Pulmonary Artery Pressure
Measurement
Issued May 2004
1
Lecture Content
 Patient Positioning
 Identify Phelbostatic Axis
 Leveling
 Square Wave Test
 Obtain PA Reading
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Patient Positioning
Angels
45º
Supine
Head of bed: 0-60°
30º
0º
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Leveling
Eliminates effects of hydrostatic forces on the
observed hemodynamic pressures
Ensure air-fluid interface of the transducer is
leveled before zeroing and/or obtaining
pressure readings
Phlebostatic axis:
 Level of left atrium
 4th ICS & ½ AP diameter
 Mark the chest with washable felt pen
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Identify Phlebostatic Axis
Intersection of the 4th ICS and
½ the anterior-posterior diameter of the chest
McHale DL, Carlson KK.
AACN Procedure Manual for Critical Care 4th ed
WB Saunders: Philadelphia, Pa 2001 (479)
With permission from Elsevier
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Mark location chest wall
with washable felt pen
Used with permission of PACEP Collaborative
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Level Transducer System
Ensure
air-fluid
interface
of the
transducer
is level to
phelbostatic
axis.
Used with permission of PACEP Collaborative
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Level Transducer System
 Relevel the transducer with any
change in the patient’s position
Angels
30º
45º
 Referencing the system 1 cm
above the left atrium decreases
the pressure by 0.73 mm Hg
 Referencing the system 1 cm
below the left atrium increases
the pressure by 0.73 mm Hg
0º
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Square Wave Test
 Determines the ability of the
transducer to correctly reflect
pressures
 Perform at the beginning of
each shift
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Square Wave Test
Figure A:
Expected
square wave
test
Figure B:
Over
damped
Figure C:
Under
damped
Pulmonary Artery Pressure Measurement Alert
Reprinted from Darovic GO.
Hemodynamic Monitoring:
Invasive and Noninvasive Clinical
Application 2nd ed.
Philadelphia,Pa: WB Saunders
Co;1995;161-162
Used with permission from Elsevier
10
Under Damped System
 Over responsive,
exaggerated, artificially
spiked waveform
 SBP erroneously high;
DBP erroneously low
Reprinted from Darovic GO. Hemodynamic Monitoring:
Invasive and Noninvasive Clinical Application 2nd ed.
Philadelphia,Pa: WB Saunders Co;1995;161-162
Used with permission from Elsevier
Pulmonary Artery Pressure Measurement Alert
 Causes: small air
bubbles, too long of
tubing, defective
transducer
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Over Damped System
 Sluggish, artificially
rounded & blunted
appearance
 SBP erroneously low;
DBP erroneously high
 Causes: large air
bubbles in system,
compliant tubing,
loose/open connections,
low fluid level in flush bag
Pulmonary Artery Pressure Measurement Alert
Reprinted from Darovic GO. Hemodynamic Monitoring:
Invasive and Noninvasive Clinical Application 2nd ed.
Philadelphia,Pa: WB Saunders Co;1995;161-162
Used with permission from Elsevier
12
PAP Documentation
 Measure at end expiration
 Measure pressures from a graphic tracing
 Measure pulmonary capillary wedge
pressure at end-expiration using the mean
of the a wave
 a wave indicates atrial contraction and falls
within the P – QRS interval of the corresponding
ECG complex
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Respiratory Component
 Changes in intrathoracic pressure
during respiration change PAP
readings
 Record and trend pressure
readings at end expiration
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Used with permission of PACEP Collaborative
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Used with permission of PACEP Collaborative
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Used with permission of PACEP Collaborative
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Respiratory Variation
Spontaneous ventilation
Mechanical ventilation
Aherns TS, Taylor LK. Hemodynamic
Waveform Analysis. Philadelphia, Pa:
WB Saunders; 1992 27
Used with permission from Elsevier
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Used with permission of PACEP Collaborative
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Used with permission of PACEP Collaborative
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Used with permission of PACEP Collaborative
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Used with permission of PACEP Collaborative
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Need Further Assistance?
For more information or further
assistance, please contact a
clinical practice specialist with the
AACN Practice Resource Network.
Email:
practice@aacn.org
Phone:
(800) 394-5995, x217
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