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