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Section Three:
Pulmonary Artery Pressure Monitoring
The pulmonary artery (PA), flow-directed,
balloon-tipped catheter has made possible the
assessment of right ventricular function,
pulmonary vascular status, and indirectly, left
ventricular (LV) function. Cardiac output (CO),
right atrial (RA), right ventricular (RV),
pulmonary artery (PA) pressures and the
pulmonary capillary wedge pressure (PCWP)
may be directly measured using a PA catheter.
The pressures and cardiac output obtained
using this catheter allow the clinician to calculate
derived parameters and facilitate diagnosis of
cardiovascular and cardiopulmonary
dysfunction, determine the therapy needed, and
evaluate the effectiveness of the interventions.
Pulmonary Artery Catheters
Several types of flow-directed, balloon-tipped
PA catheters are available in different sizes.
The type of catheter used is determined by the
parameters to be monitored and additional
requirements governed by the patient’s
condition. The 7.5-French (Fr. indicates
catheter lumen size), 110 cm long,
thermodilution catheter is the size used most
often.
Most PA catheters have several external ports
or lumen hubs corresponding to internal lumens
and lumen openings into the right heart and PA
(Fig. 6).
Four lumens with external hubs or ports are
common to all PA catheters:

proximal hub and lumen

distal hub and lumen

balloon inflation valve and lumen

thermistor connector and lumen.
The proximal or RA lumen opens into the
right atrium. It may be connected to a transducer
and used to obtain RA pressure measurements
and display of the RA pressure waveform
continuously or intermittently. Fluids or
medications may be administered through this
port. It is also used as the injectate port for
measuring cardiac outputs. Do not use to infuse
vasoactive agents such as dopamine or
nitroprusside if the injection method is used to
do intermittent cardiac outputs as patient will be
bolused with the vasoactive agent.
Figure 6. Pulmonary Artery Catheter
Section Three – Pulmonary Artery Pressure Monitoring
19
The distal or PA lumen hub is always
attached to a transducer and a continuous flush
system. Heparin is usually added to the flush
solution in order to prevent thrombi and fibrin
deposits on the catheter tip, although some
studies have shown it may not be necessary.
Check your unit protocol. The PA waveform is
displayed continuously, as are the PA systolic,
diastolic, and mean pressures. Mixed venous
blood gases, necessary for oxygen extraction,
oxygen consumption, and intrapulmonary shunt
measurements, may be withdrawn from the
distal PA port. The PA port is not usually used
for fluid or medication administration.
The balloon inflation port and lumen
enable the clinician to inflate the balloon at the
catheter tip with a small volume of air (1.5 ml
maximum) to measure the PA occlusion, or
pulmonary capillary wedge pressure (PCWP).
The tip of the PA catheter also contains a
thermistor. The external thermistor port is
connected to the bedside monitor or to a cardiac
output computer. The thermistor permits
measurement of the patient’s temperature in the
PA (core temperature), and it detects the blood
temperature change when solution is injected
through the RA port to obtain a cardiac output
measurement.
Specialty PA catheters include the above
components and additional features and lumens.
Some of the specialty features include:
 a second proximal lumen that serves as an
additional infusion port
 a right ventricular lumen that may be used for
infusions or insertion of a cardiac pacemaker
probe (designated for the particular type of PA
catheter) if temporary ventricular pacing is
required
 a lumen containing fiberoptic filaments
allowing continuous measurement of mixed
venous oxygen saturation (SvO2) or
continuous measurement and display of
cardiac output; and right ventricular ejection
fraction determinations.
Pulmonary Artery Catheter Insertion
Before the catheter is inserted consent for
the procedure should be obtained, the reason
for the procedure and the procedure itself should
be explained to the patient/family, and all
necessary equipment should be assembled.
The exact setup and equipment used will vary
depending on the institution. The tubing and
transducer are prepared as described in Section
One and the transducer is leveled and zeroed.
Prior to insertion each lumen of the PA catheter
is flushed with sterile solution from the flush
system to ensure all air bubbles are removed.
(Note: Fiberoptic SvO2 monitoring catheters are
calibrated prior to flushing lumens of the PA
catheter). The PCWP balloon should be inflated
with air to ensure proper inflation and in order to
evaluate for leaks before the catheter is
inserted.
Many institutions use insertion kits that
include a sterile sleeve that is placed over the
catheter prior to insertion. This allows catheter
manipulation, if necessary, after insertion,
without compromising sterile technique. Strict
sterile technique is required for the PA catheter
insertion procedure. The physician performing
the procedure wears a cap, mask, sterile gown,
and sterile gloves. The nurse assisting wears a
cap and mask and if manipulating the catheter,
sterile gloves. A sterile field is also used. The
PA catheter is inserted into a large vein through
an introducer catheter, which is usually placed
by a percutaneous approach. The most
common insertion site is the subclavian vein.
Other sites that may be used are the internal
jugular vein or femoral vein. Patient condition
and practitioner preference are major
determinants.
Once the introducer is in place, the PA distal
port is attached to the transducer/tubing and the
PA catheter is inserted by the physician and
threaded into place. Determination of the
catheter tip location is established by monitoring
the waveform and pressures on the bedside
monitor as the catheter passes through the vena
cava to the right atrium. The strip recorder is
started in order to ensure documentation of
Section Three – Pulmonary Artery Pressure Monitoring
20
waveform/pressure in each chamber. When the
catheter tip is in the right atrium, the PA balloon
is inflated with 1.5 mL of air to help “float” the
catheter through the tricuspid valve into the right
ventricle, across the pulmonic valve into the PA,
