2nd test anestesio Flashcards
hx of ketamine
intoduced in 1970
syntheiitc drug (not derived from natural product - like propofol and benzos)
part of feniciclidina group
cx of ketamine
anesthetic agent - can be used unico for that
analgesia
not volatile
liposoluble derivative of fenciclidina
ketamine mechanism and action
not well understood
only EV that gives inhbition and excitation and simultaenously - selectively in one organ CNS (aka DISSOCIATIVE ANESTHESIA - keeps some reflexes intact and others depressed - other EV have to wait for px to close eyes not ketamine - produces fixed gaze tho scared - doesnt blockeyeball like oethers where eye rolls up - ketamine can cause nystagmus tho -)
excites limbic systrm, inc HR, VC, psychiatric deliriums (maybe resistant to others)
depresses cortex and thalamus
inetrrupts pain - anesthesia
blocks AcH at cortex
we think ketamine acts at same opiod rec due to reversal same
but also act in serotonin rec, NE rec, and muscarinic Ach rec
(@ muscarininc thats why salivation increases) -
maintain swallow reflex - px can cough, maintains suction reflex - defense mechanisms
@ NE rec liberates catecolamines, VC peripheral and increases BP
@acute processes dehydrated, hypotense state hypovolemic shock px give ketaine with anesthetic inductor helps cardiac precharge
produces hipnosis actina @ cortex BUT DIFFERENTLY and like barbs with excitation right before (not calm, agitated - unlike propofol)
analgesia > anesthesia –>
(need less inhaled gas) & (no pain at immediate postqx
antagonista puro de opiodes
naloxone
desireaed and undesired effects
FD ketamine
dissociative anesthesia ( suppresses some reflexes while others not)
maintains cough and corneal, suctionz
coordinated movements but not conciosu
eyes open, fixed gaze, nistagmus
potent hipnotic and analgesic
iincreases ICP
blood flow of brain
cerebral O2 cconsumption …metabolsm and intraocular pressure
can we measure depth of coma in ketamine
noooo
effect of ketamine on VC system
acts at NE rec and thats why it increases systolic arterial P 20-40mmHg - causes peripheralVC - more volume reaches heart (precharge) - CO increases as well
increases HR (increases LV work)) and O2 consumption of that muscle - so not good for px with coronary problems
elebates pulmonar vasc resistencees
relaxes bronquial SM - BD (@ asma px, BC px - ideaal_
secondary to increase in sympathetic activity
hepatic px (transplant px)are VD pysiologically, others VD from drugs (propofol, barbs, opiods) - ketamine ideal for VD px (NE causesVC)
anything that increases work of ventricle increases O2 consumption
not best in coronary px
BD (relaxes SM there)
ketamine @ resp
minimal effect - doesnt depress giving it biosecurity
problems alot of time when its used with another drug like opiods
transitory apnea < 5min
seen after intubation dose
relaxes broncial SM
betters pulm compliancy in anesthetic px
FK metabolism of ketamine
very liposoluble - used EV have effects in 1min
crosses BBB
duartion ketamine
10-15min (1min initiation)
IM effect by 5min (absorbs well)
produces qx anesthesia in 30-60sec
20 peak
oral dose produces max sedation in 20-45min
indications of ketamine
IV anesthetic inductor - can be alone
useful in hypovoelmic acute shock
good for kids - cardiac congenital (R to left), bronchial hyperactivity (BD)
used as inducgion agent in kids - IM
(before sevorane)
px with cardac tamponade
px with cardiac congenital diseases with right left shunt
px with reactive bronqual disease severe due to BD effect
useful in kids as an inducctor for less deliriums than in adults
IM inducer in px arent cooperating (with EV, studies)
can cause conscious sedation in kids that are doing minor procedures, como curas o cambios de apositos, desbridamiento of wounds, xray
IN these proceudres causes excellent analgesia wihtout respiratory depression
px that have to go everyday to get anesthesia for qxs
studies where we cant be in contact iwth px or px needs to be stilll/calm - CT, MRI, RT -good to canalize kid for short proceudres no resp or CV depresison
CI ketamine
px with ICP, mass in brain, cerebral infarct hx
NE rec @ chronic shock are depeleted so nooo, opposite effect , more VD (NE, epi wont work!)
px with open ocular lesions , glaucoma, (because ketamine increases intraocular pressure) ophtalmological qx
in px with coronary disease or pulm HTN, HTN,
in px with catecolamine depletion (in px with critical prolonged disease) - ketamine has
cardiodepressor effect which can manifest
bedridden px
px with psychiatric alteratiooncs - causes hallcuincations (auditive or visual), delirium
narcotrafficked, pleasure use-
ketamine interactions
potentiates relaxers NDNMRS
hipotension with halotane
prolongs inhaled anesthesia aka reduces CAM
dosis ketamine
IV
IM
recta;
oral
induction 0.5-2mg/kg IV (1mg/kg)
4-10mg/kg/IM (5 is enough)
maintenace 30-90mg/kg/min
10-20mg for concious sedation
benzodiazepines
dizepam, lorazepam, midazolan
preqx to sedate px - antianxiety
PROLONGED amnesia and good sedation - px wont remember
used in preanesthesia, preinduction, preqx to calm px down
EV anesthetics (right before qx)
also IM, VO (night before), parcho
NO ANALGESIA
NOT FOR INDUCTION OF SLEEP/ANESTHESIC
sturctures of benzos
diacepam and loracepam have similar structures
biodisposition diacepam
high liposoliblituy , hipofilic wait CNS initation
crosses BBB faster than midazolam (more hydrosoluble)
IM irritattes, hurts, acido bensoto, EV also irritates
somnolence, hipnosis slow irregular
very insoluble in water
slow initiaion - not ideal preinduccion
30min
slow recuperation
all EV decrease flow in hard organs
liver kidney bazo
all EV eliminate thru liver (benzos, opiods) - all prolonged if liver messed up…. except ketamine
keatmine doesnt decrease flow!!!!!! - can be used in px with pathologies of these organs
meatabolizes at liver (even at decreased flow or pathology, clears up well) eliminaeted life stays the same
metabolites of diacepam
3hidroxidicepan
oxacepan
dismetilodacepan
WITH sedative and pharmacological activity
like opiods , benzos use oxydation to metabolize
liver
duration of action of diacepam coorelates with these metabolites
in order for these metabolites to eleiminate undergo
2nd bioptransmformation to elimiante not oxidation this time , conjugation
forming acido glucoronico without farmacological activityg
fk DIACEPAM
1.5LT/k C - distribution volume
CLEARING 0.2-0.5CC/KG/MIN
ELIMINATION HALF LIFE 20-40hr
midazolan
most recent benzo
1995-97s
more soluble in water - less irritant via IM
fast initation action
effect on CNS fast
mx depresion > 1-3min
IM absorbs well - effect at less 30min
faster sedation
mech of action of all benzos (like opiods)
@ CNS potentiloze GABA in different areas,
rec of benzos of CNS @ cortex, black sustancia, hipocampo (these others are IIor presynaptic).. cerebelo (has postsynaptic aka type I rec) , medula espinal.
rec are post synaptic or presynaptic (so benzos can be type I or II))
increase clorine ion conductance in synapsis which hyperpolarizes cell - inhibitory
unlike barb, benz increases aperture o fCl- channels
frprnf on lovslxsyion
farmacological action of benzos
decrease necessity for inhaled agent
b/c they are sedatives
@ CV benzos..
depression of myocardium
increase HR