Ch. 9 Cardiac Monitoring (Test 2) Flashcards
Pulmonary artery pressure (PAP) is an important measurement in the care of critically ill pts with sepsis, ARDS, pulmonary edema, MI
know
What is normal PvO2?
35 to 45 mm Hg
PvO2 reflect
tissue oxygenation
If PvO2 level drops after intiation of or increase of PEEP then what has occurred?
A decrease in tissue oxygenation has occurred, caused by a drop in QT b/c of PEEP. PEEP should be decreased to maintain an adequate PvO2
Normal systolic PAP is
Normal diastolic PAP
Normal mean PAP
15 to 30 mm Hg
5 to 15 mm Hg
10 to 20 mm Hg
What are some conditions that increase PAP (3)
(1) Pulmonary hypertension (resulting from hypercapnia, acidemia, or hypoxemia, for example)
(2) Mitral valve stenosis
(3) Left ventricular failure
What are some conditions that decrease PAP?
(1) Decreased pulmonary vascular resistance (pulmonary vasodilation); caused by improved oxygenation, for example
(2) Decreased blood volume
When the balloon at the distal end of the catheter is inflated, it wedges in a branch of the pulmonary artery, blocking blood flow from the right side of the heart. The transducer measures the back pressure through the pulmonary circulation, which is equal to pressure in the left atrium and to the……..
The is called the and is measuring what?
left ventricular end- diastolic pressure (LVEDP)
Pulmonary capillary wedge pressure (PCWP)
PCPW is a measurement of the pressure of which sid eof the heart?
left side
The ballon should not be inflanted any longer than __ to __ seconds because blood flow obstruction for any longer may cause what?
15 to 20 seconds
pulmonary infarction
What is the normal PCWP
5 to 10 mm Hg
PCWP greater than 18 mm Hg indicates what?
Cardiogenic pulmonary edema
PCWP is ___________ in patients with cardiogenic pulmonary edema and is _________ in patients with noncardiogenic pulmonary edema.
Elevated
normal
What can cause a “damped” waveform in a A-line
- Occlusion of the catheter tip by a clot
- Catheter tip resting against the wall of the vessel
- clot in the transducer
- air bubbles in the line
How to correct: Occlusion of the catheter tip by a clot
correct by aspirating the clot and flushing with heparinized saline.
How to correct: Catheter tip resting against the wall of the vessel
correct by repositioning
catheter while observing waveform.
How to correct: Clot in transducer or stopcock
correct by flushing system; if no improvement is seen in the waveform tracing, disconnect the transducer and change the stopcock.
How to correct:Air bubbles in the line
correct by disconnecting transducer and flushing out air bubbles.
How to correct:Improper calibration:
correct by recalibration of monitor and strain gauge.
How to correct: Improper transducer position
correct by ensuring the transducer is kept at the level of the patient’s heart. If the transducer is placed below the level of the heart, the pressure reading will read higher than the actual pressure. If the transducer is placed above the level of the heart, the pressure reading will read lower than the actual pressure.
No pressure reading; causes include: Improper scale selection: How to correct
correct by selecting appropriate scale.
How to correct: Transducer not open to catheter:
correct by checking system and making sure the transducer is open to the catheter.
