CHAPTER 12
CARDIOPULMONARY PROCEDURES
Content Outline
Introduction to Electrocardiography
1. Electrocardiograph:
instrument used to record the
electrical activity of the heart
2. Electrocardiogram (ECG):
graphic representation of the
electrical activity of the heart
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Purpose
a. Detect an abnormal cardiac rhythm (dysrhythmia)
b. Help diagnose damage to heart caused by MI
c. Assess the effect on the heart to cardiac drugs
d. Determine the presence of electrolyte
disturbances
e. Assess progress of rheumatic fever
f. Determine presence of hypertrophy of the heart
chambers
g. Use before surgery to assess cardiac risk during
surgery
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Introduction to Electrocardiography
• ECG cannot detect all cardiovascular
disorders
a. Cannot always detect impending heart
disease
• Used to assess cardiac functioning
a. Along with other diagnostic/laboratory tests
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Introduction to
Electrocardiography, cont.
• MA responsible for running ECG, which
includes:
a. Preparation of patient
b. Operation of electrocardiograph
c. Identification and elimination of artifacts
d. Labeling the completed ECG
e. Care and maintenance of
electrocardiograph
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Introduction to
Electrocardiography, cont.
• ECG machine formats:
a. Single-channel format: one lead recorded
at a time
b. Three-channel format: three leads
recorded at one time
•
Most offices use
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Three-Channel Electrocardiograph
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Structure of the Heart
1. Heart consists of four chambers
a. Upper chambers
•
Right atrium
•
Left atrium
b. Lower chambers
•
Right ventricle
•
Left ventricle
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Structure of the Heart
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Structure of the Heart, cont.
2. Pathway of blood
through the heart
a. Blood enters right
atrium: from superior
and inferior vena cava
•
Brought back to heart
after circulating in body
•
Deoxygenated: contains
very little oxygen and
high in carbon dioxide
(CO2)
b. Enters right ventricle
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Structure of the Heart, cont.
c. Pumped to the lungs
•
By way of pulmonary artery
– In lungs:
1) Picks up oxygen
2) Gives off CO2
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Structure of the Heart, cont.
d. Returns to the left atrium
of heart
•
By way of pulmonary veins
e. Enters left ventricle
•
Most powerful chamber of
the heart
–
Pumps blood to entire
body
f. Pumped into the aorta to
be distributed to the body
•
Nourishes tissues with
oxygen and nutrients
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Conduction System of the Heart
1. Sinoatrial node (SA node)
a. Located in upper portion
of right atrium
b. Consists of: knot of
modified myocardial cells
•
Able to send out an
electrical impulse
–
Without an external nerve
stimulus
c. Initiates and regulates
heartbeat
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Conduction System of the Heart,
cont.
2. Path of impulse from
SA node
a. Electrical impulse
discharged by SA
node
b. Impulse distributed
to right and left atria:
causes atria to
contract
•
Blood forced
through cuspid
valves and into
ventricles
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Conduction System of the Heart,
cont.
c. Impulse picked up by
atrioventricular (AV)
node
•
Knot of modified
myocardium
–
Located at base of
right atrium
d. AV node delays
impulse momentarily
•
Gives ventricles a
chance to fill with
blood
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Conduction System of the Heart,
cont.
e. Impulse transmitted
to bundle of His
•
Bundle of His is
divided into right
and left bundle
branches
f. Bundle branches:
relays impulse to the
Purkinje fibers
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Conduction System of the Heart,
cont.
