Download Basics of Medical Equipment Lecture 5 - O6U E

A chemical sensor is a device that transforms chemical
information, ranging from the concentration of a
specific sample component to total composition
analysis, into an analytically useful signal. The
chemical information, mentioned above, may
originate from a chemical reaction of the analyte or
from a physical property of the system investigated.
An arterial blood gas (ABG) is a test that measures the
oxygen tension (PaO2), Carbon dioxide tension
(PaCo2), acidity (pH), oxyhemoglobin saturation
(SaO2), and bicarbonate (HCO3) concentration in
arterial blood.
Electrosurgical units (diathermy machines) were first
introduced during the early twentieth century to
facilitate haemostasis and/or the cutting of tissue
during surgical procedures.
This is achieved by passing normal electrical current
via the diathermy machine and converting it into a
high frequency alternating current (HFAC). The HFAC
produces heat within body tissues to coagulate
bleeding vessels and cut through tissue. At this high
frequency of over 300,000 Hz, the nervous system and
muscles are not affected when the current passes
through the body.
There are two different types of electrosurgery: monopolar and
bipolar.
Monopolar electrosurgery is the emitance of the HFAC from the
diathermy via an active electrode through the patients body
tissues and returned back to the diathermy machine via a return
electrode or patient return pad. It works because radio frequency
energy is concentrated by the surgical instrument's small surface
area. The electrical circuit is completed by passing current
through the patient's body to a conductive pad that is connectd
to the radio frequency generator. Because the pad's surface area is
large relative to the instrument's tip, energy density across the
pad is reliably low enough that no tissue injury occurs at the pad
site. Electrical shocks and burns are possible, however, if the
circuit is interrupted or energy is concentrated in some way. This
can happen if the pad surface in contact is small, e.g. if the pad's
electrolytic gel is dry, if the pad becomes disconnected from the
radio frequency generator, or via a metal implant
Bipolar electrosurgery is the passage of the HFAC from
the diathermy machine using only the patient's tissue
grasped between a pair of bipolar forceps, to form a
complete electrical circuit within the patient. Bipolar
diathermy does not require a patient return pad as
both active and return electrodes are combined within
the forceps. Advantage of bipolar electrosurgery is that
it prevents the flow of current through other tissues of
the body and focuses only on the tissue in contact.
This is useful in microsurgery and in patients with
cardiac pacemaker.
•Kidney dialysis is a procedure that is a substitute for many of the
normal functions of the kidneys.
•Dialysis allows patients with kidney failure a chance to live
productive lives.
•There are two types of dialysis: hemodialysis and peritoneal
dialysis.
•There are two major blood chemical levels that are measured are
the "creatinine level" and the "blood urea nitrogen" (BUN) level.
As these two levels rise, they are indicators of the decreasing
ability of the kidneys to cleanse the body of waste products.
There are two main types of dialysis: "hemodialysis"
and "peritoneal dialysis." Hemodialysis uses a special
type of filter to remove excess waste products and
water from the blood. Peritoneal dialysis uses a fluid
that is placed into the patient's abdominal cavity
through a special plastic tube to remove excess waste
products and fluid from the body.
Treatments last from 2 ½ to 4 ½ hours. During this
time, the dialysis staff checks the patient's blood
pressure frequently and adjusts the dialysis machine to
ensure that the proper amount of fluid is being
removed from the patients body.
Cardiopulmonary bypass (CPB) is a technique that
temporarily
takes
over
the
function
of
the heart and lungs during surgery, maintaining the
circulation of blood and the oxygen content of the
body. The CPB pump itself is often referred to as
a heart–lung machine or "the pump", and does the
work of the heart and lungs during the operation.
The heart-lung machine consists of a chamber that receives
the blood from the body, which is normally the
responsibility of the heart’s right atrium. This blood is then
pumped by the machine through an oxygenator, a function
normally the responsibility of the right ventricle. The
oxygenator removes the CO2 and adds oxygen, which is
normally the work of the lungs. The pump then pumps this
newly oxygenated blood back to the body, which is
normally the work of the left heart. The heart-lung
machine is connected to the patient by a series of tubes
that the surgical team places. At the end of the operation,
the surgeon gradually allows the patient’s heart to resume
its normal function, and the heart-lung machine is
"weaned off".
A permanent pacemaker, a small device that is implanted
under the skin (most often in the shoulder area just under
the collarbone), sends electrical signals to start or regulate
a slow heartbeat. A permanent pacemaker may be used to
make the heart beat if the heart's natural pacemaker (the
SA node) is not functioning properly and has developed an
abnormally slow heart rate or rhythm, or if the electrical
pathways are blocked.
•Single-chamber pacing, either the right atrium (upper
chamber) or the right ventricle (lower chamber) is
paced. Only one pacing lead is used.
•Dual-chamber pacing, both the right atrium and right
ventricle are paced. This requires two pacing leads.
One lead is placed in the right atrium, and the other
lead is placed in the right ventricle. Advisa MRI and
Revo MRI are dual-chamber pacemakers.
An implantable cardioverter defibrillator (ICD) looks
very similar to a pacemaker, except that it is slightly
larger. It has a generator, one or more leads, and an
electrode for each lead. These components work very
much like a pacemaker. However, the ICD is designed
to deliver two levels of electrical energy: a low energy
shock that can convert a beating heart that is in an
abnormal rhythm back to a normal heartbeat, and a
high energy shock that is delivered only if the
arrhythmia is so severe that the heart is only quivering
instead of beating.
•A pulse generator which has a sealed lithium battery
and an electronic circuitry package. The pulse
generator produces the electrical signals that make the
heart beat. Most pulse generators also have the
capability to receive and respond to signals that are
sent by the heart itself.
•Electrodes, which are found on each lead.
One or more wires (also called leads). Leads are
insulated flexible wires that conduct electrical signals
to the heart from the pulse generator. The leads also
relay signals from the heart to the pulse generator. One
end of the lead is attached to the pulse generator and
the electrode end of the lead is positioned in the
atrium (the upper chamber of the heart) or in the right
ventricle (the lower chamber of the heart). In the case
of a biventricular pacemaker, leads are placed in both
ventricles.
It is medical equipment which is used to counteract
fibrillation of the heart muscle and restore normal
heartbeat by applying a brief electric shock. It can be
used to treat defibrillation and tachycardia.
:
1. ASYNCHRONIZED
Turn the power on the patient without electrocardiogram
2. SYNCHRONIZED CARDIOVERSION (Synchronize with
Cardiogram)
1: Place the paddles on the patient.
Place the left (STERNUM) paddle on the right side
of sternum and below the clavicle.
Place the right (APEX) paddle on the level of 5th
intercostal space and midaxillary line.
2: When the patient needs defibrillation, press the CHARGE
button on the APEX paddle or CHARGE/AED button on the
front panel to start
When defibrillation becomes unnecessary after charging is
completed
Turn the Energy/Mode Select Control to the DISARM or
OFF position.
The defibrillator internally discharges charged energy
3: Check the skin-paddle contact impedance.
4: Discharge the energy to the patient.
1. When charging or discharging, do not touch
anything other than the handles.
2. Do not move the defibrillator when any charged
energy remains in the defibrillator.
3. Before defibrillation, all persons must keep clear of
the bed and must not touch the patient or any
equipment