg/kg/min
What is the onset and duration of propofol?
onset: 30-60 sec
duration: 5-10 minutes
How is propofol metabolized?
Liver by P450 enzymes and extra hepatic metabolism (lungs)
What does the preservative in Propofol contain?
EDTA
Describe pharmacokinetics of propofol.
Blood concentration declines over time. Rapid distribution to VRG. Redistributes to muscle then fat.
The concentration of propofol in the brain peaks at what time interval?
1 minute
How does propofol affect... BP SVR venous tone myocardial contractility
all decrease
How does propofol shift the CO2 response curve?
down and to the right (less sensitive to CO2)
What effect does propofol have on hypoxic ventilatory drive?
inhibits hypoxic ventilatory drive
How does propofol affect... CMRO2 Cerebral blood flow Intracranial pressure Intraocular pressure
decrease all
What doses of propofol is used as an antipruritic and antiemetic effect?
antipruritic: 10mg
antiemetic: 10-20mg
Can you give propofol to a patient with a egg allergy?
yes, they are likely allergic to the egg white. Propofol comes from the yolk
What can long term propofol infusion cause? What is it?
propofol infusion syndrome. Starves cells of O2, particularly cardiac and skeletal
What are some signs of propofol infusion syndrome?
bradycardia-> asystole, metabolic acidosis, rhabdo, enlarged liver,
What are risk factors for propofol infusion syndrome?
dose > 4 mg/kg/hr (67 mcg/kg/min) Infusion duration > 48 hours Children > adults Inadequate oxygen delivery Sepsis Significant cerebral injury
When should a syringe and infusion of propofol be discarded?
syringe: 6 hours
infusion: 12 hours
Should branded or generic propofol be avoided in asthmatics and infants?
generic. due to preservatives
metabisulfite causes bronchospasm
benzyl alcohol should be avoided in infants
How can propofol injection pain be avoided?
lidocaine before
larger vein
opioid before
Fospropofol is (select 2) a lipid emulsion prodrug pain at injection site metabolized by alkaline phosphate
prodrug
metabolized by alkaline phosphate
What IV induction agent causes genital and anal during on injection?
fospropofol
What is the chemical name and class of fospropofol?
Phosphono-O-methyl-2,6-diisopropylphenol
Isopropylphenol
Is fospropofol a lipid emulsion or aqueous solution?
aqueous solution. doesnt support bacterial growth
What is the mechanism of action of fospropofol?
Is a prodrug, metabolized to propofol by alkaline phosphatase. Slow onset and long duration
What is the induction and repeat dose of Fospropofol?
induction: 6.5mg/kg
repeat bolus: 1.6mg/kg q4min
What is the onset and duration of fospropofol?
onset: 5-13 minutes
Duration: 15-45 minutes
How is fospropofol metabolized?
liver by P450 enzyme and extrahepatic metabolism (lungs)
What is the extraction ratio of propofol and fospropofol? What does this mean?
ER > 0.7
Clearance is dependent on liver BLOOD FLOW.
What is the active metabolite of fospropofol?
propofol!
Formaldehyde is metabolized to formate & excreted in urine
What is the chemical name and class of ketamine?
2-(o-Chlorophenyl)-2 (methylamino) cyclohexanone hydrochloride
Arylcyclohexylamine- Phencyclidine derivative
What kind of mixture is ketamine and its pKA?
racemic mixture
pKA 7.5
What is the MOA of ketamine?
NMDA receptor antagonist
dissociates the thalamus from the limbic system
What are secondary receptor targets of ketamine?
opioid, MAO, serotonin, NE, muscarinic, Na channels
What are the doses of ketamine? Induction: maintenance: low dose infusion: analgesia:
Induction: 1-2mg/kg
maintenance: 1-3mg/kg
low dose infusion: 1-3mg/kg
analgesia: 0.1-0.5 mg/kg
What is the IM and oral dose of Ketamine?
IM: 4-8mg/kg
oral: 10mg/kg
What is the IV and IM onset and duration of Ketamine?
IV: 30-60 seconds, IM: 2-4 minutes
DOA: 10-20 minutes, 60-90 min for full orientation
Where is Ketamine cleared from the body?
liver by P450 enzymes
chronic use causes rapid escalation of tolerance
What is the active metabolite of ketamine? What is its potency?
norketamine, 1/3 - 1/5 the potency
renal excretion
What does ketamine do to... SNS tone Cardiac output HR SVR Pulmonary vascular resistance
increase all
When is ketamine a myocardial depressant?
patient with depleted catecholamine stores or sympathetectomy
Is ketamine a better analgesic for visceral or somatic pain?
somatic
What IV induction agent is a great choice if the patient is actively wheezing?
ketamine, its a bronchodilator
How does ketamine alter the CO2 response curve and respiratory drive?
it doesnt!
What medication is prudent to give your patient after giving ketamine?
glycopyrrolate. It increases secretions
How does ketamine affect.... CMRO2 Cerebral blood flow ICP Intraocular pressure EEG activity
increases all
Why is ketamine contraindicated in eye surgery?
causes nystagmus
What is the best medication to give to prevent emergence delirium in a patient that received ketamine?
Midazolam before ketamine administration. Also diazepam
What are risk factors for emergence delirium from ketamine?
age > 15 years, females, ketamine dose > 2 mg/kg, hx of personality disorder
In order to prevent hyperalgesia following remifentanil infusion what IV induction agent can you give?
ketamine
Where does ketamine block central sensitization and wind up in the spinal cord?
dorsal horn
What can chronic ketamine use cause?
ulcerative cystitis
Ketamine should be avoided in what patient?
acute intermittent porphyria
Which IV induction agent undergoes the smallest amount of plasma protein binding?
ketamine
What is the chemical name and class of etomidate?
R-1-methyl-1-(a-methylbenzyl) imidazole-5-carboxylate Imidazole
How does an acidic pH and physiologic pH affect solubility of etomidate?
acidic pH: water soluble
physiologic pH: lipid soluble
What are the two formulations of etomidate?
35% propylene glycol: venous irritation and pain
lipid emulsion: less pain
What is the MOA of etomidate?
GABA-A agonist
What is the induction dose of etomidate?
0.2-0.4mg/kg