GENERAL ANAESTHETIC AGENTS Flashcards
Anaesthesia :
an – _______ ; esthesia - _______ = (reversible or irreversible?) loss of _______ to _______ stimuli
without ; sensation
reversible;response
noxious
General Anaesthesia: when anaesthesia is associated with _________________
General anaesthetic – a drug that brings about (reversible or irreversible ?) _________________ .
Administered by an _________________
Used to induce or maintain general anesthesia to facilitate surgery
loss of consciousness
reversible ; loss of consciousness.
anaesthesiologist
Stages of Anaesthesia
Stage I : __________
Stage II : __________, __________ behaviour – __________ state
Stage III : __________ anesthesia
Analgesia
Excitement ; combative ;dangerous
Surgical ; Medullary paralysis
Stages of Anaesthesia
Stage III : Surgical anesthesia
eyeballs
corneal reflex
pupils ; dilating ; muscle relaxation
abdominal ; dilated pupils
Anaesthesia is divided into 2
A and B
A is further divided into C and D
A- inhalational
B-Intravenous
C-halogenated
D-Non-halogenated
Balanced Anaesthesia= anaesthesia + _________ + _________ + _________ + _________
Muscle relaxation
Analgesia
Reflex abolition
Unconsciousness
Inhalational (General) Anaesthetic
Non halogenated
_____________
Halogenated hydrocarbons
_____________ _____________ _____________ _____________ _____________
Nitrous oxide
Halothane Isoflurane Desflurane Enflurane Sevoflurane
Background (History)
General anaesthesia was introduced into clinical practice in the ______ century
Started with the use of volatile liquids such as __________ and __________
19th
diethyl ether and chloroform.
_______________ limited the usefulness of chloroform (out of date!).
Cardiac and hepatic toxicity
Regimen for balanced anaesthesia
Pre-medication
________ for autonomic stabilization
________ for anxiolysis
________ for analgesia
Atropine
Diazepam
Pentazocine
Regimen for balanced anaesthesia
Induction
________ for unconsciousness
________ for muscle relaxation
________ for unconsciousness
______ for analgesia
————- for muscle relaxation
Midazolam
Succinylcholine
Halothane, NO2, Pancuronium
Regimen for balanced anaesthesia
Reversal
________ for reversal of neuromuscular block
________ for analgesia
Neostigmine
Pentazocine
The MAC is the _______________ of anaesthetic agent that produces ________ in ____% of patients exposed to a standard noxious stimulus.
minimum alveolar concentration
immobility
50
The ________ the MAC, the more potent the agent
LOWER
Arrange the Agents in order or increasing potency
Nitrous oxide
Desflurane
Sevoflurane
Enflurane
Isoflurane
Halothane
Methoxy-flurane
Factors that decrease MAC
_______thermia
_______ natremia
_______
_______ age
______ depressants (sedatives, analgesics, IV anaesthetics)
Severe _______
Severe _______
Hypothermia
Hyponatremia
Pregnancy
Old age
CNS depressants (sedatives, analgesics, IV anaesthetics)
Severe anaemia
Severe hypotension
Factors that increase MAC
_______thermia
_______natremia
CNS ___________ (e.g. amphetamine, caffeine)
Hyperthermia
Hypernatremia
CNS stimulants (e.g. amphetamine, caffeine)
Mechanism of action
Partial Pressure in _______ <= = => partial pressure in _______ <= = = > partial pressure in _______.
Brain; arterial blood
alveoli.
Mechanism of action
The DEPTH of anesthesia induced by an inhaled anesthetic depends primarily on the _____________ !!!
The ______________ determines the movement in and out of different compartments
The rate of induction and recovery from anesthesia of the anaesthetic in the brain is dependent on the rate of change of ________ in the ________.
PARTIAL PRESSURE
pressure gradient
partial pressure in the brain
LOW solubility in blood= ______ induction and recovery
HIGH solubility in blood= _______ induction and recovery
fast
slower
Factors that determine anaesthetic depth, (rapid induction and recovery) include
● _________ concentration
● alveolar _________
● _________ of anaesthetic in blood;
● _________ of anesthetic in tissues
● _________
● inspired concentration
● alveolar ventilation
● solubility of anaesthetic in blood;
● solubility of anesthetic in tissues
● cardiac output
The Ideal inhalational agent
________ odour
(Irritant or Non-irritant?) allowing pleasant and rapid induction
Pleasant ; Non-irritant
Low ; Chemically
anaesthesia circuit ; soda lime
Ideal inhalational agent
Capable of producing _________ , _________ and some _________
unconsciousness, analgesia and some muscle relaxation
high ; metabolised
-toxic ; allergic
depression ; CVS, RS.
other anaesthesia drugs ; inert.
Nitrous oxide
It is ____________
______ color and _____ odor
(Explosive or Non-Explosive?) and (Inflammable or Non-
Inflammable?)