g. Purkinje fibers:
distributes impulse
evenly to right and left
ventricles
•
Causes ventricles to
contract
–
Forces blood out of
ventricles
h. Entire heart relaxes
momentarily
i. New impulse initiated by
SA node
j. Cycle repeats
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Conduction System of the Heart
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Cardiac Cycle
1. Represents one complete heartbeat
2. Consists of:
a. Contraction of atria
b. Contraction of ventricles
c. Relaxation of entire heart
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ECG Cycle
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Waves
1. P wave
a. Represents electrical activity associated
with contraction of atria
b. Known as: atrial depolarization
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QRS Complex
2. Consists of Q, R, S waves
a. Represents electrical activity associated
with contraction of ventricles
b. Known as: ventricular depolarization
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T Wave
a. Represents electrical
recovery of the ventricles
•
Muscle cells are
recovering in preparation
for another impulse
b. Ventricular repolarization
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U Wave
a. Occasionally follows
T wave
b. Small wave
c. May be associated
with repolarization
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Baseline
1. Flat, horizontal line that separates
various waves
2. Waves deflect either upward or
downward from baseline:
a. Positive deflection: wave deflects upward
b. Negative deflection: wave deflects
downward
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Electrocardiograph Paper
1. Paper divided into two sets of squares
a. Small square: 1 mm high and 1 mm wide
b. Large square: 5 mm high and 5 mm wide
•
Each large square made up of 25 small squares
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Electrocardiograph Paper
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Electrocardiograph Paper, cont.
2. Physician uses graph to measures
waves, intervals, and segments
a. Determines if ECG is within normal limits
3. Paper consists of:
a. Black or blue base with white plastic
coating
b. Black or red graph printed on top of coating
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Electrocardiograph Paper, cont.
4. Heated stylus moves over heat-sensitive
paper
a. Melts away plastic coating
b. Results in recording of the ECG cycles
5. Paper is also pressure-sensitive
a. Handle carefully to avoid making
impressions
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Standardization of the
Electrocardiograph
1. Electrocardiograph must be standardized for
every recording
a. Quality control measure
•
Ensures an accurate and reliable recording
2. Normal standardization mark:
a. Height: 10 mm (10 small squares)
b. Width: approximately 2 mm wide (2 small
squares)
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Normal Standardization
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Standardization of the
Electrocardiograph, cont.
3. Three-channel machine: automatically
records standardization marks on
recording
4. If standardization mark is more or less
than 10 mm high:
a. Machine must be adjusted
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Electrocardiograph Leads
1. Consists of 12 leads
2. Each lead
a. Provides an electrical "photograph" of
heart's activity from a different angle
b. Results in 12 "photographs" of the heart
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Electrodes
a. Made of a
substance that is
a good conductor
of electricity
b. Picks up
electrical
impulses given
off by the heart
•
Conducts
impulse into
machine by lead
wires
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Electrocardiograph Leads, cont.
4. Amplifier: device located in machine that
amplifies the electrical impulses
a. Electrical impulses given off by the heart are very
small
•
Must be made larger (amplified)
5. Galvanometer: changes amplified voltages
into mechanical motion
6. Stylus (heated):
a. Records heart tracing on ECG paper
•
By melting plastic coating on ECG paper
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Electrocardiograph Components
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Electrocardiograph Leads, cont.
7. Limb electrodes
a. Right arm (RA)
b. Left arm (LA)
c. Right leg (RL): ground
•
Not used for recording
•
Serves as an electrical reference point
d. Left leg (LL)
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Electrocardiograph Leads, cont.
8. Chest electrodes
a. Abbreviated V or C
b. Uses six chest electrodes
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Electrocardiograph Leads, cont.
9. Electrode used with three-channel
recording
a. Disposable
b. Consists of self-adhesive tab
c. Electrode applied to skin using adhesive
backing
•
Thrown away after use
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Bipolar Leads
1. Leads I, II, III
2. Each bipolar lead: uses
two limb electrodes to
record electrical activity
of heart
a. Lead I: records heart's
voltage between right arm
and left arm
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Bipolar Leads, cont.
b. Lead II: records heart's
voltage between right arm
and left leg
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Bipolar Leads, cont.
c. Lead III: records heart's
voltage between left arm
and left leg
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Bipolar Leads, cont.
3. Lead II: shows heart's rhythm more clearly
than other leads
a. Rhythm strip: longer recording (12 inches) of lead II
•
Often
requested by
physician
Courtesy the Burdick Corporation, Milton, Wisc.
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Augmented Leads
1. aVR (augmented
voltage—right arm)
a. Records heart's voltage
between:
•
Right arm electrode and
a central point between
left arm and left leg
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Augmented Leads, cont.
