INTRAVENOUS ANAESTHETIC AGENTS Flashcards
What are IV Anaesthetic Agents / Induction drugs?
These are drugs that, when given intravenously in an appropriate dose, cause a __________________________.
Often described as occurring within “________________________________ time”
rapid loss of consciousness
one arm-brain circulation
One-arm brain circulation time
that is simply the time taken for ____________________________________________ , where they have their effect; normally ___________
the drug to travel from the site of injection (usually antecubital) to the brain
10 -20 secs
Properties of an ideal IV induction drug
Physical / Chemical properties
• _________-soluble & _________ in solution
•(Cheap or Expensive?)
• Stable on exposure to ______
• ________ shelf-life
• No ________ on intravenous injection
• Not painful when injected into _________
• _________ when injected subcutaneously
• Low incidence of _________
• Water ; stable
Cheap; light
Long; No pain; an artery
Non-irritant ; thrombophlebitis
Properties of an ideal IV induction drug Pharmacokinetic properties
•_____________ in one arm-brain circulation time
•_________________ to vessel rich tissue
• Rapid __________ and ————-
• No _____________
Rapid onset
Rapid redistribution
clearance and metabolism
active metabolites
Properties of an ideal IV induction drug
Pharmacodynamic properties
• _______________ ratio (ratio of ________:____________ dose)
• Minimal ___________ and ————- effects
• No _________________/___________ reactions
High therapeutic
toxic dose : minimally effective
cardiovascular and respiratory
histamine release; hypersensitivity
Properties of an ideal IV induction drug
Pharmacodynamic properties
• No _________ effects
• No _____________ movements
• No emergence __________
• No ________ effect
• No ___________ ____________
• Safe to use in ________
emetic; involuntary
nightmares; hang over
adrenocortical suppression
porphyria
List 2 ideal Intravenous Anaesthetic agents
There is however No ideal Intravenous Anaesthetic agent.
Intravenous anaesthetic agents
Advantages
• rapid and smooth ________ of anaesthesia
• little ________ requirement (syringes, needles, catheters)
•easy _____________ of drugs
induction
equipment
administration
Intravenous anaesthetic agents
DisAdvantages
•difficult ________________ once administered
• less control of _________________ of anaesthesia
•lack of ____________ support
•poor tolerability in ________,___________, or ____________ individuals.
retrieval of drug
depth and duration
ventilatory
debilitated, dehydrated or toxic
Classification
A. Rapidly Acting (1o) Induction agents
__________
__________
__________ Compounds
__________
Barbiturates
Alkyl phenols
Imidazole Compounds
Eugenols
Classification
A. Rapidly Acting (1o) Induction agents
Barbiturates -3
Alkyl phenols-1
Imidazole Compounds-1
Eugenols -1
Methohexital
Thiopental Thiamylal
Propofol
Etomidate
Propanidid
__________ rapidly acting (1•) induction agent has been withdrawn from market
Propanidid- withdrawn from market
Slower Acting (___________) agents
__________ derivatives
__________
__________
basal narcotic
Phencyclidine
Benzodiazepines
Opioids
Slower Acting (basal narcotic) agents
Phencyclidine derivatives
___________
Benzodiazepines
_________ , _________
Opioids
_________, _________, _________, _________
Ketamine
Diazepam Midazolam.
Fentanyl Alfentanil Sufentanil morphine
General uses of IV anaesthesia agents
As __________ agents
__________________ (TIVA)
________ Sedation
________ to ________ Anaesthesia ________
________ protection
________ therapy
Induction
Total IntraVenous Anaesthesia
ICU Sedation
Supplement ; Regional Anaesthesia Anticonvulsant
Brain protection
Electroconvulsive therapy
TIVA- both ________/_________ of anaesthesia
ICU Sedation: _________,_________
Anticonvulsant: _____,__________
Brain protection: ___________ ( causes reduced ________ )
Electroconvulsive therapy esp. _________ preferred to __________
Induction/Maintenance
Propofol,Midazolam
STP, midazolam
Propofol; CMRO2
methohexithal; propofol
Most commonly used iv induction agent is ????
