GENERAL ANAESTHETIC AGENTS Flashcards by Iseoluwa Ojo

Anaesthesia :

an – _______ ; esthesia - _______ = (reversible or irreversible?) loss of _______ to _______ stimuli

without ; sensation

reversible;response

noxious

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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

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Stages of Anaesthesia

Stage I : __________
Stage II : __________, __________ behaviour – __________ state
Stage III : __________ anesthesia

Analgesia

Excitement ; combative ;dangerous

Surgical ; Medullary paralysis

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Stages of Anaesthesia

Stage III : Surgical anesthesia

eyeballs

corneal reflex

pupils ; dilating ; muscle relaxation

abdominal ; dilated pupils

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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

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Balanced Anaesthesia= anaesthesia + _________ + _________ + _________ + _________

Muscle relaxation
Analgesia
Reflex abolition
Unconsciousness

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Inhalational (General) Anaesthetic

Non halogenated
_____________

Halogenated hydrocarbons
_____________ _____________ _____________ _____________ _____________

Nitrous oxide

Halothane Isoflurane Desflurane Enflurane Sevoflurane

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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.

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_______________ limited the usefulness of chloroform (out of date!).

Cardiac and hepatic toxicity

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Regimen for balanced anaesthesia

Pre-medication

________ for autonomic stabilization

________ for anxiolysis

________ for analgesia

Atropine
Diazepam
Pentazocine

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Regimen for balanced anaesthesia

Induction

________ for unconsciousness

________ for muscle relaxation

________ for unconsciousness
______ for analgesia
————- for muscle relaxation

Midazolam
Succinylcholine
Halothane, NO2, Pancuronium

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Regimen for balanced anaesthesia

Reversal

________ for reversal of neuromuscular block

________ for analgesia

Neostigmine

Pentazocine

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The MAC is the _______________ of anaesthetic agent that produces ________ in ____% of patients exposed to a standard noxious stimulus.

minimum alveolar concentration

immobility

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The ________ the MAC, the more potent the agent

LOWER

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Arrange the Agents in order or increasing potency

Nitrous oxide
Desflurane
Sevoflurane
Enflurane
Isoflurane
Halothane
Methoxy-flurane

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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

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Factors that increase MAC

_______thermia
_______natremia
CNS ___________ (e.g. amphetamine, caffeine)

Hyperthermia
Hypernatremia
CNS stimulants (e.g. amphetamine, caffeine)

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Mechanism of action

Partial Pressure in _______ <= = => partial pressure in _______ <= = = > partial pressure in _______.

Brain; arterial blood

alveoli.

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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

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LOW solubility in blood= ______ induction and recovery
HIGH solubility in blood= _______ induction and recovery

fast

slower

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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

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The Ideal inhalational agent

________ odour
(Irritant or Non-irritant?) allowing pleasant and rapid induction

Pleasant ; Non-irritant

Low ; Chemically

anaesthesia circuit ; soda lime

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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