2. aVL (augmented
voltage—left arm)
a. Records heart's
voltage between:
•
Left arm electrode and
a central point between
right arm and left leg
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Augmented Leads, cont.
3. aVF (augmented
voltage: left leg or
foot)
a. Records heart's
voltage between:
•
Left leg electrode and
a central point
between right arm and
left arm
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Augmented Leads, cont.
4. Leads I, II, III, aVR, aVL, and aVF
a. Records voltage from side to side and from
top to bottom of heart
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Chest Leads
1. V1, V2, V3, V4, V5, and V6
a. Record heart's voltage from front to back of
heart
•
From a central point "inside" the heart to a
point on the chest wall
– Where each chest electrode is placed
2. Leads must be properly located: to
ensure an accurate and reliable
recording
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Chest Leads
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Electrocardiograph Capabilities
Three-Channel Recording Capability
1. Records electrical activity of three leads
simultaneously
a. (Single-channel: records only one lead at a
time)
2. Advantage
a. ECG can be run in less time
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Three-Channel Recording
Capability, cont.
3. Leads recorded simultaneously
a. I, II, III
b. aVR, aVL, aVF
c. V1, V2, V3
d. V4, V5, V6
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Three-Channel ECG
Courtesy the Burdick Corporation, Milton, Wisc.
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Patient Data
Must be entered into electrocardiograph
before running
a. Patient age
b. Sex
c. Height
d. Weight
e. Medications
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Artifacts
1. Occasionally artifacts appear in recording
a. Artifact: additional electrical activity picked up by
electrocardiograph (not caused by heart)
2. Artifacts must be identified and corrected by
the MA
3. Most common artifacts:
a. Muscle
b. Wandering baseline
c. Alternating current (AC)
4. If unable to correct artifacts, machine may be
broken (Contact service technician)
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Muscle Artifact
1. Characterized by: fuzzy, irregular
baseline
Courtesy the Burdick Corporation, Milton, Wisc.
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Muscle Artifact, cont.
2. Due to:
a. Involuntary muscle movement
b. Voluntary muscle movement
3. Caused by:
a. Apprehensive patient
b. Patient discomfort
c. Patient movement
d. Physical condition (ex: Parkinson’s disease)
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Wandering Baseline Artifact
Courtesy the Burdick Corporation, Milton, Wisc.
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Wandering Baseline Artifact, cont.
1. Caused by:
a. Loose electrodes
•
To correct:
– Make sure electrodes are attached firmly to
patient's skin
– If electrode pulls loose:
1) Reattach with tape
2) Replace with a new electrode
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Wandering Baseline Artifact, cont.
– Make sure clips are firmly attached to
electrodes
– Make sure patient cable is well-supported
on patient's abdomen or table
1) Do not allow cable to dangle
b. Body creams, oils, or lotions on skin at
electrode application site
•
To correct:
– Remove by rubbing with alcohol using
friction
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Alternating Current Artifact
Appearance of AC artifact:
a. Small straight spiked lines that are
consistent
Courtesy the Burdick Corporation, Milton, Wisc.
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Alternating Current Artifact
1. Due to electrical interference
2. Can leak out from power used by
electrical appliances in room
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Alternating Current Artifact, cont.
Caused by:
a. Lead wires not following body contour
b. Other electrical equipment in room
– Unplug nearby electrical equipment (lamps,
autoclave, electrically powered examining table)
c. Wiring in walls, ceiling, floors
– Move patient table away from walls
d. Improper grounding of the electrocardiograph
•
Machine is automatically grounded when plugged in (by
three-prong plug)
•
Make sure plug is securely in wall outlet
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Interrupted Baseline Artifact
Courtesy the Burdick Corporation, Milton, Wisc.
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Interrupted Baseline Artifact, cont.
1. Caused by:
a. Metal tip of lead wire becoming detached
from alligator clip
•
To correct:
– Reattach lead to alligator clip
b. Broken patient cable
•
To correct
– Replace patient cable
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Holter Monitor Electrocardiography
1. Portable monitoring system that records
cardiac activity of patient for 24 hours
2. Patient maintains daily activities while
being monitored
3. Noninvasive procedure used to
diagnose:
a. Cardiac rhythm abnormalities
b. Conduction abnormalities
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Holter Monitor Electrocardiography,
cont.
