00:06
Hello ladies and gentlemen. Today
we're going to continue our series
of lectures on Anesthesia, by talking
about the drugs used in anesthesiology. This
slide shows a summary of the agents
we're going to talk about.
00:24
These include gases, vapours,
induction drugs, muscle relaxants,
reversal agents, opioids,
anti-emetic drugs, sedative drugs,
and local anesthetic. So, a lot of material
to be covered. The only gas that's used
in anesthesia is nitrous oxide. And what we mean
by gas, as opposed to vapour, is that it's a gas
in gas form at normal room
temperature, so it's normally
in a gas form. And the only time it's ever
in a liquid form, is when it's under very high
pressure. Nitrous oxide
is a weak anesthetic and
it must always be supplemented with other
anesthetic drugs, except in those very rare situations,
where patients are in a dive chamber, and having
anesthetic in a dive chamber where
the atmospheric pressure can be increased,
and then nitrous oxide becomes a reasonable anesthetic.
01:24
Nitrous oxide is very insoluble
in fat, which means
that it has a rapid onset, and a rapid
offset of effect. It's an excellent
analgesic without having narcotic like
properties. It's often used
in labour analgesia, and in the emergency
room for minor procedures, but
it's disappearing as a mainstream anesthetic
agent in modern practice, partly because
it causes gas to form in the gut
and other areas of the body where
there's gas spaces, and this can lead
to problems with healing, and
in the case of the gut, can lead
to a leak of an anastomosis.
02:12
The low fat solubility causes the gas
to diffuse into these gas spaces
in the body, such as the middle ear and the gut.
And this is an issue that is of concern. So,
we're not using it as much as we used to.
More commonly, we use vapours. And vapours