Systemic vascular resistance (SVR) is a measurement of the resistance that the left ventricle must overcome to eject its volume of blood. This is know as _________
afterload
What is normal SVR
900 x 1400 dyne x seconds x cm-5
Factors that increase SVR? (3)
a. Vasoconstrictors (dopamine, epinephrine)
b. Hypovolemia
c. Hypocapnia
Factors that decrease SVR? (3)
a. Vasodilators (nitroprusside sodium, morphine,
nitroglycerin)
b. Hypercapnia
c. Septic shock (early stages)
Pulmonary vascular resistance (PVR) is a reflection of the afterload of the ______ ventricle
right
PVR formula
MPAP-PCWP/QT
Normal PVR
1.38 to 3.13 mm Hg/L/min or 110 to 250 dyne x seconds x cm -5
Factors that increase PVR (7)
a. Vasoconstrictors (dopamine, epinephrine)
b. Hypercapnia
c. Hypoxemia
d. Acidemia
e. Pulmonary embolism
f. Pneumothorax
g. Positive pressure ventilation
h. PEEP and CPAP
Factors that decrease PVR
a. Improved oxygenation (pulmonary vasodilator)
b. Alkalemia (hypocapnia)
c. Vasodilating agents (nitric oxide, sildenafil,
prostacyclin, nitroprusside)
In a healthy person, intrapulmonary shunting occurs. This results from blood flow through the bronchial, pleural, and thebesian veins. These veins return blood to the left atrium, thus bypassing the oxygenation process in the lungs. This is called
anatomic shunt
Normal intrapulmonary shunting is about ___ to ___ of cardiac out and is primary caused by anatomic shunting
2% to 5%
What are some conditions that increase physiologic shunting? (4)
- PNA
- Pneumothorax
- Pulmonary edema
- Atelectassis
Shunts less than 10% is considered
normal
shunts 10% to 20% are considered
abnormal but is usually no significance
shunts 20% to 30% may be considered
life threatening and require cardiopulmonary support
shunts more than 30% is
serious and life threatening conitioning that requires agrresive cardiopulmonary support
Central venous pressure (CVP) may be monitored with a pulmonary artery catheter that is inserted through the (3)
subclavian, jugular or brachial vein
CVP is a measurement of what side of the heart?
Right artial pressure, which reflects systemic venous return and right ventricular preload
The normal value for CVP is
2 to 6 mm Hg
What are some conditions that increase CVP? (6)
Hypervolemia
Pulmonary hypertension
Right ventricular failure
Pulmonary valve stenosis
Tricuspid valve stenosis
Pulmonary embolism
What are some conditions that decrease CVP? (4)
1) Hypovolemia
(2) Vasodilation (from decreased venous tone)
(3) Leaks or air bubbles in the pressure line
(4) Improper transducer placement (above the
level of the right atrium)
Sinus bradycardia
- rate <60 bpm
- regular rhythm
What causes bradycardia (4)
- stimulation of the vagus nerve (tracheal suctioning)
- hypothermia
- Increased ICP
- Well condition athletes
What is thetreatment for bradycardia
- IF accompanied by SOB, hypotension, or abnormal beats, Atropine is used
- a peacemaker may also be indicated
Sinus tachycardia
- rate 100 to 160 bpm
- regular rhythm
What cause tachycardia (3)
- hypoxemia
- increased sympathetic nervous system stimulatiom (fear, anxiety)
- mediaction
Treatment for tachycardia
- stop/ treat the underying cause
- administartion of digitalis or beta blockers
Sinus arrhythmia
- rate: 60 to 100
- irregular rhythm
- wave pattern: R to R cycles vary more than 0.16 seconds
Cause and treatment
none, normal in young adults, healthy individuals
Premature ventricular contraction (PVC)
- rate: 60 to 100 bpm (< 6 PVCs per minute is considered minor, and >6 PVCs per minute is considered major
- regular rhythm, except for PVC
- wave pattern: the shape of the QRS is abnormal and WIDER THAN 0.12 seconds
What causes PVCs
- ventricular irritablity caused by HYPOXIA
- acid- base disturbances
- electrolyte abnormalties
- CHF
- coronary artery disease
- myocardial inflammation
Treatment for PVCs
IV lidocaine
(if more than 6 PVCs per minute then procainamide or propranolol)
When every other beat is a PVC, the arrhythmia is termed bigeminy, which is considered a dangerous arrhythmia. (A PVC occurring every third beat is termed trigeminy.)
KNOW
Elevated or depressed ST segment means what?