and eventually into the wedged position (Fig. 7).
The balloon is allowed to deflate passively after
the PA wedge waveform is noted on the monitor
and return of the PA waveform is confirmed.
The physician sutures the introducer in place.
 Determine the goals of therapy. It is important
for the RN to know the range of hemodynamic
parameters desired by the physician.
Nursing responsibilities during the insertion
procedure include:
Complications of PA Catheters
 Monitor sterile technique
 Monitor the changes in hemodynamic
waveforms
 Record the pressures in each chamber of the
heart after examining waveform strips
 Monitor the patient for complications.
Ventricular dysrhythmias are the most
common complication during PA catheter
insertion procedure.
 Complete documentation of insertion
waveform strips and pressures.
 Obtain cardiac output and hemodynamic
profile immediately after insertion in order to
document a complete baseline profile.
Pneumothorax
Pneumothorax is a complication of PA
catheter introducer insertion through the
subclavian vein. The anatomy of the patient can
make placement of a PA catheter difficult,
particularly if the patient is obese or has
torturous subclavian veins. The needle or
introducer sheath may puncture the lung during
insertion and cause an apical pneumothorax.
Less likely, but possible, is a pneumothorax
during insertion through the jugular vein. A
routine postinsertion chest radiograph should be
obtained and the patient should be evaluated for
signs and symptoms of a pneumothorax.
Infection
Figure 7. Normal cardiac waveforms and
pressures seen in heart chambers and PA.
After catheter insertion:
 Apply a sterile dressing over the insertion site.
 Verify catheter position with a chest
radiograph.
 Set monitor alarms appropriate for the patient.
Systemic infection and sepsis are caused by
contamination of the PA catheter, insertion site,
or pressure monitoring system. Careful
attention to sterile technique during pressure
tubing assembly, insertion, when entering the
system, and caring for the insertion site help to
prevent infection. Diagnosis of PA catheter
related sepsis is based on blood cultures, white
blood cell count, left shift on differential, and
fever in the absence of other sources of
infection. Clinical studies recommend that PA
catheters and catheter introducers should be
replaced at least every 5 days and the flush
solution, tubing, transducer every 72 hours (less
time than that recommended for arterial line
system changes. Dressing should be changed
according to unit protocol.
Ventricular Arrhythmias
Ventricular arrhythmias are common during
the insertion of a PA catheter, and may occur
during the removal of the catheter. As the
Section Three – Pulmonary Artery Pressure Monitoring
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catheter passes through the right ventricle, it
may irritate the endocardium and cause PVCs
and occasionally VT. The arrhythmias typically
resolve when the catheter is advanced into the
PA. After the PA catheter is in proper position in
the PA, it may become dislodged if not well
secured, and the tip may “fall back” into the right
ventricle. The patient may experience
arrhythmias, and the hemodynamic pressures
and waveform will reflect those of the right
ventricle. The catheter may be re-advanced by
the physician (or nurse, according to unit policy)
if protected by a sterile sheath, or may be
withdrawn back into RA. It is essential to have
ready access to emergency drugs and
equipment should the ventricular arrhythmias
persist.
take experience to detect!) This does not harm
the patient, but the balloon port should be
labeled as “balloon ruptured” in order to alert
subsequent caregivers and prevent injection of
air into the pulmonary artery. The PCWP will
not be able to be obtained if this happens.
Pulmonary Artery Rupture or
Perforation
A rare but very serious and potentially fatal
complication related to PA catheters is rupture
or perforation of the PA. Perforation of the PA
may occur during insertion or manipulation of
the PA catheter. Patients with friable PA may be
at some risk; proper advancement of the
catheter with the balloon fully inflated with 1.5
mL of air, however, and avoidance of advancing
the catheter too far into a small artery minimize
the chance of PA perforation. Rupture of the PA
is associated with overinflation of the balloon,
particularly if the catheter has migrated distally
into a small PA. Avoid overwedging of the
balloon port. (See Figure 7A) Close
observation of the PA waveform as the balloon
is inflated and only filling the balloon with the
amount of air to obtain a PCWP tracing prevent
overdistending a small PA. If less air is required
to obtain the PCWP waveform, the catheter has
migrated out of proper position. Do not inflate
the balloon longer than 10-15 seconds.
Balloon Rupture
The balloon may rupture. When this occurs,
the air injected does not passively return into the
syringe after being injected and/or it may “feel”
different when inflated, there is less resistance.
(Although this change in how it “feels” would
Figure 7A. Overwedge
Nursing Considerations
Nursing care of the patient undergoing PA
pressure monitoring is complex. The critical
care nurse must be able to interpret waveforms
and pressure data (discussed in more detail
below) and be alert to potential complications.
Interventions, outlined previously, that ensure
accurate readings and minimize operator error
apply to the patient with a PA catheter.
Consistency of leveling and measurement
techniques are especially important because
small variations in the zero reference point will
elicit large and erroneous changes in the RAP
and PCWP. Identification of technical problems
and the ability to troubleshoot possible causes
and intervene appropriately are crucial
competencies of the critical care nurse. Table 1
outlines possible problems and troubleshooting
strategies related to hemodynamic pressure
monitoring.
Review material from this section by
completing the Self-Test that follows, and then
compare your answers with those given.
Section Three – Pulmonary Artery Pressure Monitoring
22
Problem
Causes
Waveform overdamped
Waveform underdamped
Catheter fling, artifact
No waveform
Abnormally high pressures
Abnormally low pressures
Backflow of blood into
tubing

