Desflurane (suprane) 1992 general description , effects on organ system, specific physical properties, inhalational advantages and disadvantages. desflurane vaporizer (TEC6 PLUS Datex Ohmeda), D-vapor , electrical vaporizer Zenon (Xe) the Nobel gas , its anesthetic properties.

1. Volatile Anesthetics
Desflurane, Xenon
Mahmood Hasan Taha
HD/ Anesthesia
Zakho General H.
Aug/ 2022

2. Desflurane (Suprane) 1992

3. General Description:
• Very similar structure to that of Isoflurane.
(Substitution of a fluorine atom for Isoflurane's
chlorine atom).
• Vapor pressure at 20 ℃ = 681 mmHg at sea level.
• At high altitudes (e.g. Denver, Colorado 1.6 km) it
boils at room temperature.
• 1.4km? 565m ? 440m ?

4. • These features (high v.p & low boiling point)
necessitate using a special vaporizer.
• Low solubility in blood → very rapid induction
& emergence.

5. Tec6 plus® Datex Ohmeda
Desflurane vaporizer
with illustration of mechanism of action

7. • Wakeup time are approximately 5% less than
those observed following Isoflurane.
• The alveolar concentration approaches the
inspired concentration much more rapidly
than other volatile agents.

8. • Blood/Gas: 0.42
(Blood/Gas: 0.69 for Sevoflurane).
• ¼ as potent as the other volatile agents.
• 17 times more potent than N2O.
• MAC = 6

9. Effects on organ systems

10. Cardiovascular:
( similar to those of Isoflurane).
• ↓ SVR, ↓ B.P
• COP maintained or slightly depressed at 1 -2
MAC.
• HR ↑ moderately.
• CVP ↑ moderately.

11. • Rapid ↑ in Desflurane concentration →
transient or sometimes worrisome elevation
in HR, B.P & catecholamine level more than
that with Isoflurane. These events can be
attenuated by fentanyl, esmolol, clonidine.

12. Respiratory:
• ↓ Vt, ↑ RR
• ↑ in resting PaCO2
• Depresses the ventilatory response to ↑PaCO2 .
• Pungency & airway irritation during induction can
be manifested by salivation, breath holding,
coughing & laryngospasm.
• ↑ airway resistance may ↑ in children with
reactive airway susceptibility.
• These problems make Desflurane a poor choice
for inhalation induction.

13. Cerebral:
• ↑ CBF, ↑ CBV, ↑ICP
• ↓↓ CMRO2 → cerebral vasoconstriction.
• ↑ ICP can be ↓ by hyperventilation.
• EEG , like Isoflurane: 2 MAC → silent EEG.

14. Neuromuscular:
• Dose dependent reduction in the response to
train of four & tetanic peripheral nerve
stimulation.

15. Renal:
• Safe.
• ↓ RBF, ↓GFR, ↓ UOP.
• Inhalation of choice for chronic renal failure
like Isoflurane.

16. Hepatic:
• Nearly safe.
• Minimum metabolism.
• Hepatitis is minimum.
• Hepatic O2 delivery is generally maintained by
maintaining the hepatic blood flow unlike
halothane.

17. Contraindications:
• Sever hypovolemia.
• History of Malignant hyperthermia.
• I.C. hypertension.

18. Drug interaction:
• Non depolarizing NMBA effect is increased.
• Epinephrine safe up to 4.5 mcg/kg (similar to
Isoflurane).
• Delirium in some pediatric patients.

19. • Desflurane, much more than any other volatile
anesthetics, has been associated with the
production of CO.
• The strongly alkaline and desiccated CO2
absorbent: CO forming when the absorbent is
dry, regenerate the original anesthetic when
wet.

20. • The first case of the day, when machines have
not been used for some time, or when fresh
gas flow has been left on for a protracted
period of time, Monday morning ; So, the
absorbent should be changed routinely
despite lack of apparent color change.

21. • The CO2 absorbents CO production from
greatest to least:
KOH- containing absorbents are(Baralyme®)(4.6%) >
classic soda lime (2.6%) > new soda lime (0%) >
calcium hydroxide lime (AMSORB®) (0%).

22. AMSORB® SODASORB®

23. • Choice of volatile anesthetic also determine the
amount of CO produced, and at equi MAC
concentrations: Desflurane > Enflurane >
Isoflurane.
• Sevoflurane when exposed to dry absorbent
(especially KOH-containing), this leads to CO
production and a rapid increase in absorbent
temperature, that exceed 300°C and it can lead to
fires , generation of forming acid leading to sever

24. airway irritation, and a lower circuit concentration
of delivered Sevoflurane compared to that of
vaporizer dial concentration.

25. Xenon (Xe)

26. • Xenon is a "noble" gas that has long been
known to have anesthetic properties.
• Inert element that does not form chemical
bonds.
• Scavenged from the atmosphere through a
costly distillation process.
• Odorless, non explosive. Inert (probably
nontoxic with no metabolism).

27. • Naturally occurring gas with low potency
( MAC=70%).
• Blood/Gas = 0.115, giving it very fast onset
and emergence.
• Anesthetic effects seem to be mediated by
NMDA (N-methyl-D-aspartate) receptor
inhibition by competing with glycine at the
glycine binding site.

28. • Little effect on cardiovascular, hepatic, or
renal systems and has been found to be
protective against neuronal ischemia.
• Does not trigger malignant hyperthermia
• As a natural element, it has no effect upon the
ozone layer compared with another NMDA
antagonist, nitrous oxide.
• High cost and little availability have prevented
its widespread use.