Heart attack
Atrial fibrilation
Deadly
- Rate: artial rate >350 bpm
- irregular rhythm
- Wave pattern abnormalities: P waves cannot be distinguished and have an uneven baseline; PR interval is also indistinguishable.
Causes for A-fib (4)
- hypoxia
- arteriosclerotic heart disease
- mitral stenosis
- valvular heart disease
Treatment for A-fib (3)
- cardioversion
- propranolol
- digitalis
Atrial fibrillation is considered to be a major arrhythmia, whereby the atria fail to pump blood adequately to the ventricles, which results in a significant decrease in cardiac output (QT). It may also result in
pulmonary emboli.
Atrial flutter
- Rate: artial 200 to 400 bpm ; ventricular 60 to 150 bpm
- regular (uniform) rhythm
- wave pattern: Pwaves have characteristic SAWTOOTH OR PICKET FENCE pattern
Causes of atrial flutter (4)
- hypoxia
- arteriosclerotic heart disease
- myocardial infarction (MI),
- rheumatic heart disease
treatment for artial flutter (4)
- cardioversion
- carotid artery massage,
- procainamide
- digitalis
- tranquilizers
Ventricular tachycardia (lethal)
- rate: 140 to 200
- regular rhythm
- wave pattern: P waves and PR intervals are absent or hidden in the QRS complex; each QRS is wider than normal with a run of three or more PVCs.
causes of V-tachy (5)
- arteriosclerotic heart disease
- coronary artery disease
- myocardial ischemia
- mitral valve prolapse
- hypertensive heart disease.
If you cant palpate a pulse in v-tach then what must you do?
defibrillate
Treatment for V-tach
- lidocaine
- defibrillation
- CPR
- procainamide
- amiodarone (very powerful have to wait 5 mins before you give another dose)
Ventricular fibrilation (lethal)
- rate: cannot be determined
- rhythm cannot be determoned
- wave pattern cannot be determined
Causes of V-fib (5)
- coronary artery disease
- hypertensive
- heart disease
- acute MI
- digitalis overdose.
Treatment for V-fib
defibrillation, CPR. If this arrhythmia is not reversed, death soon results because there is essentially no blood being pumped out of the heart.
Asystole treatment
CPR
First degree heart block
a. Rate: 60 to 100 beats/min
b. Rhythm: regular
c. Wave pattern abnormalities: PR interval longer than 0.20 seconds
TX for First degree heart block (2)
- atropine
- isoproterenol
Second degree heart block
a. Rate: 60 to 100 beats/min
b. Rhythm: regular or irregular
c. Wave pattern abnormalities: the QRS complex is normal but may be preceded by two to four P waves.
Causes of second degree heart block
myocardial ischemia; may be a progression from first-degree block
Treatment for second degree heart block (3)
- isoproterenol
- atropine
- pacemaker
Third degree heart block
a. Rate: atrial rate, normal; ventricular rate, less than 40 beats/min.
b. Rhythm: atrial and ventricular rhythms are regular but are independent of each other.
c. Wave pattern abnormalities: PR interval cannot be determined; QRS complex may be normal or widened.
Cause of third degree heart block (2)
- myocardial ischemia
- AV node damage.
Treatment for third degree heart block
external pacemaker
What are the 3 most deadly arrhythmias
- Third-degree heart block
- A-fib
- V-fib
PEA’s
A condition in which there is dissociation between the electrical and mechanical activity of the heart. The ECG pattern that appears on the ECG monitor does not reflect the actual mechanical activity of the heart.
A Holter monitor is a portable, battery-powered recording device that records the patient’s ECG tracing while the patient conducts daily activities. The monitoring is generally done over 24 hours.
KNOW
Which statement about the P wave on an ECG is FALSE?
A. It represents atrial depolarization.
B. It is a positive wave on the graph.
C. Normal duration time is 0.06 to 0.10 seconds.
D. It represents ventricular repolarization.
It represents ventricular depolarization.