Thiopentone
A thiopentone
thio____________
Physical properties:
_______ powder, (soluble or insoluble?) in water with PH of ____, PKa of 7.6 Solution not stable for > ______ after reconstitution in _____ to a 2.5%
Best prepared fresh
barbiturate
Yellow ; soluble
10.8 ; 24 hrs
water
A thiopentone
Mode of Action
Act primary at synapses by depressing _____________ to _____________ and inhibit ____________________
post-synaptic sensitivity to neurotransmitters
pre-synaptic neurotransmitter release
A thiopentone
Administration-
Dose:____ route ____mg/kg
Onset time; _________________ time
DOA: _____________,
Repeated doses effect is ___________
Other route- ________, onset time is within _________
iv; 3-7
one arm-brain circulation
5-15 mins
cumulative; rectally; 15 mins
Thiopentone
Systemic Effects
CVS- ______ (By ____%), _______ leading to _________tension
Resp. Sys – __________ resp centre, ± ________
Reduces resp centre’s response to _______.
Histamine release may lead to ___________
CNS- _________→ __________ .
Anticonvulsant, ↓_____,_____,______
Skin- ___________ around neck
and chest occasionally
↓CO; 20; ↓PVR; hypotension
Depresses; apnoea; CO2
bronchospasm
depressed; hypnosis
CBF, ICP, IOP
erythematous rash
Thiopentone
Metabolism
________- main site, @ rate of ______% per hr.
_______% remain in body after 24 hrs.
(Active or Inactive?) metabolites excreted mainly in the ________ , 0.5% excreted unchanged
Liver; 10-15
30; Inactive
urine
Thiopentone
Contra-indications
Severe __________ or __________
Previous __________
Acute __________ __________
Acute __________ __________
Severe hypotension or shock
Previous anaphylaxis
Acute intermittent porphyria
Acute bronchial asthma
Thiopentone
Extravascular injection → _________
Inadvertent intra-arterial injection → arterial ______, __________ → __________ of e.g. the hand
Mgt:___________ in the artery, Flush with ________, Inj . _________ to relieve spasm, Keep the hand ______, _______ it, ± anticoagulant therapy
severe pain
spasm; thrombosis; gangrene
leave needle; saline
procaine; warm; elevate
Ketamine
A ___________ derivative
• Widely used as ________ in developing
countries
Enjoys wider use in _______ because of less post- anaesth effects
Available as ________________- 1%, 5% soln.
phencyclidine; TIVA
children
colorless solution
Ketamine
Main action- __________ anaesthesia (combination of ___________ with ______________ i.e. _____________). ________,__________ reflexes are preserved
Dissociative
profound analgesia with superficial sleep
light hypnosis
Gag, eyelash
Ketamine
Administration-
Iv dose-____ mg/Kg, onset time within _____, DOA of ________
im dose-______ mg/Kg, onset time within __________, DOA of ____________
Other routes- ______,_______,_________,__________
1-2; 1 min; 5-10 mins
5-10; 5 mins; 10-20 mins
orally, intrathecally, rectally, nasally
Ketamine
Systemic Effects
•
– CVS- ____SBP,DBP, ——-PR,→____CO
Resp system- ______ stimulation, with ————- of airway reflexes but _______ still possible. Broncho__________.
CNS- _____ CBF, CMR, IOP. _____ ,______ . State of ________ Anaesthesia.
GIT- _____mucous secretions including salivation, _____ Post-op. nausea and vomiting.
Others- ______ uterine tone.↑ Adr, and Noradr, circ. Levels
↑; ↑; ↑
mild; preservation; aspiration; dilatation
↑; Amnesia, Analgesia; Dissociative
↑; ↑; ↑
Ketamine
Metabolism- occurs in ______; excreted in ________
Liver
Urine
Ketamine
Clinical importance-
Good _________ and ________
Potent _________ effect
Can be used as _____ anaesthetic agent, ______ for many surgeries
Anaesthesia in ________,_____________ , LMIC
CVS and RS stability
Analgesic; sole; TIVA
war zones ,burn dressing
KETAMINE
Disadvantages
•Slower ———— time
•Slower _________
•Poor ___________
•Unpleasant __________,________
induction; recovery
muscle relaxation
dreams, hallucinations,
emergence delirium from ketamine can be reduced by premedication with _______,_________,__________
diazepam, midazolam, lorazepam
Ketamine
Contra-indication
•_______tension
•___________ disturbance
Hyper
Psychiatric
Propofol.
