Isoflurane

PROPERTIES:
  • Widely used now, an isomer of enfllurane & desflurane colorless, less soluble, nonflammable, stable, mild pungent odor, MAC 1.5%
PHARMACODYNAMICS:
  • Lungs: mostly exhaled as such
  • Heart: lesser effects, does not sensitizes,
  • Liver and Kidney: not injurious.
  • General information:
  • Approved in 1985 for veterinary practice
  • Not a convulsive agent
  • Malignant hyperthermia in swine reported
  • Adequate muscle relaxation
  • Rapid and smooth induction
  • Isoflurane has Least effect on myocardial contractility & is Least Cardiotoxic 
  • Isoflurane is Pungent volatile anesthetic agents 
  • Rapid and smooth recovery
  • Due to minimal hepatic metabolism resulting in very low levels of inorganic fluorides 
  • In Myocardial Infarction operation should be with held for 6 months
  • Goldman Index is for cardiac risk factor and when it is > 13 it is associated with poor prognosis.
  • In hypertension, halothane is AOC (for hypotensive surgery)
  • Of various inhalation agents available, isoflurane has the advantage of providing stability of cardiac rhythm & lack of sensitizention of the heart to exogenous & endogenous adrenalineQ.
  • In ischemia of cardiac muscle selective vasodialation of vessels of Ischemic zone and maintained tone of non ischemic zone //t selective increase of blood supply to ischemic areas.
  • In hypovolumia, Light G.A. (preferably Ether and Cyclopropane) with IPPV is method of choice
  • Of various inhalation agents available, isoflurane has the advantage of providing stability of cardiac rhythm & lack of sensitizention of the heart to exogenous & endogenous adrenaline
  • In coronary artery disease isoflurane should be avoided Wt coronary steel phenomenon
  • In ischemia of cardiac muscle selective vasodialation of vessels of Ischemic zone and maintained tone of non ischemic zone selective increase of blood supply to ischemic areas.
  • But in coronary steal phenomenon (Isoflurane & Dipyridomole) there is dialation of vessels of non ischemic zone also so there is decrease of flow in ischemic zone. That is why isoflurane is avoided in ischemic heart disease.
USES:
  • Renal failure:Because of its low cardiac arrythmogenicity isoflurane is an ideal agent for patients with renal failure.
  • Isoflurane inhalational agent is used in patients with raised intra cranial tension
  • Isoflurane increases ICT but less than halothane & enflurane; which can be reversed by hyperventilation. So isoflurane is a preferable agent in raised ICT. 
  • Isoflurane is anaesthesia of choice (AOC) for neurosurgical procedure as it does not increase cerebral blood flow & CSF pressure.
  • Isoflurane increases ICT but less than halothane & enflurane; which can be reversed by hyperventilation. So isoflurane is a preferable agent in raised ICT. Isoflurane is
  • anaesthesia of choice (AOC) for neurosurgical procedure as it does not increase cerebral blood flow & CSF pressure. 
  • In Coronary artery bypass grafting surgery maintenance of anaesthesia is achieved by Isoflurane 
  • Alcohlic liver faliure requires general anesthesia AOC 
ADVERSE EFFECT:
  • In coronary artery disease isoflurane should be avoided Wt coronary steel phenomenon
  • But in coronary steal phenomenon (Isoflurane & Dipyridomole) there is dialation of vessels of non ischemic zone also so there is decrease of flow in ischemic zone.That is why isoflurane is avoided in ischemic heart disease.
Exam Question
  • Isoflurane is the anaesthetic agent of choice in renal failure
  • Isoflurane inhalational agent is used in patients with raised intra cranial tension
  • Isoflurane is Pungent volatile anesthetic agents 
  • Fluoride content is least in Isoflurane
  • Isoflurane has Least effect on myocardial contractility & is Least Cardiotoxic 
  • Desflurane is a structural analogue of isoflurane 
  • In Coronary artery bypass grafting surgery maintenance of anaesthesia is achieved by Isoflurane 
  • Alcohlic liver faliure requires general anesthesia AOC isoflurane

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