The Use and Abuse of Nitrous Oxide:
No Laughing Matter
Erica Helfer
LEAP Independent Study
Summer 2008
What do you know about
History of anesthetics
1846 – Ether first demonstrated as a surgical
anesthetic.
CH3CH2OCH2CH3
What does an anesthetic drug need to
be able to do?
•
•
•
•
Relieve pain (analgesia)
Induce memory loss (amnesia)
Relax muscles
Reduce consciousness (if necessary)
What makes a good anesthetic?
• Chemical stability
• Minimal irritation upon inhaling (if gaseous)
• Rapid and pleasant onset of anesthesia (time to
loss of consciousness)
• Speed and safety of emergence from anesthesia
• Rapid changes in depth of anesthesia
• Minimal metabolism
• Absence of toxic effects in normal doses,
especially cardiovascular and respiratory and
toxicity to the liver
• Wide margin of safety
Two types of modern anesthetics
• Intravenous (drugs used in anesthesia)
– Hypnotics (e.g. Etomidate)
– Opioids (e.g. Morphine)
– Other (e.g. Ketamine)
• Inhalational (true anesthetics)
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–
–
–
–
Desflurane
Enflurane
Halothane
Isoflurane
NITROUS OXIDE
Nitrous oxide as an anesthetic gas
N
N
O
Synthesis of nitrous oxide
Nitrous oxide is commonly prepared by heating
solid ammonium nitrate to make water vapor
and gaseous nitrous oxide.
(a) What type of reaction is this?
(b) Write the balanced chemical equation for this
reaction.
+
=
Nitrous oxide in medicine
Pros and cons of nitrous oxide as an anesthetic
• PROS: nonflammable, nonirritating, powerful analgesic agent,
rapid onset and recovery (due to low blood/gas solubility),
little or no toxicity, not metabolized, ease in regulation of the
depth of action
• CONS: N2O is not a strong enough anesthetic for the use in
large operations. It is uncomfortable for people who have
trouble breathing through their nose. It is also a greenhouse
gas with potential to cause global warming when released
into the environment (310 times the ability to trap heat in
atmosphere than CO2).
Nitrous oxide in medicine
Nitrous oxide in industry