Download Transcripts/4_15 1-2 (McNicholas)

Cardiovascular: 1:00-2:00
Scribe: Sheena Harper
Wednesday, April 15, 2009
Proof: Patricia Fulmer
Dr. McNicholas
Assessing Cardiac Function
Page 1 of 7
I. Assessing Cardiac Function [S1]: The only thing that is going to be on the test is what she’s presented in
class.
II. Practical Assessment of Cardiac Function [S2]
a. ECG- We’ve already introduced the ECG, so we wont’ be talking in detail about the ECG.
b. Pulse measurement
c. Blood pressure
d. Heart sounds
e. Venepuncture
III. The Electrocardiogram (ECG) [S3]
a. We already discussed the ECG.
b. It’s a noninvasive method to measure the electrical activity of the heart. The ECG doesn’t tell you anything at all
about the mechanical activity of the heart. IT tells you about the electrical activity of the heart.
c. The small waves that occur in the extracellular fluid that surrounds the cells can be transmitted to the surface of
the thorax, and it can be picked up as electrical measurements.
d. You only get a deflection from the isoelectric line when there’s electrical activity actually occurring. There’s a
difference in the depolarized versus the polarized area of the thorax.
e. The limb lead can be placed on the wrist or the shoulder-that’s electrically equivalent. It doesn’t matter where
you place that electrode.
f. In the normal ECG the P-wave is atrial depolarization-that’s the initiation of the cardiac cycle.
g. There’s a delay in the conduction system. The QRS complex represents ventricular depolarization.
h. There’s no waveform on the ECG that represents the atrial repolarization. It occurs, but the large amount of
electrical activity in the ventricles overcomes any activity that you’d measure in the smaller atrial tissue.
i. The T wave is ventricular depolarization.
j. There’s two cardiac cycles shown here.
IV. Placement of limb electrodes [S4]
a. The limb electrodes in combination form the leads. It’s the combination of different electrodes that form the lead
configuration.
b. There’s a fourth electrode placed on the right leg that represents the ground.
V. Ambulatory Electrocardiogram [S5]
a. There’s another way of measuring an ECG besides lying on a table attached to a large machine. Holters are the
size of this microphone receiver.
b. Holter Monitoring – can be worn for a day or longer (24 hours to 30 days). Used to detect dysrhythmias that
may not appear in routine ECG.
c. They don’t give as clear a picture, and they only give the lead two type ECG.
d. They tell you over a prolonged period if there’s an atrial or ventricular arrhythmia. These may not always be
occurring, so these are very useful in detecting arrhythmias that are transiently occurring every now and then,
and it tells you something about the electrophysiological pathology that you may have.
VI. Video [S6]
a. This was supposed to show ventricular bradycardia (slowing down), tachycardia (speeding up), and ventricular
fibrillation (a complete nonsense undulation of the ECG).
b. She will give us the link to this website so we can look at it ourselves because it wasn’t working.
VII. Four Types of AV -Block [S7]
a. This slide is just to show what types of blocks might occur in the conduction system.
b. DON’T’ WORRY ABOUT LEARNING THE DETAILS ON THIS SLIDE. TAKE HOME MESSAGE: You can tell
where the conduction blocks are occurring in the conduction system of the heart based on the ECG
information.
c. There are different types of AV blocks, so the waveform of conduction moving down from the atria to the
ventricle.
d. PARTIAL BLOCK
e. First-degree block: slowing of conduction through the AV node --longer PR interval. The longer that takes it
shows there’s a much greater slowing than normally.
f. Second-degree intermittent block:
g. Mobitz type I. Progressively longer PR interval until you no longer get a QRS interval following the P wave.
