EKG is a representation of the electrical events of the cardiac cycle.
Each event has distinctive wave form
The study waveform can lead to greatest insight into a patient’s
Myocardial ischemia and infarction
Electrolyte disturbances (i.e. hyperkalemia, hypokalemia)
Drug toxicity (i.e. digoxin and drugs which prolong the QT
Depolarization - Contraction of any muscle is associated with electrical
changes called depolarization. These changes can be detected by
electrodes attached to the surface of the body
Pacemakers of the Heart
o SA Node - Dominant pacemaker with an intrinsic rate of 60 - 100
o AV Node - Back-up pacemaker with an intrinsic rate of 40 - 60
o Ventricular cells - Back-up pacemaker with an intrinsic rate of 20
- 45 bpm.
o P wave - Atrial depolarization
o T wave - Ventricular repolarization
o QRS - Ventricular depolarization
The PR Interval - delay in AV junction - AV node/Bundle of His) delay
allows time for the atria to contract before the ventricles contract)
The ECG Paper
o Horizontally - One small box - 0.04 s
o One large box - 0.20 s
o Vertically- One large box - 0.5 mV
EKG Leads which measure the difference in electrical potential
between two points
1. Bipolar Leads: Two different points on the body
2. Unipolar Leads: One point on the body and a virtual reference point
with zero electrical potential, located in the center of the heart
o The standard EKG has 12 leads:
3 Standard Limb Leads
3 Augmented Limb Leads
6 Precordial Leads
Locating the V1/C1 position (fourth intercostal space) is critically
important because it is the reference point for locating the placement
of the remaining V/C leads. To locate the V1/C1 position:
1. Place your finger at the notch in the top of the sternum.
2. Move your finger slowly downward about 1.5 inches (3.8
centimetres) until you feel a slight
horizontal ridge or elevation. This is the Angle of Louis where the
manubrium joins the body of the sternum.
3. Locate the second intercostal space on the patient’s right side,
lateral to and just below the Angle of Louis.
4. Move your finger down two more intercostal spaces to the
fourth intercostal space, which is the V1/C1 position.
5. Continue locating other positions from V1.
Other important considerations:
o When placing electrodes on female patients, always place leads
V3-V6 and C3-C6 under the breast rather than on the breast.
o Never use the nipples as reference points for locating the
electrodes for men or women patients, because nipple locations
may vary widely.
Electrolytes are electrically charged minerals that help move nutrients
into and wastes out of the body’s cells, maintain a healthy water
balance and help stabilize the body’s acid level.
A blood test that measures the main electrolytes in the body—sodium,
potassium, chloride and bicarbonate (CO2)—can be used to evaluate
symptoms of heart disease and monitor the effectiveness of
treatments for high blood pressure, heart failure and liver and kidney
o The balance of sodium, potassium, chloride and bicarbonate in
the blood is a good indicator of how well the kidneys and heart
are functioning. Knowing which electrolytes are out of balance
can help your doctor determine a course of treatment.
o Sodium is regulated by the kidneys and adrenal glands. Low
sodium levels are caused by kidney disease and adrenal disease,
diuretics, diarrhea, and occasionally conditions that cause fluid
buildup in the body; the most common cause of high sodium is
dehydration. Normal sodium levels are 136 to 142 mmol/L.
o Potassium concentrations that are too high can be due to kidney
disease or drugs that can decrease potassium excretion from the
body. Low potassium can be a consequence of using certain
diuretics or of dehydration. Normal potassium levels are 3.5 to
o Chloride levels usually fluctuate with sodium levels. Low chloride
levels can occur with chronic lung disease, prolonged vomiting,
and with loss of acid from the body, called metabolic alkalosis.
High chloride levels may result from dehydration, but can also
occur with other problems that cause high blood sodium, such as
kidney disease. The normal range of chloride levels is 98 to 108
o The total CO2 test measures the total amount of carbon dioxide
in the blood, mostly in the form of bicarbonate, which is excreted
and reabsorbed by the kidneys. CO2 helps maintain the body’s
acid-base balance (pH) in concert with sodium, potassium and
chloride. Bicarbonate levels that are higher or lower than normal
may signify an acid/base or electrolyte imbalance, often due to
dehydration or drinking too much water. The normal range of
CO2 is 23 to 32 mmol/L.
CAPILLARY BLOOD GLUCOSE
Blood glucose monitoring is a way of testing the concentration of
glucose in the blood (glycaemia).
Diabetes mellitus type 2
Formerly non-insulin-dependent diabetes mellitus (NIDDM) or adultonset diabetes – is a metabolic disorder that is characterized by
high blood glucose in the context of insulin resistance and relative
Diabetes mellitus type 1
Is a form of diabetes mellitus that results from autoimmune
destruction of insulin-producing beta cells of the pancreas. The
subsequent lack of insulin leads to increased blood and urine
Normal blood glucose ranges
For the majority of healthy individuals, normal blood sugar levels
are as follows:
The normal blood glucose level in humans is about 4 mmol/L –
Shortly after eating the blood glucose level may rise temporarily
up to 7.8 mmol/L or a bit more in nondiabetics.