The P wave of the cardiac cycle is a positive wave that represents atrial depolarization, or atrial contraction. The normal duration of the P wave is 0.06 to 0.10 seconds.
Artifact found on an ECG may be caused by which of the following?
- Electrical interference at the bedside.
- Poor electrode contact with the skin.
- Excessive movement of the patient
1, 2, 3
Artifact shows a misrepresentation of the cardiac waveform on the cardiac monitor and may be caused by electrical interference, poor electrode contact with the skin, or excessive movement of the patient.
In which of the following cardiac arrhythmias is the QRS complex abnormally shaped as well as wider than normal?
A. Sinus tachycardia
B. Premature ventricular contractions (PVCs)
C. Atrial fibrillation
D. Premature atrial contractions (PACs)
Premature ventricular contractions (PVCs)
PVCs are the result of ventricular irritability caused by hypoxemia, acid-base disturbances, electrolyte abnormalities, CHF, myocardial inflammation, coronary artery disease, and an excessive dosage of digitalis. PVCs are characterized by abnormally shaped QRS complexes, which are wider than normal. Lidocaine, procainamide, or propranolol is administered to treat PVCs.
A weak pulse is detected distal to the arterial catheter in a patient. This is indicative of which of the following?
A. Infection
B. Hemorrhage
C. Thrombosis
D. Tachycardia
Thrombosis
One of the complications of arterial lines is a thrombosis distal to the puncture site. If thrombosis and embolization occur, a weak pulse would be palpated distal to the puncture a continuous flush of heparin through the system helps prevent clot formation.
Which of the following conditions results in a decreased central venous pressure (CVP) reading?
- Hypovolemia
- Vasoconstriction
- Air bubbles in the CVP line
1 and 3
CVP is the measurement of right atrial pressure. The normal value is 2 to 6 mm Hg. Decreased values are seen with leaks in the CVP measuring line and low blood volume (hypovolemia).
The respiratory therapist palpates no pulse on a patient, but the ECG monitor shows QRS complexes on the tracing. The therapist should:
A. Get immediate ABG studies.
B. Recommend cardioverting the patient.
C. Begin cardiac compressions.
D. Recommend administering Nipride.
Begin cardiac compressions.
A QRS pattern seen on the cardiac monitor when no pulse is present is referred to as pulseless electrical activity (PEA). The monitor is indicating an erroneous tracing. If no pulse is palpated, cardiac compressions must be initiated.
After a cardiac arrest, a 48-year-old female begins receiving mechanical ventilation. A pulmonary artery catheter is in place. The following data are obtained:
BP 94/52 mm Hg
Pulse 116/min
PCWP 10mmHg
PAP 40/22 mm Hg
QT 3.5 L/min
Based on these data, which of the following has increased?
A. Pulmonary vascular resistance
B. Left atrial pressure
C. Stroke volume
D. Systemic vascular resistance
Pulmonary vascular resistance
Normal systolic PAP is 20 to 30 mm Hg. The PAP in this question is elevated, indicating pressure in the pulmonary vasculature has increased. This indicates an increase in pulmonary vascular resistance caused, for instance, by pulmonary vasoconstriction or an embolus. The CVP is slightly elevated, normal 2-6 mm Hg, as blood backs up into the right atrium due to the resistance to blood flow through the pulmonary vessels. The left atrial pressure (PCWP) is normal in this question (5 to 10 mm Hg).
The following data are collected from a patient receiving mechanical ventilation:
8:00 pm
PAP 24/12 mm Hg
PVR 2.1 mm Hg/L/min
PCWP 6 mm Hg
11:00 pm
PAP 42/20 mm Hg
PVR 4.2 mm Hg/L/min
PCWP 7 mm Hg
On the basis of this information, these changes are most likely the result of which of the following?
