to make sure you're in the right place. Once you think
the tube is in place, inflate the cuff and
listen for a leak around the cuff. The inflation should be
just enough to stop the leak. Look at the chest wall.
Is it moving? Look at your end-tidal CO2
monitor. Are you getting CO2 back? Look at
the tube. Are you getting condensation of water vapour
on the inside of the tube? You won't get that
if you're in the esophagus, because there's no water vapour
to come back from the stomach. So check for those
things. And then listen to the lungs, listen
bilaterally, listen well load into the axillary
area and make sure you've got air entry.
This is a picture of three vapourizers
that are commonly used in anesthesia.
They are all drug specific.
They'll only manage one drug. They're calibrated
for atmospheric pressure or whatever
the atmospheric pressure is in the area in which
you live. The temperature, they change their
delivery of vapour dependent upon the temperature in the room.
So if it's in the middle of the summer and very hot,
they adjust to that. They are, also adjust
to the flow that you set through them.
And each is calibrated annually, as I mentioned.
I know the one on the left is for Isoflurane.
And I know that because it's got a purple band on it,
which is the Isoflurane color. The one on the right
is Sevoflurane, and I know that because it's got
a yellow top, which is the Sevoflurane color.
And the one in the middle is for Desflurane
and blue is not a particular color for any vapour,
but I know that the device
on the lower left of the vapourizer
is the filling port for Desflurane vapourizer and it
doesn't exist on any other kind of vapourizer.
So, that's easy to work out. So, what vapour
are you going to use? So let's start
with Isoflurane. Set the inspired
level of Isoflurane at 1-2% and
then adjust according to the patient's hemodynamics.
All of these vapours enhance muscle relaxation.
Isoflurane itself is too pungent
for inhalation induction.
Common to get Tachycardia with Isoflurane,
but you get no myocardial depression, slow
onset of action, slow recovery.
Bit of a hangover. Desflurane is not
as potent as Isoflurane, so you have to set it
at a higher initial level. Set it at 5-7%,
and again, adjust to the patient's hemodynamics. It also
enhances muscle relaxation, as all the vapours do.
It also is too pungent for inhalation induction.
Tachycardia and hypertension occur
if concentration is raised quickly. If you don't do it quickly,
if you only raise it a little bit of the time, you don't
get Tachycardia and hypertension. There's no
myocardial depression. Again, it's the fastest
onset recovery of any of the vapours, but it requires
a heated vapourizer, which is a more expensive
device and requires more careful calibration.
And finally, Sevoflurane. Set the
inspired to 1-3%, and again, adjust to hemodynamics.
It also enhances muscle relaxation.
It's an excellent choice for inhalation induction
as its smell is mild, and we talked about that
in an earlier lecture. It produces little change
in heart rate. No myocardial depression. It has
an intermediate speed of onset and recovery,
fairly quick actually, but not as quick as Desflurane.
And it's been very popular in pediatric anesthesia
because of its property as an inhalation induction agent.