Is a condition in which an excessive amount of glucose circulates in
the blood plasma. This is generally a glucose level higher than 10
Is the medical term for a state produced by a lower than normal
level of blood glucose.
o Hypoglycaemia Symptoms
Weakness (especially noticeable as being "weak at the
CAPILLARY GLUCOSE MONITORING INSTRUCTION
o Wash patient’s hands thoroughly before beginning your capillary
blood glucose check or used some cotton wall and tap water to
o Insert the test strip so that the collection field is pointing up and
away from the meter.
o Firmly place the lancet pen against the area to be tested and
depress the button.
o Wipe off the initial blood drop. Squeeze the area, starting away
from the puncture and moving inward to aid in obtaining blood
o Place drop onto testing strip or place end of testing strip into the
drop of blood (see your owner's manual for best option)
o Check for sample acceptance and allow time for the machine to
work. Apply firm pressure to puncture with an alcohol wipe,
gauze or a bandage while you wait.
o Record glucose level and follow guidelines pertaining to
necessary actions for low or high glucose levels
X-rays- describe radiation which is part of the spectrum which
includes visible light, gamma rays and cosmic radiation
Unlike visible light, radiation passes through stuff.
When you shine a beam of X-Ray at a person and put a film on the
other side of them a shadow is produced of the inside of their body.
The chest x-ray is the most commonly performed diagnostic x-ray
examination. A chest x-ray produces images of the heart, lungs,
airways, blood vessels and the bones of the spine and chest.
An x-ray (radiograph) is a noninvasive medical test that helps
physicians diagnose and treat medical conditions. Imaging with xrays involves exposing a part of the body to a small dose of ionizing
radiation to produce pictures of the inside of the body. X-rays are
the oldest and most frequently used form of medical imaging.
The chest x-ray is performed to evaluate the lungs, heart and chest
A chest x-ray is typically the first imaging test used to help diagnose
symptoms such as:
o shortness of breath.
o a bad or persistent cough.
o chest pain or injury.
Physicians use the examination to help diagnose or monitor
treatment for conditions such as:
o heart failure and other heart problems.
o lung cancer.
o line and tube placement.
o fluid or air collection around the lungs.
o other medical conditions.
A chest x-ray preparation.
o You may be asked to remove some or all of your clothes
and to wear a gown during the exam. You may also be
asked to remove jewelry, removable dental appliances, eye
glasses and any metal objects or clothing that might
interfere with the x-ray images.
o Women should always inform their physician and x-ray
technologist if there is any possibility that they are
pregnant. Many imaging tests are not performed during
pregnancy so as not to expose the fetus to radiation. If an
x-ray is necessary, precautions will be taken to minimize
radiation exposure to the baby.
o No radiation remains in a patient's body after an x-ray
o X-rays usually have no side effects in the typical diagnostic
range for this exam.
o X-ray equipment is relatively inexpensive and widely
available in emergency rooms, physician offices,
ambulatory care centers, nursing homes and other
locations, making it convenient for both patients and
o Because x-ray imaging is fast and easy, it is particularly
useful in emergency diagnosis and treatment.
o There is always a slight chance of cancer from excessive
exposure to radiation. However, the benefit of an accurate
diagnosis far outweighs the risk.
o The effective radiation dose for this procedure varies. See
the Safety page for more information about radiation dose.
o Women should always inform their physician or x-ray
technologist if there is any possibility that they are
pregnant. See the Safety page for more information about
pregnancy and x-rays.
A stool analysis is a series of tests done on a stool (feces) sample to
help diagnose certain conditions affecting the digestive tract.
These conditions can include infection (such as from parasites,
viruses, or bacteria), poor nutrient absorption, or cancer.
For a stool analysis, a stool sample is collected in a clean container
and then sent to the laboratory. Laboratory analysis includes
microscopic examination, chemical tests, and microbiologic tests.
The stool will be checked for color, consistency, amount, shape,
odor, and the presence of mucus.
The stool may be examined for hidden (occult) blood, fat, meat
fibers, bile, white blood cells and sugars called reducing substances.
The pH of the stool also may be measured. A stool culture is done to
find out if bacteria may be causing an infection.
Stool analysis is done to:
o Help identify diseases of the digestive tract, liver , and
pancreas . Certain enzymes (such as trypsin or elastase) may
be evaluated in the stool to help determine how well the
pancreas is functioning.
o Help find the cause of symptoms affecting the digestive tract,
including prolonged diarrhea, bloody diarrhea, an increased
amount of gas, nausea, vomiting, loss of appetite, bloating,
abdominal pain and cramping, and fever.
o Screen for colon cancer by checking for hidden (occult) blood.
o Look for parasites, such as pinworms or GiardiaGiardia.
o Look for the cause of an infection, such as bacteria, a fungus,
or a virus.
o Check for poor absorption of nutrients by the digestive tract
(malabsorption syndrome). For this test, all stool is collected
over a 72-hour period and then checked for fat (and
sometimes for meat fibers). This test is called a 72-hour stool
collection or quantitative fecal fat test.
