Inhalational agent of choice for induction of anesthesia in Children?
Ans. a (Sevoflurane) (Ref. Anaesthesia by Ajay yadav 3rd ed., p 65)SEVOFLURANE# Chemistry and Physical Properties- It is nonflammable and nonexplosive in mixtures of air or oxygen.- Care must be taken to ensure that sevoflurane is not used with an anesthesia machine in which the CO2 absorbent has been dried by prolonged gas flow through the absorbent.- Sevoflurane reaction with desiccated CO2 absorbent also can produce CO2 which can result in serious patient injury.# Pharmacokinetics- rapid induction of anesthesia, and rapid emergence following discontinuation of administration.- Sevoflurane is metabolized in liver by CYP2E1 & predominant product being hexafluoroisopropanol,# Clinical Use- Sevoflurane is widely used, particularly for outpatient anesthesia, because of its rapid recovery.- Suited for inhalation induction of anesthesia (particularly in children) as it is not irritating to airway.- It the most effective clinical bronchodilator of the inhalational anesthetics.- Unlike isoflurane or desflurane, sevoflurane does not produce tachycardia and thus may be a preferable agent in patients prone to myocardial ischemia.# Side Effects- Hypotensive effect- Sevoflurane produces effects on cerebral vascular resistance, cerebral metabolic O2 consumption, and cerebral blood flow that are very similar to those produced by isoflurane and desflurane.- Biochemical evidence of transient renal injury has been reported in human volunteers.- It is not known to cause hepatotoxicity.AnestheticSolubilityMAC (%)Metabolism (%)Unique side effects/propertiesNitrous oxide0.5>1000Low potency; because the MAC is >100, it cannot provide com plete anesthesia; good for induction; good anesthesia and amnesiaDesflurane0.46.5<0.1Pulmonary irritantSevoflurane0.72.03-Isoflurane1.41.30.2-Enflurane1.81.78ProconsultantHalothane2.30.820Halothane hepatitis; sensitizes heart to arrhythmogenic effects of catecholaminesMethoxyflurane120.2>70NephrotoxicityOil: gas partition approx. = 150 + MACEducational point:# Fluoride ion liberation - M >> S >> E >> I > D.# Desflurane is a strong airway irritant, and can cause coughing, breath-holding, laryngospasm, and excessive respiratory secretions. Because of its irritant properties, desflurane is not used for induction of anesthesia.
Sevoflurane
Enflurane
Isoflurane
Halothane
General Anesthesia