Air bubbles in system

Blood clots in system or tip of catheter

Catheter or tubing kinks

Loss of pressure in pressure bag

Catheter against vessel wall
Treatment/Interventions

Carefully examine system,
especially at stopcocks, for
bubbles and blood; flush out.

Withdraw blood back to
dislodge clots at catheter tip,
then flush system.

Inflate pressure bag to 300 mm
Hg

Notify physician; may need
catheter repositioned

Air bubbles, especially pinpoint


Tubing too long due to added
extentions.
Carefully check for tiny air
bubbles in system and flush.

Ensure tubing is 3 – 4 feet,
max.

Turn pt. to left side to assist
catheter in floating away from
pulmonic valve.

Stabilize tubing prior to
obtaining readings

Ensure tubing length is < 3-4 ft

Eliminate excess stopcocks

Ensure stopcocks are correctly
positioned.

Check for catheter/tubing kinks

Check that monitor channel is
on, cable connected and scale
is correct.

Catheter tip near pulmonic valve (PA
catheter)

Movement of tubing

Excessive tubing length or stopcocks

Stopcock turned

Catheter/tubing kinked

Monitor channel off, transducer cable
not connected to monitor, or scale set
inappropriately

Monitor not zeroed

Re-zero

Transducer below phlebostatic axis

Re-level

Monitor not zeroed

Re-zero

Transducer above phlebostatic axis

Re-level

Stopcocks turned the wrong way


Pressure bag not sufficiently inflated

Ensure that stopcock is turned
off to patient before opening
transducer to air.
Flush bag empty

Check position of all stopcocks.

Check pressure in bag, fluid
level.
Table 1. Troubleshooting technical problems of hemodynamic monitoring systems.
Section Three – Pulmonary Artery Pressure Monitoring
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Section Three – Pulmonary Artery Pressure Monitoring
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Section Three
Self-Test
Match the PA catheter port with its use:
1. _____ Connect cardiac output (CO)computer to this port.
a) Proximal port
2. _____ Inject CO injectate through this port.
b) Distal port
3. _____ Insert temporary pacemaker lead through this port.
c) Balloon port
4. _____ Obtain PCWP with use of this port.
d) Thermistor
5. _____ Attach this port to a transducer to obtain
e) Right ventricular
continuous PA readings
port
Match the technical problem with the possible cause:
6. _____Scale on monitor set inappropriately.
a) Blood backed up into tubing
7. _____ Stopcock or transducer turned the wrong way
b) Underdamped waveform
with dead-end cap off.
8. _____ Tubing too long.
c) Overdamped waveform
9. _____ Blood clot at catheter tip.
d) No waveform
10._____ Tubing movement outside patient or catheter moving
e) Catheter “fling”
inside patient.
Section Three – Pulmonary Artery Pressure Monitoring
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Section Three
Self-Test - Answers
Match the PA catheter port with its use:
1.
D
Connect cardiac output (CO)computer to this port.
a) Proximal port
2.
A
Inject CO injectate through this port.
b) Distal port
3.
E
Insert temporary pacemaker lead through this port.
c) Balloon port
4.
C
Obtain PCWP with use of this port.
d) Thermistor
5. B
Attach this port to a transducer to obtain continuous
readings.
e) Right ventricular PA
port
.
Match the technical problem with the possible cause:
6.
D Scale on monitor set inappropriately.
tubing
a) Blood backed up into
7.
A Stopcock turned the wrong way.
waveform
b) Underdamped
8.
B Tubing too long.
waveform
c) Overdamped
9.
C Blood clot at catheter tip.
d) No waveform
10. E Tubing movement outside patient or catheter moving
e) Catheter “fling”
inside patient
Section Three – Pulmonary Artery Pressure Monitoring
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Section Three – Pulmonary Artery Pressure Monitoring
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