5. Specific uses:
a. Evaluate unexplained syncope
b. Discover intermittent cardiac dysrhythmias not
picked up on ECG
c. Assess effectiveness of antidysrhythmic
medications
d. Assess effectiveness of artificial pacemaker
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Holter Monitor Electrocardiography,
cont.
6. Holter monitor consists
of:
a. Electrodes placed on
patient's chest
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Holter Monitor Electrocardiography,
cont.
b. Portable recorder: continually monitors
heart's activity
•
Types:
– Magnetic tape recorder: uses a magnetic
tape to record heart's activity
– Computerized
digital recorder:
uses a compact
flash memory
card to record to
heart's activity
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Wearing the Holter Monitor
Recorder held in a case
worn on:
a. Belt, around patient's
waist
b. Hung over patient's
shoulder by strap
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MA responsibility
a. Preparing patient
b. Applying and removing monitor
c. Instructing patient for procedure
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Holter Monitor Patient Guidelines
a. Keep electrodes and monitor dry
•
Do not shower, bathe, or swim while wearing monitor
b. Do not touch or move the electrodes
•
Prevents occurrence of artifacts on recording
c. Do not handle monitor or take out of case
d. Depress event marker only momentarily when
symptom occurs
•
Overuse of marker: causes masking of ECG signals
e. Do not use an electric blanket while wearing
monitor
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Electrode Placement, cont.
Electrodes must be properly placed on
patient's chest
a. Ensures accurate recording
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Electrode Placement, cont.
Check monitor after hooking up patient:
a. Purpose: To make sure a clear signal is
being relayed from electrodes to recorder
If problem occurs:
a. Patient may not be hooked up properly
b. Malfunction of cable or lead may be present
c. Reconnect leads and reposition electrodes
and check again
•
If problem still exists: monitor may need to be
repaired
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Activity Diary
1. Patient uses to record all activities/emotional
states during monitoring period
a. Examples of activities to record:
•
Physical exercise
•
Walking up/down stairs
•
Smoking
•
Bowel movements
•
Meals (including alcohol and caffeinated beverages)
•
Sexual intercourse
•
Medications consumed
•
Sleep periods
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Activity Diary, cont.
b. Examples of emotional states to record
•
Stress
•
Anger
•
Excitement
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Activity Diary, cont.
2. Also record physical symptoms:
a. Dizziness
b. Fainting
c. Palpitations
d. Chest pain
e. Dyspnea
f. Nausea
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Activity Diary, cont.
3. Include in recording:
a. Time of occurrence
4. Purpose of diary:
a. Dysrhythmia on tape compared with
patient's diary
•
To correlate symptoms with cardiac activity
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Activity Diary
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Event Marker
1. Most monitors have an event marker
a. Used with diary for patient evaluation
2. Patient depresses marker (momentarily)
when experiencing a symptom
a. Electronic signal placed on magnetic tape
or flash memory card
3. Alerts technician to significant event on
recording
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Evaluating Results
1. Holter monitor removed at end of 24-hour
period
2. Recording is evaluated by:
a. Viewing and analyzing recording on a Holter
scanning screen
b. Computer analysis
3. Printouts of the recording can be obtained for
further study
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Cardiac Dysrhythmias
1. Normal ECG: consists of P wave, QRS
complex, and T wave
a. Repeats in a regular pattern
2. Normal sinus rhythm: ECG that is within normal
limits
a. Waves, intervals, segments, cardiac rate are WNL
3. Normal heart rate range: 60 to 100 beats per
minute (bpm)
4. Sinus bradycardia: Below 60 bpm
5. Sinus tachycardia: Above 100 bpm
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Cardiac Dysrhythmias, cont.
6. Cardiac abnormalities include:
a. Extra beats
b. Abnormal rhythm (dysrhythmia)
c. Abnormal heart rate
7. MA should be able to identify
dysrhythmias on ECG
a. Alert physician
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Pulmonary Function Tests
1. Purpose of PFT: To assess lung
functioning
2. Assists in detection of pulmonary
disease
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Pulmonary Function Tests, cont.
