Sevoflurane

Sevoflurane  REF: Morgan’s anesthesia 3″ ed p. 404, 570, 860, 884

“Sevoflurane is anesthetic of choice for induction in pediatrics because of rapid onset and non-pungency”

Induction in pediatrics patient

• Inhalation — Sevoflurane in N20
• Intravenous (preferred) – rapid acting barbiturate like thiopental or Propofol followed by non-depolarizing muscle relaxant.
• Intramuscular- Ketamine
• Muscle relaxant (MR)- Rocuronium

Sevoflurane

Ans:A.)Desflurane.

• Sevoflurane,Enflurane and Isoflurane have Epileptogenic potential.

Intracranial pressure is increased at high inspired concentration of sevoflurane but this effect is minimal over the 0.5-1MAC range.

Sevoflurane is considered to be the inhalational induction agent of choice in children,

since it has a pleasant, faster, and smooth induction with no significant systemic toxicity.

Sevoflurane is the induction agent of choice in pediatric anaesthesia.

It is associated with little mayocardial depression or dysrhythmias.

It has specific advantages over halothane when used in children with CHD,

particularly in children younger than 1 year of age and in cyanosed children.

It does not cause reduction in heart rate.

Inhalational Anaesthetics

Features of Liquid Inhalational Anaesthetic agents:

Since this patient gives a history of malignant hyperthermia during previous surgery,

sevoflurane is contraindicated in this patient.

Drugs known to precipitate malignant hyperthermia are succinylcholine, halothane, isoflurane, desflurane and sevoflurane.

Ref : Essentials of Medical Pharmacology By K D Tripathi 5^th edn, page 340.

Ans. is ‘b’ i.e., Sevoflurane

 “Unlike desflurane, sevoflurane poses no problem in induction, acceptability is good even by pediatric patients”.

D i.e. Sevoflurane

1. The greater the uptake of anesthetic agent, the greater the difference between inspired and alveolar concentrations, and the slower the rate of induction.
2. Three factors affects anesthetic uptake: Solubility in the blood, alveolar blood flow and difference in partial pressure between alveolar gas and venous blood.
3. Many of the factors that speed induction also speed recovery: elimination .of rebreathing, high fresh gas flows, low anesthetic circuit volume, low absorption by the anesthetic circuit, decreased solubility, high cerebral flow, and increased ventilation.
4. Because the concentration of a gas is directly proportional to its partial pressure, the alveolar partial pressure will also be slow to rise. The alveolar partial pressure is important because it determines the partial pressure of anesthetic in blood and, ultimately, in the brain. Similarly the partial pressure of anesthetic in brain is directly proportional to its brain tissue concentration, which determines clinical effect.
5. v.   Blood gas partition coefficient (B/G Coff.) is most important factor in determining the uptake of agent and so the speed of induction and recovery. The higher the B/G coefficient of an anesthetic, the greater its solubility in blood and its uptake in pulmonary circulation. As a result of this alveolar partial pressure rises much slowly & induction is prolonged. Agents with low blood gas partition coefficient will have high alveolar concentration. So the induction & recovery will be fast with agent with less B/G Coff.; and induction and recovery will be slower with agents with high, B/G partition coefficients. Q
6. Agents in increasing order of B/G coefficients (or decreasing order of induction & recovery)

I Xe (0.14) Desflurane (0.42) > Cyclopropane (0.44) > N₂0 (0.47) > Sevoflurane (0.69) > Isoflurane (1.38) > Enflurane (1.8) > Halothane (2.4) > Chloroform (8) > Trielene (9) > Ether (12) > Methoxyflurane (15)

B i.e. Sevoflurane

A i.e. Sevoflurane

D. i.e. All of the above

D i.e., Sevoflurane is less cardiodepressant than isoflurane

Sevoflurane is inhalational agent of choice for inductioin of anesthesia in pediatric patients and adults, because of rapid onset of action & nonpengency Q

Desflurane & isoflurane are more pungent and are associated with more coughing breath holding & laryngeal spasm during inhalational inudction, so not used as first choiceQ.

Methoryflurane is highly nephrotoxic, so not preferred.

Sevoflurane is not recommended in closed circuit because there is chance of production of a toxic metabolic product compound A, Q (an olefin) in closed circuit.

–  Unlike isoflurane & desflurane, both of which lead to tachycaridia, sevoflurane has minimal effect on heart rate.

Sevoflurane can cause direct myocardial depression (via calcium channels) and produce dose dependent depression of cardiac output, & reduction in systemic vascular resistance similar to that seen in isoflurane

A. i.e. Sevoflurane

D i.e. Sevoflurance

A i.e. Sevoflurane 

Sevoflurane is the agent of choice for inhalational induction in pediatric patientQ. Desflurane isoflurane are not used for induction because theyr are more pungent & are associated with more coughing, breath holding & laryngospasm during an inhalational induction.

A i.e. Sevoflurane