Collect the samples as follows:
o Urinate before collecting the stool so that you do not get any
urine in the stool sample.
o Put on gloves before handling stool. Stool can contain germs
that spread infection. Wash hands after removing gloves.
o Pass stool (but no urine) into a dry container.
o Either solid or liquid stool can be collected.
o If you have diarrhea, a large plastic bag taped to the toilet
seat may make the collection process easier; the bag is then
placed in a plastic container.
o If you are constipated, you may be given a small enema.
o Do not collect the sample from the toilet bowl.
o Do not mix toilet paper, water, or soap with the sample.
o Place the lid on the container and label it with name, and the
date the stool was collected. Use one container for each day's
collection, and collect a sample only once a day unless your
doctor gives you other directions.
o Take the sealed container as soon as possible.
The hematocrit test is often used to check for anemia, usually along
with a hemoglobin test or as part of a complete blood count (CBC). The
test may be used to screen for, diagnose, or monitor a number of
conditions and diseases that affect the proportion of the blood made
up of red blood cells (RBCs). RBCs circulate in the blood and carry
oxygen throughout the body.
A hematocrit may be used to:
o Identify and evaluate the severity of anemia (low RBCs, low
hemoglobin, low hematocrit) or polycythemia (high RBCs, high
hemoglobin, high hematocrit)
o Monitor the response to treatment of anemia or polycythemia
and other disorders that affect RBC production or lifespan
o Help make decisions about blood transfusions or other
treatments if anemia is severe
o Evaluate dehydration
The hematocrit is routinely ordered as a part of the complete blood
count (CBC). It may also be ordered by itself or with a hemoglobin level
as part of a general health examination. These tests are often ordered
when a person has signs and symptoms of a condition affecting RBCs,
such as anemia and polycythemia.
o Some signs and symptoms of anemia include:
Weakness or fatigue
Lack of energy
Shortness of breath
o Some signs and symptoms of polycythemia include:
hematocrit may sometimes be ordered when someone has signs and
symptoms of serious dehydration, such as extreme thirst, dry mouth or
mucous membranes, and lack of sweating or urination.
This test may be performed several times or on a regular basis when
someone has been diagnosed with ongoing bleeding problems,
anemia, or polycythemia to determine the effectiveness of treatment.
It may also be ordered routinely for people undergoing treatment for
cancer that is known to affect the bone marrow.
What does the test result mean?
o Red blood cells (RBCs) typically make up roughly 37% to 49% of
the volume of blood.
o Since a hematocrit is often performed as part of a complete
blood count (CBC), results from other components, such as RBC
count, hemoglobin, reticulocyte count, and/or red blood cell
indices, are taken into consideration. Age, sex, and race are
other factors to be considered. In general, the hematocrit mirrors
the results of the RBC count and hemoglobin.
o A low hematocrit with low RBC count and low hemoglobin
indicates anemia. Some causes include:
Excessive loss of blood from, for example, severe trauma,
or chronic bleeding from sites such as the digestive tract
(e.g., ulcers, polyps, colon cancer), the bladder or uterus (in
women, heavy menstrual bleeding, for example)
Nutritional deficiencies such as iron, folate or B12
Damage to the bone marrow from, for example, a toxin,
radiation or chemotherapy, infection or drugs
Bone marrow disorders such as aplastic anemia,
myelodysplastic syndrome, or cancers such as leukemia,
lymphoma, multiple myeloma, or other cancers that spread
to the marrow
Kidney failure—severe and chronic kidney diseases lead to
decreased production of erythropoietin, a hormone
produced by the kidneys that stimulates RBC production by
the bone marrow.
Chronic inflammatory diseases or conditions
Decreased production of hemoglobin (e.g., thalassemia)
Excessive destruction of red blood cells, for example,
hemolytic anemia caused by autoimmunity or defects in the
red blood cell itself; the defects could be hemoglobinopathy
(e.g., sickle cell anemia), abnormalities in the RBC
membrane (e.g., hereditary spherocytosis) or RBC enzyme
(e.g., G6PD deficiency)
o A high hematocrit with a high RBC count and high hemoglobin
indicates polycythemia. Some causes of a high hematocrit
Dehydration—this is the most common cause of a high
hematocrit. As the volume of fluid in the blood drops, the
RBCs per volume of fluid artificially rises; with adequate
fluid intake, the hematocrit returns to normal.
Lung (pulmonary) disease—if someone is unable to breathe
in and absorb sufficient oxygen, the body tries to
compensate by producing more red blood cells.
Congenital heart disease—in some forms, there is an
abnormal connection between the two sides of the heart,
leading to reduced oxygen levels in the blood. The body
tries to compensate by producing more red blood cells.
Kidney tumor that produces excess erythropoietin
Living at high altitudes (a compensation for decreased
oxygen in the air)
Genetic causes (altered oxygen sensing, abnormality in
hemoglobin oxygen release)
Polycythemia vera—a rare disease in which the body
produces excess RBCs inappropriately