Cardiovascular: 1:00-2:00
Scribe: Sheena Harper
Wednesday, April 15, 2009
Proof: Patricia Fulmer
Dr. McNicholas
Assessing Cardiac Function
Page 2 of 7
h. When you look at an ECG you look to see if there’s a P wave preceding regularly every QRS complex. If you
saw a P wave with no QRS complex forming, that might tell you that you have Mobitz type I second degree
block.
i. Mobitz type II. PR interval normal but every so often you drop a QRS complex (ventricular depolarization
missing).
j. Don’t worry about the underlying reasons for this.
k. This illustrates the type of arrhythmias you might see. It’s an arrhythmia because you’ve no longer got a regular
pattern of the QRS complex. The R cycles are completely erratic.
l. COMPLETE BLOCK
m. Third degree block: This occurs when there’s damage to the AV-nodal tissue.
n. Just as a reminder there’s a slowing of the waveform as it goes down through the AV node of the conduction
pathway. The advantage of that slowing is that the atria needs to contract before the ventricles contract, but the
atrial contraction only contributes 20% of the blood into the ventricle. 80% moves into the ventricle passively.
o. With a third degree block you get regular P waves occurring because the SA node is doing it’s thing, the atrial
tissue is doing its job right, but there’s no conduction down.
p. You get regular P waves as shown in this slide, but the Purkinje system takes over – unreliable and slow. I
q. The pacing of the Purkinje system is very slow (about 20 beats/min).
r. The Purkinje system is a very diverse network of tissue, and so you can have the excitation focus formed in any
portion of that, and the fastest part of that is going to take over as the pacer, but it’s not a very efficient way of
pacing the heart and causing contraction of the myocardium. You get irregular QRS complexes. This is
because the depolarization that is occurring, instead of that rapid movement of the waveform out through the
entire myocardium through the Purkinje fibers, there’s a waveform occurring in the Purkinje fibers, and it takes a
longer time to reach the rest of the myocardium.
s. You get prolongation of the QRS complex, and you also get irregular T waves forming because of the irregular
depolarization and because of that refractory period.
t. TAKE HOME MESSAGE: DON’T’ WORRY ABOUT MEMORIZING EACH TYPE, BUT JUST KNOW THAT
YOU CAN TELL WHERE THE CONDUCTION BLOCK IS OCCURING WITHIN THE CONDUCTION SYSTEM
OF THE HEART BASED ON THE ECG RECORDING THAT YOU WOULD MAKE.
VIII. FIBRILLATION [S8]
a. This is an example of Atrial Fibrillation- Normally there’s atrial depolarization and regular P waves. In atrial
fibrillation there can be an ectopic foci where the eclectrical activity is in within the myocardium. That can pace
very quickly. You don’t get the nice P wave forming. You get an irregular F wave. This can be extremely fast,
and you can get heart rates of up to 400 beats/ minute if it reaches through to the ventricular myocardium.
b. Because of the refractoriness of the ventricular myocardium there’s some prevention of the overall pacing of the
ventricular myocardium.
c. The atria flutter away, and blood will pull in the atria. This can form a clot, and you can get damage occurring
because of that.
d. Normal Sinus Rhythm- This just illustrates normal sinus rhythm to illustrate that you should have a P wave
occurring before the QRS complex as opposed to these fluffy (not sure what she said here) waves.
IX. Pulse Measurement [S9]
a. There are many regions of your body that you can take a pulse from.
b. Radial pulse in wrist.
c. Brachial pulse close to your elbow.
d. Carotid pulse in your neck.
e. Popliteal pulse behind the knee.
f. Dorsialis pedis pulse
g. Tibialis posterior pulse.
X. Arteries for taking pulse and blood pressure [S10]
a. This shows portions of the arm where you would normally take a pulse for a patient.
b. Depending on how strong that pulse is you might want to take it in the carotid or in another region of the body.
c. The brachial artery is used for measuring blood pressure.
d. You palpate the tissue and feel for the pulse.