_______ at room temperature and can be kept as a _______ under pressure.
Relatively (expensive or inexpensive?)
laughing gas
Colourless and odourless
Non-Explosive and Non-Inflammable
Gas ; liquid
inexpensive
Only inorganic anaesthetic gas in clinical use is??
Nitrous oxide
Nitrous oxide
CVS:
(Stimulate or Depress?) sympathetic nervous system.
Directly depresses ________________ .
Arterial blood pressure ,heart rate and cardiac output are slightly _____eased.
RS:
Increases _________ with decreases ___________
Minimal change in ________________
Stimulate ; myocardial contractility.
increased.
respiratory rate ; tidal volume.
minute ventilation
Nitrous oxide
CNS:
Increases ________ thus increasing ___________
Renal:
It _____eases renal blood flow thus leads to _____ in glomerular filtration rate and urinary output.
CBF ; intracranial pressure
decreases ;drop
Nitrous Oxide
Hepatic:
——-eases the Hepatic blood flow but to a (lesser or greater?) extent than other inhalation agents.
GIT:
It causes ______________________
Analgesia
* ________ anaesthesia as Entonox 50:50 Oxygen & Nitrous oxide)
Decreases ;lesser
Post operative Nausea and Vomiting (PONV)
Labour
Nitrous oxide
Advantages
nonflammable & non explosive
non-irritant potent analgesic
_________ onset, changes in depth and recovery
little or no _______ during normal application
very rapid
toxicity
Nitrous oxide
Disadvantages
______ anaesthetic agent
no augmentation of _________
____________ on recovery
Expansion of closed internal air-spaces
long term use in excessive quantity associated with ______________________ due to reduced haemopoiesis neuropathy , tinnitus , numbness
weak; muscle relaxation
diffusion hypoxia
Vit B12 deficiency anemia
Nitrous oxide
Contraindication of N2O
_________
____________
Acute_______________
Tension _____________
____________________ grafting
Airembolism
Pneumothorax
AcuteIntestinalObstruction
Tension Pneumocephalus
Tympanic membrane grafting
HALOTHANE
A halogenated hydrocarbon supplied as a ________ and is ________ for use as an inhalation anaesthetic
Used for __________ and __________ of anaesthesia
(Flammable or Nonflammable?) and (Explosive or Non explosive?).
Does not decompose in contact with __________
liquid ;vaporized
induction ; maintenance
Nonflammable ; Non explosive.
warm soda lime
Least expensive halogenated hydrocarbon agent is ??
Halothane
HALOTHANE
CVS:
Dose dependent reduction of arterial blood pressure by direct _____________ .
It is a coronary artery vaso_______
It causes __________ of SAN node conduction resulting in _______cardia
Sensitize heart to _____________ in presence of hypoxia & hypercapnoea
RS:
Causes ________,_______ breathing.
______ease in alveolar ventilation and Paco2 __________.
Potent broncho________.
CNS
It ______eases cerebral blood flow.
myocardial depression ; vasodilator
slowing ; bradycardia
catecholamines ; rapid ,shallow
Decrease ; elevated
bronchodilator.
CNS
It increases cerebral blood flow.
Halothane
NEUROMUSCULAR:
__________ skeletal muscle and _________ Non-depolarizing neuro-muscular blocking agents.
Renal:
__________ renal blood flow, glomerular filtration rate and urinary output.
Hepatic:
______eases hepatic blood flow.
Relaxes
Reduces
Decreases
Halothane
Contraindication:
Unexplained ______ dysfunction.
_________ mass lesions.
__________ patient with severe _______ diseases.
liver
Intra-cranial
Hypo-volemic
cardiac
Halothane Advantages
_________ potency, __________ blood:gas partition coefficient ®
induction and recovery not prolonged
______________ changes in depth of anaesthesia
relatively non-irritant & broncho______ ® laryngospasm & bronchospasm uncommon
____________ and ____________ in combination with O2
_____tensive effect sometimes desirable
uterine relaxation
moderately high; moderately low
moderately rapid; dilator
nonflammable & non explosive
hypo
Halothane disadvantages
only _______ is completely obtained ® require additional analgesia, muscle relaxation, etc.
______/__________- respiratory depression
Hypotension
transient __________ - especially with __________
increases the ___________ of the myocardium, and when combined with adrenergic agonists ® ectopic pacemakers
Safe dose for infiltration =___:________ ® 60 ml/hr, or 1 ml/min
sleep; hypoxia/hypercapnia
arrhythmias; adrenaline
automaticity
1:200,000
Isoflurane
maintenance.