A. Pulmonary embolus
B. Left ventricular failure
C. Aortic stenosis
D. Overhydration
Pulmonary embolus
The PAP and pulmonary vascular resistance have increased. This occurs as a result of pulmonary vasoconstriction or, in this case, a pulmonary embolism. The clot in the pulmonary vessels is blocking blood flow, resulting in an increased PAP. PCWP is normal. Therefore left ventricular function is normal.
The following data have been recorded for a patient receiving mechanical ventilation:
CVP 5 mm Hg
PAP 28/10 mm Hg
PCWP 22 mm Hg
QT 2.8 L/min
On the basis of these data, the patient most likely has:
A. Pulmonary hypertension
B. Left ventricular failure
C. Pulmonary embolism
D. Right ventricular failure
Left ventricular failure
PCWP is elevated, indicating left ventricular failure. PCWP is an indication of left atrial pressure, with normal being 5 to 10 mm Hg. This may lead to cardiogenic pulmonary edema and decreased cardiac output, which are seen in this question. Right heart function is normal, as indicated by normal values for both CVP and PAP.
The ECG paper is made up of very small squares, which represent
0.04 seconds horizontally and 0.5 mV vertically (voltage axis)
So that counting time is easier, there is a darkened line at every fifth small square; from one darkened line to the next is 0.20 seconds (0.04 seconds 3 5 squares).
know
P wave (positive wave) represents
atrial DEPOLARIZATION (contraction)
How long is the p wave?
0.06 to 0.10 seconds
Q wave ( negative wave)
follows the pwave and maybe absent in healthy people
R wave (postive wave) follows the Q wave
S wave (negative wave that follows the R wave)
know
QRS complex represents
VENTRICULAR DEPOLARIZATION contraction
- duration: 0.06 to 0.10 seconds
A widened QRS pattern is seen with right bundle-branch block and premature ventricular contractions (PVCs).
KNOW
T wave (postive wave) represents
ventricular REPOLARIZATION
Inverted (negative wave) T waves indicate the presence of
coronary artery disease
PR interval represents the time it takes for the impulse to travel from the
SA node through the AV node
When is the PR intereval measured?
from the beginning of the P wave to the beginning of the Q wave
How long is the PR interval
0.12 to 0.20 seconds
PR may be prolonged in what heart diseases?
first and second degree heart block
ST segment
a. Measured from the end of the S wave to the beginning of the T wave.
b. Measures the time that is required for ventricular repolarization to begin.
When the ST segment is elevated above the baseline or depressed below the baseline this is an indication of
cardiac ischemia
Cardiac ischemia results from a decreased amount of oxygenated blood delivered to the left ventricle because of narrowed coronary arteries. If the blood supply is not restored, ventricular muscle may die; this is called
infarction
ST segment elevation or depression is a sign of coronary artery disease.
know
Flow-Directed Pulmonary Artery Catheter is also called a
Swan-Ganz Catheter
The pulmonary artery catheter is a balloon-
tipped catheter made of polyvinyl chloride that is used to measure central venous pressure (CVP), pulmonary artery pressure (PAP), and pulmonary capillary wedge pressure (PCWP), sometimes referred to as pulmonary artery wedge pressure (PAWP).
know
The _________ channel lumen is used for the measurement of _______ and for obtaining mixed venous blood from the pulmonary artery
distal;
PAP
The ________ channel lumen is used for the measurement of _____ or right artial pressure and the injection of fluids to determine _____
proximal
CVP
QT
The normal range C(a 2 v)O2, or arteriovenous O2 content difference, is
4 to 6 mL/dL.
If PCWP is elevated above 18 then it is considered
cardiogenic pulmonary edema or CHF
If PCWP is elevated and stops at 18 then it is considered (ask about pg 152)
non-cardiogenic pulmonary edema or ARDS
Complications of pulmonary catheter insertion (7)
- Damage to tricuspid valve
- Damage to pulmonary valve
- Pulmonary infarction
- Pneumothorax
- Cardiac arrhythmias
- Air embolism
- Ruptured pulmonary artery
