Sevoflurane

1
Sevoflurane
2
Sevoflurane
F3C
C
H
OCH2F
F3C
fluoromethyl 2,2,2-trifluoro-1-(trifluoromethyl)
ethyl ether
3
Some boring (but important data)

• Vapor pressure 157 (at 20?)
• Hal 243 Iso 240
• Solubility Blood/Gas 0.68 (Dog)
• Hal 2.36 Iso 1.4
• MAC 2.36 Maintain anesthesia at 1.3-1.5 times
  the MAC (MAC multiples)
• Hal 0.9 Iso 1.3

4
Sevoflurane

• Nonflammable, nonexplosive
• contains no chemical stabilizers
• nonpungent
• store at room temperature

5
Premedication

• No specific premedication is either indicated or
  contraindicated

6
Induction

• Mask induction usually 5-7 sevoflurane with
  oxygen is employed for masking in the dog.
• Anesthesia usually occur in 3 to 14 minutes.

7
Maintenance

• Surgical anesthesia is generally maintained with
  3.7-4 inhaled sevoflurane without premeds and
  3.3-3.6 with premeds.
• Different induction agents do not affect the
  required inhaled concentration.

8
Warnings

• Sevoflurane is a profound respiratory depressant.
• Because of the low solubility in blood,
  increasing the concentration may result in rapid
  hemodynamic changes compared to other volatile
  anesthetics.

9
Adverse reactions reported

• hypotension
• tachypnea
• muscle tenseness
• excitation
• apnea
• muscle fasciculations
• emesis

10
Precautions

• Will form CO if passed through dessicated (dry)
  soda lime.
• Bradycardia may occur (responds to atropine or
  glycopyrrolate)
• May increase the intensity and duration of
  nondepolarizing NMB. (It does in humans)
• Has not been evaluated in dogs used for breeding.

11
Precautions

• Has not been evaluated in puppies lt 12 weeks.
• NIOSH has recommended exposure limit of an 8 hour
  time-weighted average limit of 2 ppm for
  halogenated anesthetic agents in general.
• Direct exposure to eyes will cause mild
  irritation. (Wash with water for 15 min.)

12
Precautions

• Because of the low solubility, induction can
  occur quickly.
• Modest increases in cerebral blood flow.
• Little or no ability to potentiate seizures.
• Variable effect on heart rate.
• Dose dependent decreases in BP, CO, and
  myocardial contraction.

13
Compound A

• Sevoflurane reacts through direct contact with
  soda lime producing a substance known as compound
  A.
• The concentration increases with increasing
  sevoflurane concentrations and decreasing fresh
  gas flow rates. Increasing temperature also
  increases compound A.

14
Compound A

• Compound A is a dose dependent nephrotoxin in
  rats, the mechanism of toxicity is unknown.
• It does not appear to be a problem in dogs.

15
Drug interactions

• Has been safely in dogs receiving common
  veterinary products such as steroids, heartworm,
  and flea preventative products.
• Compatible with intravenous anesthetics,
  benzodiazepines, opioids, phenothiazines, and
  alpha2 agonists.