Has a ________ smell hence usually not used for _________
(Flammable or Nonflammable?) & (explosive or non explosive?) in combination with O2
maintenance.
pungent ;induction
Nonflammable ; non explosive
Isoflurane
CVS
Causes minimal _____________
________ increase in MAC lead to increase in ______ and ______ .( Coronary ____)
________ coronary arteries.
RS
Respiratory depression
Acts as a good broncho_______.
CNS:
If conc > ___MAC causes increase in __________
cardiac depression
Rapid; HR and BP; Steal
Dilates; dilator
1
CBF and Intracranial pressure.
Isoflurane
N/MUSCULAR:
_________ skeletal muscles.
Renal:
_____eases renal blood flow, glomerular filtration rate and urinary output.
Hepatic
_________ hepatic blood flow
Relaxes
Decr
Reduces
Isoflurane Advantages
___________ potency, ___________ blood:gas partition coefficient
_______ induction of and recovery from anaesthesia , _______ changes in depth of anaesthesia
enhancement of muscle relaxation
incidence of arrhythmias is less than ___________
maintenance of _______ and lack of myocardial __________
minimal ___________
_______ controllable via PaCO2
moderately high; low
rapid ;rapid
halothane; CO ; depression
biotransformation ; ICP
Isoflurane
Disadvantages
a. _______ anaesthesia with
isoflurane ® respiratory & circulatory _________ . hypoxia /hypercapnia/hypotension
b. _________ odour and initial respiratory _________
c. possible _________ syndrome with _________ in IHD
d. uterine relaxation contraindicated at _________
e. more _________
deep ; depression
more pungent ; irritation
subendocardial steal ;hypotension
parturition; expensive
Isoflurane
CONTRAINDICATION
Patient with severe ________ may not tolerate its vasodilating effects.
hypovolemia
Desflurane
Highly __________ __________ _________
ether
Used for __________ of general anaesthesia
Like halothane, enflurane, and isoflurane, it is a racemic mixture of (R) and (S) optical isomers (enantiomers)
Recovery time are approximately ____ % less than those of Isoflurane
fluorinated methyl ethyl ether
maintenance
50 %
Desflurane
CVS
Similar to _________ (____eases HR and BP when increased MAC rapidly)
________ coronary arteries.
RS
Causes decrease in __________ and increase in __________
Pungent and airway irritation so causes __________ and sometime __________
Isoflurane ; increases
Dilates ; tidal volume
resp rate.
coughing ; bronchospasm
Desflurane
NEUROMUSCULAR:
________ skeletal muscle.
Renal & Hepatic Sys:
_______________ has been documented.
Relaxes
No any evidence
Desflurane
Contraindication
Severe ___________.
________ _____tension.
________ ________.
Severe hypovolaemia.
Intracranial hypertension. Malignant hyperthermia.
Sevoflurane
Sevoflurane is an ________ inhalation anaesthetic agent used for the ________ and ________ of general anesthesia.
A ________, (flammable or non-flammable?) , (irritant or non- irritant?), and _____-to-administer compound with a ______ solubility profile and blood-to-gas partition coefficient.
Induction and recovery is ______.
It is _______ smelling and pleasant.
It does not cause irritation of the airway
ether
induction and maintenance
A volatile, non-flammable, non- irritant
easy; low ; fast.
sweet
Sevoflurane
CVS: (Mildly or Severely?) depresses myocardial contractility
RS: ________ respiratory rate. It ________ bronchospasm
Renal: _________ renal blood flow. Higher Conc Causes ___________
CNS: Increases ________ and _____________ pressures
Mildly; Depresses; reverses
Slightly decreases
Nephro-toxicity
CBF and intra-cranial
Sevoflurane
Renal: Slightly ______eases renal blood flow. Higher Conc Causes __________
Hepatic: _______eases portal vein blood flow but _____eases hepatic artery blood flow thus maintaining total hepatic blood flow.
N/Mslar: _________ muscle relaxation.
decr; Nephrotoxicity
Decr; incr
Adequate
Sevoflurane
Advantages
it has a ________ odour
________ induction & emergence
highly suitable for ________ anaesthesia
pleasant
very rapid
paediatric
Sevoflurane disAdvantages
(Cheap or Expensive?)
unstable in _________, however, metabolites are apparently ________
Expensive
soda-lime; non-toxic
Sevoflurane
Contraindication
List 3
Severe hypovolaemia.
Intracranial hypertension.
Malignant hyperthermia.
Ether
W.T.G Morton on 16th Oct 1846 used for removal of ________.
________ smelling ________, that ________ in presence of light, air, heat.
Highly _________ and ________
Highly ________ vapour.
Very (Cheap or Expensive?) .
Also called as _________ Anaesthetic agents
jaw tumor; pungent
Liquid ; decomposed
inflammable and explosive.
Irritant ; cheap; Complete
Ether
Induction very _______, ________ smells and may causes ___________
Very good ____________
Very good ______________
slow; pungent
laryngeal spasm; analgesic.
muscle relaxants
