So, all of the alarms we've talked about
are on the anesthetic
machines, and that's part of the standard
monitoring system in
an operating room. In addition to that,
every patient gets an electrocardiogram.
And most of us use a 5 lead electrocardiogram,
because this is a much more sensitive way
of measuring for coronary ischemia,
lack of oxygen supply to the heart, than just
a 3 lead. We all use automatic,
and hopefully properly calibrated, blood
pressure cuffs. There's automatically,
on every patient, an oxygen saturation
monitor, an oximeter. The introduction of the oximeter
in the late 1980's, revolutionized
the way we treat patients
and improved care exponentially.
On the machine, there is end-tidal carbon dioxide
monitoring, so that we always know
that we're connected to the patient, and that the patient
is producing carbon dioxide, and it also allows
us to adjust ventilation, to make sure the carbon dioxide
level is within what we considered to be a safe
and normal range. We constantly monitor tidal volume
and airway pressure through the machine as well,
it's all done on every anesthetic
machine virtually seamlessly.
Then, at the discretion of the anesthesiologist,
there are additional monitors that can be put
in place. The peripheral nerve stimulator can monitor
muscle relaxant status, and we can actually
determine when it's possible to reverse
a muscle relaxant, by using this device.
Or we can determine that maybe the surgeon's right,
that the patient isn't adequately paralyzed,
and it's time to give more muscle relaxant.
Temperature monitoring is mandatory
in the United States, but is immediately
available in most places.
Initially it was introduced as a way
to monitor for malignant hyperthermia,
which we will talk about in more detail in a later lecture,
but it turns out that temperature changes are a late indicator
of that disorder. So, monitoring temperature
for that disorder is probably
not an important feature of temperature monitoring,
but operating rooms tend to be cold,
and people lose heat in operating rooms. And there's
danger in losing heat and becoming hypothermic.
So most of us measure temperature on a regular
basis as well. Modern anesthetic machines
also tell us exactly how much vapour
the patient is receiving on inspiration,
and more importantly, from the perspective of knowing
how deeper anesthetic is, shows us what their end-tidal
vapour level is. So their expired
vapour at the end of a breath. We know
exactly how much is returning to the machine,
and whether the patient is retaining enough to maintain
anesthesia. We also can use
across the thoracic wall, or transabdominally
to look for evolving
problems in the chest or in the abdomen.
There are a number of invasive monitors that are used