XI. PULSE RATE [S11]
a. Place the tips of digits 2 and 3 (index and middle fingers) over the surface where the artery is found
b. Feel the pulse and count beats per minute
c. Normal adult PR: 60-100 bpm (beats per minute)
Cardiovascular: 1:00-2:00
Wednesday, April 15, 2009
Dr. McNicholas
d. < 60 = Bradycardia
e. > 100 = Tachycardia
Assessing Cardiac Function
Scribe: Sheena Harper
Proof: Patricia Fulmer
Page 3 of 7
XII. Assessment of the pulse [S12]
a. If the pulse is irregular, assess for a pulse deficit
b. 0+ = nonpalpable pulse- you can’t feel the pulse at all.
c. +1 = weak thready pulse, difficult to palpate
d. +2 = diminished pulse, cannot be obliterated
e. +3 = easy to palpate, full pulse, cannot be obliterated
f. +4 = full bounding pulse-what you want to have if you have a healthy pulse
XIII. Pressure changes in the atria [S13]
a. You can detect pressure changes in the atria within the jugular vein.
b. The jugular vein is palpated in the neck.
XIV.
Venous pulse measured in the fingertip [S14]
a. You can also get a venous pulse measured in the fingertips.
b. If you’ve ever had to have a pulse aulcemeter (sp?) placed on your fingertip that also detects the pulse rate as
well as the oxygen content of the blood.
c. This is a diagram from a biopack, which is a system that’s used for students to measure physiological systems.
Anywhere you can feel a pulse you can detect a pulse rate recording.
XV. STETHOSCOPE [S15]
a. An instrument used for auscultation, or listening to sounds (heart sounds) produced by the body.
b. PARTS OF THE STETHOSCOPE
i. earpieces
ii. tubing- the way the sound waves move into your ears
iii. amplifying devices- placed on the skin
1. diaphragm – the larger portion of the recording device
a. end of the amplifying device that is large, with a flat edge
b. best for amplifying (auscultating) high-pitched sounds e.g., breath, bowel, and normal heart
sounds
c. should be held firmly against the patient's skin
2. bell- smaller bell-shaped portion
a. end of the amplifying device that is small, with a hollow, cuplike shape
b. best for auscultating soft, low-pitched sounds e.g., extra heart sounds and murmurs
c. should be held lightly against the patient's skin- don’t press too hard with the bell
XVI.
Heart sounds [S16]
a. Depending where around the thorax you place the stethoscope you can hear noise waves that are occurring in
different valves in the heart.
b. If you want to listen to the aortic semilunar valve, which is going out from the ventricle to the aorta, and providing
blood to the rest of the body, you would place the stethoscope on the left side of the body. For the pulmonary
you can place it on the right side.
c. You listen to the apex for the left side, and alternatively if you want to listen to the right side you listen over the
other side.
d. You don’t listen right over the valves. You listen a little bit distal to the valves.
XVII. Events in the Cardiac Cycle [S17]
a. The first heart sound is heard right after ventricular contraction and closure of the mitral valve. (I have no idea
what she said right here after she coughed.) [18:02- 18:18:04]
b. Second heart sound occurs as the blood is pumped out into the aortia.
c. The actual relationship to the valves is when you hear the sounds, but it isn’t the slapping together of the valves,
it’s the vibrations in the myocardium that you’re hearing as that sound wave. It’s not valves slapping together,
although it’s sometimes described as a slapping sound, that’s not the normal sound you should hear. It’s
actually the washing kind of vibration in the myocardium that you hear with those heart sounds.
XVIII.
Note the [S18]
a. Listen for:
Cardiovascular: 1:00-2:00
Wednesday, April 15, 2009
Dr. McNicholas
Assessing Cardiac Function
b. Quality of the sound: (crisp or muffled)
c. Intensity (loud or soft)
d. Rhythm (irregular or regular)
e. Presence of extra sounds (murmurs)
XIX.
Scribe: Sheena Harper
Proof: Patricia Fulmer
Page 4 of 7
First heart sound [S19]
a. Mitral valve closure (end of atrial systole) and closure of the right atrioventricular valve. This occurs at the end
of atrial systole, so remember the blood moves into the ventricles, the pressure in the ventricles increases.
b. Because of that unidirectional movement of blood through he valves where back pressure causes the valve to
close. As that valve closes you get that vibration of turbulence of the blood, and you hear the “lub” of that lubdub sound.
c. Tricuspid valve usually quiet
d. “lub” in lub-dup
e. Immediately precedes apical pulse where you would palate the pulse, and you listen to that at the apex with the
bell or the diaphragm. It’s large enough to be heard with either recording method.
f. Immediately precedes carotid wave pulse
g. Apex with bell or diaphragm
XX. Second heart sound [S20]
a. Closure of aortic and pulmonary valves at end of ventricular systole. This is a lesser sound. You are hearing
vibration of blood in the aorta and the pulmonary vein.
b. “dup” in lub-dup
c. Immediately follows apical impulse
d. Immediately follows carotid wave pulse
e. Can be heard in the Upper left sternal edge with diaphragm of the stethoscope.