3. PFT tests include:
a. Spirometry
b. Lung volumes
c. Diffusion capacity
d. Arterial blood gas studies
e. Pulse oximetry
f. Cardiopulmonary exercise tests
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Spirometry
1. Noninvasive screening test often
performed in medical office
2. Spirometer: computerized electronic
instrument
a. Measures:
•
Amount of air that is expelled from the lungs
•
Rate at which air is expelled
b. Report printed out as a table and/or graph
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Spirometry, cont.
3. Considered a screening test
a. Abnormal results: require additional PFT
tests
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Spirometry, cont.
4. Indications for performing spirometry
a. Patients who exhibit symptoms of lung
dysfunction (e.g., dyspnea)
b. Patients at high risk for lung disease
•
Smoking
•
Exposure to environmental pollutants
– Coal dust
– Asbestos
– Exhaust fumes
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Spirometry, cont.
c. Patients with lung disease
•
Asthma
•
Chronic bronchitis
•
Emphysema
d. Patients who will undergo surgery:
•
To assess probable lung performance during an
operation
e. Evaluation of lung disability/impairment for
a compensation program (e.g., coal miner)
•
Provide a number of measurements to assess
lung function
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Spirometry Test Results
1. Spirometry: provides numerous measurements
to assess lung function
2. Forced Vital Capacity (FVC): Maximum
volume of air that can be expired when patient
exhales as forcefully and rapidly as possible for as
long as possible (measured in liters)
a. FVC breathing maneuver
•
Patient takes a deep breath until lungs are
completely full
•
Patient blows all air out of lungs into a mouthpiece
– As hard and fast as possible until no more air
can be expelled
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Spirometry Test Results, cont.
1. To be considered an adequate test:
•
Patient must forcibly blow out all air and continue
smooth, continuous exhaling for 6 seconds
2. Minimum of three acceptable efforts must be
obtained
•
Some patients have trouble performing breathing
maneuver due to:
– Physical impairment
– Poor motivation
– Do not understand instructions
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Spirometry Test Results, cont.
3. Forced Expiratory Volume after 1
Second (FEV1): Volume of air that is
forcefully exhaled during first second of the
FVC breathing maneuver
a. Automatically determined by the spirometer
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Spirometry Test Results, cont.
4. FEV1/FVC Ratio: Comparison of FEV1
with FVC
a. Patient with healthy lungs: 70% to 75% of
air exhaled (FVC) is exhaled in the first
second (FEV1) of breathing maneuver
•
Expressed as a percentage
•
Example: patient with healthy lungs may have
ratio of 85%
– Means that 85% of exhaled air was exhaled
during first second of breathing maneuver
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Spirometry Test Results, cont.
b. Patients with chronic obstructive
pulmonary disease (COPD): ratio falls below
70% to 75%
•
Patient unable to move exhaled air out of lungs
because of an obstruction to the airflow
– Examples: Inflammation; damaged lung
tissue
c. Categories of airflow obstruction
•
Mild obstruction: 61% to 69%
•
Moderate obstruction: 45% to 60%
•
Severe obstruction: Less than 45%
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Spirometry Test Results, cont.
5. Evaluating the Results
a. Demographic factors used to evaluate
results entered into the machine:
•
Age
•
Sex
•
Weight
•
Height
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Spirometry Test Results, cont.
b. Based on demographic factors: computer
calculates predicted values.
•
Predicted value: What the results should be for
a patient with healthy lungs
c. Once test run: physician compares
measured values with predicted values
•
Values are printed out on the spirometry report
•
Assists physician in detecting pulmonary
disease
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Predicted and Measured Values
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Patient Preparation
6. Patient Preparation
a. Do not eat heavy meal for 8 hours before test
•
Full stomach: interferes with performing breathing
maneuver
b. Stop smoking at least 8 hours before test
c. Do not take bronchodilators 4 hours before test
d. Do not engage in strenuous activity 4 hours
before test
e. Wear loose, nonrestrictive clothing: keeps chest
area free
•
Easier to perform breathing maneuver
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