A ________ derivative: 2,6-diisopropylphenol
Presented as _________-in-water emulsion containing
1% (10 mg/ml, common) or 2% propofol in soybean,
purified egg phosphatide, and sodium hydroxide.
No preservative, good culture medium for bacteria
phenol
white oil
Propofol
The onset of its action begins after ______
After a single dose patient recovers after ________ with a _______ head and _____ hangover.
30 s.
5 min
Clear; no hangover
Administration of Propofol
•For induction: iv bolus _________ mg/Kg, with onset time of ______, DOA ________ after a single dose
•For maintenance: infusion of _______ mg/Kg/hr
For Children: ↑doses above by _____% for induction, and by _______% for maintenance
1.5-2.5
30 secs; 10 mins
4-12 ; 50; 25- 50
Propofol
Effects
CVS: ____ BP, ___ SVR→____ CO by ____ %, without ____________ . Attenuates haemodynamic response to laryngoscopy
Rapid bolus injection may cause _________ and __________
RS: ________ with rapid bolus, suppression of ________, depresses ventilatory response to _________,____________ . Broncho_________.
↓; ↓; ↓; 20; reflex increase in HR
bradycardia and asystole
apnoea; laryngeal reflexes
hypercarbia and hypoxia
dilatation
PROPOFOL
CNS: ______,______ induction with _______ and ————- recovery.
-_____ ICP, CPP, CMRO2, beneficial in __________.
GIT: intrinsic __________ properties
Others- free radical scavenger,
Long term infusion (>48hrs) may lead to _______________ , and ↑ mortality esp. in __________
Causes ——— on injection, may be reduced by Addition of ________, _______ the drug, or use of ____________
smooth, rapid
rapid and clear-headed ; ↓; neurosurgery
anti-emetic ; hypertriglyceridaemia
children in ICU; pain; Lidocaine; cooling; large veins
Propofol
Metabolism- mainly in ______ to (active or inactive?) __________ + other extra hepatic clearance. Metabolites, and small unchanged form excreted in urine
Renal and Hepatic disease have NO clinically significant effect on metabolism
Liver; inactive glucoronide
Propofol
Contraindications- ______, untreated __________, ______tension pts
Shock
hypovolaemia
hypo
Ketofol (mixture of ________ and _________ )
Different concentrations(____,____,____,_____)
Some studies have been done to show efficacy of the combination in procedural sedation.
ketamine and propofol
1:1, 1:2, 1:3, 1:4
Midazolam
A water (soluble or insoluble?) ________-________
(Mildly or Highly?) protein bound, ______%
Presentation- ________, ________ solution
soluble ; Imidazo-benzodiazepine
Highly ; 97%
clear, colorless
Midazolam
Main actions
Hypnosis- iv ________
__________
___________
__________ amnesia
Anticonvulsant
___________
induction; Sedation
Anxiolysis; Anterograde
Muscular relaxation
Midazolam
Administration
_____________/sedation:
im/iv dose :_____ mg/kg _______ pre-induction
Induction dose: iv- ________ mg/kg onset time within ______, DOA _________
Other routes- intrathecal, epidural, oral ( ________/__________)
Premedication
0.05-0.1; 30mins
0.2-0.3; 2-3 mins
10-15 mins
sweetened/ flavored
Midazolam
Effects
CVS: ____BP,____ SVR, but _______ PR lesser than propofol, thiopentone, hence produces _____________ haemodynamics
RS: impairs respiratory response to ________, respiratory _________, ______ may occur
CNS: ____ CBF, ____ CMRO2→ ____ ICP- brain protection against ischaemia
↓; ↓; reflex ; reflex ↑
relatively stable
hypercapnoea; depression; apnoea
↓; ↓; ↓
Midazolam
Metabolism- occur in _____, excreted in _______.
-termination of action of single dose is due to _____________ from _______ to ___________
Liver; urine
re-distribution
brain ; peripheral tissues