XXI.
Third heart sound [S21]
a. Normal in young healthy children
b. Indicates Impaired LV function if heard in adults.
c. Raised end diastolic pressure
d. Low pitched at apex – bell
e. “gallop” or “triple” rhythm when tachycardic
f. WE WON’T BE TESTED ON WHAT THE SOUNDS ACUTALLY SOUND LIKE. THIS IS JUST TO GIVE YOU
AN IDEA WHAT YOU HEAR IN THE STETHESCOPE.
g.
XXII. Fourth heart sound [S22]
a. Accompanies and is due to atrial systole
b. Only heard in normal sinus rhythm
c. Loud in left atrial hypertrophy
d. Low pitched at apex – bell
e. Triple or gallop rhythm
f.
XXIII. Murmurs [S23]
a. Turbulent flow across valves- If a valve is noncompliant, and you allow some blood to move through, you hear
that murmur or soft sound in the background. There are various grades.
b. Leaking or narrowed valve
c. Timing
d. Intensity- various grades.
e. Grade 1 – very quiet
XXIV.
f. Grade 6 – audible without stethoscope (Serious.)
Heart Pictures [S24]
a. This is a normal heart. When you are listening to murmurs you can actually hear the washing of the blood going
through a valve that hasn’t closed properly.
b. The valve leaks, and you hear that as a sound using the stethoscope.
Cardiovascular: 1:00-2:00
Scribe: Sheena Harper
Wednesday, April 15, 2009
Proof: Patricia Fulmer
Dr. McNicholas
Assessing Cardiac Function
Page 5 of 7
c. You can also have leak going through a septal type defect where you have an actual hole between the right and
left sides of the heart.
XXV. Web Links [S25]
a. http://www.blaufuss.org/tutorial/index1.html- this one wasn’t working
b. http://depts.washington.edu/physdx/heart/demo.html- you can link into this website. You can hear heart sounds.
c. She played the normal heart sound, the S3 sound- you can hear the abnormal sound there.
d. A murmur- an aortic stenois where the valve doesn’t close properly.
e. Again, don’t need to know these sounds for the test. This just gives you an idea of what they sound like.
XXVI.
BLOOD PRESSURE [S26]
a. Remember the four stages of the cardiac cycle: atrial diastole, atrial systole, ventricular diastole, and ventricular
systole.
b. When referring to systole or diastole, you are referring to contraction or relaxation of the ventricle. Therefore
systole or diastole means ventricular systole or ventricular diastole
c. You can actually measure the blood pressure from the sounds the blood makes as it moves through the brachial
artery.
d. You place a cuff on the upper arm, and you inflate the cuff. The occludes the blood, and as you release the
pressure on the artery, the pressure in the artery exceeds the pressure in the cuff, and you start to hear a
sound.
e. There was a link to hearing the blood pressure being measured. She will send us the link.
f. You raise the pressure in the cuff to about 20 mmHg more than what you think the pressure should be. Then
you slowly deflate the cuff, and you listen for the sounds as the pressure from the blood in the artery overcomes
the pressure in the cuff, and blood starts flow. You hear that washing sound of the blood (systole), and then as
it disappears, that’s the diastolic recording.
g. Pressure when the heartbeat can be heard (Systolic = contraction pressure)
h. Pressure when the heartbeat disappears (Diastolic = relaxation pressure)
i. BP is expressed as systole/ diastole
j. Normal BP is 120/80. The person in the link she is going to send us is hypertensive, so that is not normal blood
pressure.
