Flashcards in propofol Deck (30)
what is the classification of propofol?
what is the equilibration 1/2 time of propofol?
what are uses of propofol?
-induction and maintenance of general anesthesia
-combine with sedation and regional anesthesia
-adjunct for MAC or TIVA
what is the MOA of propofol?
inhibits neuronal activity at the post synaptic GABA receptors by increasing chloride conductance into cell
-GABA's natural function is to reduce activity of neurons
-acts via ion mediated receptors (chloride): chloride influx increased, preventing depolarization
*hyperpolarization of post synaptic membrane inhibits neuronal activity
*gives desired hypnosis and sedation effects
describe onset of propofol
-rapid onset of action d/t high lipid solubility
describe metabolic clearance of propofol
-short half life: 2-8 min of initial dose
-30-60 ml/kg/min cleared (changes if hepatic blood flow altered)
-metabolites excreted renally (but renal failure does not affect clearance of parent drug)
when should propofol not be given in relation to clearance?
-absolutely no urine output
*can be given with renal failure
what are CV effects of propofol?
-decrease in arterial BP r/t drop in SVR (elderly, speed of injection, large doses)
-vagal like effects (drop in HR & BP) can lead to asystole,
what increases the risk of asystole or other hemodynamic instabilities occurring with propofol?
-prone to oculocardiac reflex (aka vagal ocular reflex)
*eyes surgery, visceral/peritoneal tugging
-pre-existing impair ventricular function (significant drop in CO)
*decreases ventricular filling pressures
*SVR= (MAP-CVP)/CO x 79.9
what are respiratory effects of propofol?
-profound ventilator depressant (apnea after induction doses and sometimes after sedation doses)
-inhibits hypoxic drive (normal response to hypercarbia is altered)
-upper airway reflexes are depressed more than with thiopental
*great for use with LMA and intubation (no spasm)
-some histamine release but less than barbiturates and ketamine (don't use in asthmatics with ACTIVE bronchospasm or wheezing)
*can give to asthmatics with no s/s of constriction
*large doses used with status asthmaticus, rationale being large dose will overcome bronchospasm
what are neurologic effects of propofol?
-decreases ICP and CBF
-significant drop in CPP (MAP-ICP) with elevated ICP
*normal 80-100 mmHg
*critical reduction of CPP (< 50 mmHg
*sustained CPP <25 results in irreversible brain damage
-suppresses memory by inhibition of post-synaptic neurons
-decrease intraocular pressure
-excitatory phenomena (muscle twitiching, spontaneous movement, hiccups) YET breaks status epilepticus
*avoid use in pts with known seizure hx (not contraindicated)
*predominant anticonvulsant effects
what are some drug interactions with propofol?
-old formulations potentiated actions of NDMBs (newer do not)
-slight synergistic effect with midazolam
-opioids have faster onset and total dose required may be lower
-asystole episodes increased with opioids
what are contraindications of propofol use?
-egg and soybean allergies (not true contraindication, but caution and avoid if can)
-not approved for OB use
-markedly increased ICP
-avoid in severe CAD pts. (hypotension)
-not approved for pediatric ICU sedation
-some newer formulas may contain sulfites (sulfa allergy)
-prior sensitivity or unexplained reaction to propofol
-inexperienced airway management personnel
-rapid bolus in the elderly and debilitated
describe important sterile technique with propofol use
-composition supports bacterial growth
-administration should be completed within 6 hrs
*death and severe sepsis has been associated with contamination
*ampules should be used within 6 hrs even if containing sulfites
what are complications of propofol?
-pain on injection: changes in pH from preservatives
-allergic reactions (allergy to NMB increases)
-seizure activity (should consider it an allergy)
-infection from contamination (supports growth of E.Coli and Pseudomonas A. and Candida A)
-introvert to extrovert behavior
what should be done to help pain on injection with propofol?
-sedation/versed as well as opioids help to reduce pain
what are certain triggers associated with propofol induced seizures?
-epileptic history or family history
-history of prior propofol admin
-allergy to NDMB
-history of chemical dependency
-heightened emotional state prior to surgery
-presence of hyperventilation or fever
-fast rate of propofol admin
what are primary benefits of propofol?
-antiemetic (inhibits CTZ)
-decreased airway reflexes especially upper airway
-may help with pruritis
-break status epilepticus
what is the general induction dose of propofol?
what is the induction dose of propofol for healthy adults?
what is the induction dose of propofol for elderly or debilitated pts.?
0.5-1.5 mg/kg over 30+ sec
what is the induction dose of propofol for cardiac and neuro cases?
cardiac: 0.5-1.5 mg/kg
neuro: 1-2 mg/kg
what is the induction dose of propofol for pediatrics?
2-3 mg/kg over 20-30 sec
what is the initial dose of propofol for a MAC case?
0.5 mg/kg in a healthy adult
*reduce in 1/2 for elderly and debilitated
what is the dose of propofol for ICU maintenance of a ventilated pt.?
-initial: 0.3-0.6 mg/kg/hr and titrate
-additional 10-20 mg boluses as needed
what is the MAC propofol infusion rate for mild, moderate, and heavy sedation cases?
mild: 25 mcg/kg/min
moderate: 50 mcg/kg/min
heavy: 75-100 mcg/kg/min
compare propofol to thiopental and ketamine
-rapid onset and quick clearance
-can be used for maintenance
-potential to induce seizures
-pain on injection
-more seizure protective
-more organ protective (brain)
-slower awakening time and longer sedative effects
-less pain on injection
-some histamine release
-increased sleep time (than propofol)
-contraindicated in seizures, spinal cord, and brain injury, significant cardiac disease, and hypermetabolic states
-reduced respiratory depression
-less pain on injection
describe fospropofol (Aquavan)
-prodrug of propofol
-not approved for general, but approved for sedation/MAC cases
-takes more drug than propofol to produce same effect to loss of consciousness
-delayed time to peak concentrations, wake up may be delayed
what is fospropofol metabolized to?
-propofol, formaldehyde, phosphates
*formaldehyde: carcinogenic; however, the amount present is said to be scant and equivalent of that present after other drugs are metabolized