XXVII. Arteries for taking pulse and blood pressure [S27]
a. This reminds you the position of the brachial artery where you take the BP measurement.
XXVIII. Sphygmomanometer [S28]
a. There are a variety of recording devices that you can use.
b. There’s the old-fashioned mercury column sphygmomanometer.
c. There are also modern devices as shown here.
d. sphygmomanometer or blood pressure meter is a device used to measure blood pressure, comprising an
inflatable cuff to restrict blood flow, and a mercury or mechanical manometer to measure the pressure. It is
always used in conjunction with a means to determine at what pressure blood flow is just starting, and at what
pressure it is unimpeded. Manual sphygmomanometers are used in conjunction with a stethoscope. The word
comes from the Greek sphygmós (pulse), plus the scientific term manometer (pressure meter). A
sphygmomanometer consists of an inflatable cuff, a measuring unit (the mercury manometer, or aneroid gauge),
and inflation bulb and valve, for manual instruments.
e. Operation
f. The cuff is normally placed smoothly and snugly around the left arm, at roughly the same vertical height as the
heart while the subject is seated with the arm supported. It is essential that the correct size of cuff is selected for
the patient. Too small a cuff results in too high a pressure, whilst too large a cuff results in too low a pressure.
The cuff is inflated until the artery is completely occluded. Listening with a stethoscope to the brachial artery at
the elbow, the examiner slowly releases the pressure in the cuff. As the pressure in the cuffs falls, a
"whooshing" or pounding sound is heard (see Korotkoff sounds) when blood flow first starts again in the artery.
The pressure at which this sound began is noted and recorded as the systolic blood pressure. The cuff pressure
is further released until the sound can no longer be heard. This is recorded as the diastolic blood pressure.
g. Significance
h. By observing the mercury in the column while releasing the air pressure with a control valve, one can read the
values of the blood pressure in mm Hg. The peak pressure in the arteries during the cardiac cycle is the systolic
pressure, and the lowest pressure (at the resting phase of the cardiac cycle) is the diastolic pressure. A
stethoscope is used in the auscultatory method. Systolic pressure (first phase) is identified with the first of the
continuous Korotkoff sounds. Diastolic is identified at the moment the Korotkoff sounds disappear (fifth phase).
Cardiovascular: 1:00-2:00
Wednesday, April 15, 2009
Dr. McNicholas
Assessing Cardiac Function
Scribe: Sheena Harper
Proof: Patricia Fulmer
Page 6 of 7
i.
j.
k.
l.
Types
Conventional (mechanical) sphygmomanometer with aneroid manometer and stethoscope
There are three types of sphygmomanometers:
Digital with manual or automatic inflation. These are electronic, easy to operate and practical in noisy
environments. Many have not been validated for all patient groups, and can give very inaccurate
readings.[citation needed] They measure mean arterial pressure (MAP) and use algorithms to calculate systolic
and diastolic values. In this sense, they do not actually measure the blood pressure, but derive the readings.
Digital oscillometric monitors are also confronted with “special conditions” for which they are not designed to be
used: arteriosclerosis, arrhythmia, preeclampsia, pulsus alternans, and pulsus paradoxus.
m. Digital portable finger blood pressure monitors with automatic inflation. These are more portable and easy to
operate, though less accurate. They are the smallest blood pressure monitors.
n. Manual. Should be operated by a trained person. Mercury manometers are considered to be the "gold standard"
of measurement because their measurement is absolute and does not require re-calibration. For this reason
they are often required in clinical trials of pharmaceuticals and for clinical evaluations of determining blood
pressure for high risk patients including pregnant women. Aneroid, mechanical, types are in common use, but
should be calibrated against a mercury manometer. The unit of measurement of blood pressure is millimeters of
mercury (mmHg). Blood pressures are usually given as an even number.
o. Manual sphygmomanometers require a stethoscope for auscultation.
XXIX.
How to measure blood pressure using a sphygmomanometer [S29]
a. When you inflate the cuff it does sound like the heartbeat, so you have to be careful to inflate it about 20mmHg
more than what you suspect the systolic pressure to be.
b. In phase one you hear a tapping sound.
c. Phase 2 and Phase 3- The sound softens. Then you have to listen really intently and keep the stethoscope very
still because if there’s any movement at all, you will pick up sounds and it confuses where you hear the diastolic
measurement.
d. When you hear silence, that’s your diastolic pressure. You should be able to measure that within about
2mmHg.
XXX.
Using the Sphygmomanometer [S30]
a. You have to place the cuff properly so the pressure is evenly spread over the brachial artery.
b. There is a right and left side to the listening cup – with the ear tips in your ears, tap lightly to be sure the
stethoscope is in the proper position
XXXI. Video [S31]
a. This was supposed to be the video of the hypertensive individual, but it didn’t work.
XXXII. Pulmonary Artery Catheter and Pressure Monitoring System [S32]
a. You can also use the pulmonary artery to measure pressure within the pulmonary side of the system.
b. That’s using a catheter that’s indwelling within the pulmonary artery and into the heart.
XXXIII. Arterial Pressure Monitoring System [S33]
a. In patients that you need to constantly monitor BP, you can use an arterial catheter that measures the pressure.
b. They are typically about 10mmHg more than what you’d measure on the surface.
XXXIV. VENIPUNCTURE: [S34]
a. Sterile technique that permits insertion of a needle or a catheter into a vein in order to replace fluid and
electrolytes.
XXXV. INDICATION FOR VENIPUNCTURE [S35]
a. To maintain or replace body stores of water, electrolytes, vitamins, proteins, fats & calories in patients who
cannot maintain an adequate intake by mouth.
b. To restore volume of blood components- you can restore blood volume very quickly with an indwelling catheter
with IV fluids pushed.
c. To administer safe & effective, continuous or intermittent infusions of medications or IV fluids.
d. To monitor Central Venous pressure
e. To provide nutrition or salts while resting the gastro-intestinal tract.
f. To keep a vein open in emergency
g. To obtain blood samples for lab tests.
h. To administer a bolus preparation or IV push medications
i.
Cardiovascular: 1:00-2:00
Wednesday, April 15, 2009
Dr. McNicholas
Assessing Cardiac Function
Scribe: Sheena Harper
Proof: Patricia Fulmer
Page 7 of 7
XXXVI. Contra-indication [S36]
a. May not always be the best method.
b. If Oral medication can be given effectively venipuncture wouldn’t likely be the best method.
c. If Intramuscular medication can be given effectively & comfortably (for frequent injections an IV route may be
preferred) you wouldn’t need an indwelling catheter.
d. Patient’s sensitive or allergic to IV equipment or medication.
e. Coagulation disorder (unless IV’s needed to treat the condition) If the patient clots you wouldn’t be able to
effectively provide fluids.
f. Patient refuses IV treatment
g. If the catheter isn’t placed correctly in the skin, you can get leakage of the fluids under the skin and swelling
around the catheter.
XXXVII. Obtaining venous access in difficult situations [S37]
a. The vein should be palpated by the operator's index finger to determine the relative size of the vessel and the
direction in which it runs so you know in which direction to place the catheter.
b. A firm to hard non-compressible vein is indicative of thrombosis and not suitable for further efforts at venous
access
XXXVIII.
Selection of a Vein [S38]
a. Peripheral vein provide the quickest & easiest approach for the establishment of an IV access for administration
of solutions & medication
b. Place on non-dominant arm.
c. Thoroughly inspect patient’s extremities
d. Most distal site of arm or hand is generally used first so that subsequent IV access sites can be moved
progressively upwards
e. Many other practical details….If the person has an edematous arm, you may have trouble finding a vein.
XXXIX. Methods of Distending a Vein [S39]
a. Apply manual compression above the site where cannula is to be inserted.
b. Have the client periodically clench the fist.
c. Massage the area in the direction of venous flow.
d. Apply tourniquet 2-6 inches above planned insertion site (An alternative is to apply BP cuff )
e. Lightly tap the vein site.
f. Ask patient to dangle his/her hand below heart level for few minutes.
g. For an infant, place his head lower than his body.
End [33:08]