1. Pulmonary Artery Pressure Monitoring
On-Line Review
January 2009
Reference: Special Care Manual SP-P-6.2 – 6.7
Copyright 2008, SIUH, Staff Development on-line

2. Objectives At the end of the review the participant will be able to:
Describe pulmonary artery waveforms.
Discuss pulmonary artery pressures.
Identify nursing measures to increase accuracy of measurements.
Describe cardiac output determination by intermittant thermodilution technique.

3. Equipment Informed consent, “side-site” verification
7.5 FR pulmonary artery catheter (PAC)
8.5 FR introducer set with “side-port”
Central line insertion tray and central line dressing kit with biopatch
Flush solution, pressure bag, disposable pressure tubing with transducer
Transducer holder

4. Edward’s Life Science VIP Thermodilution Catheter
Thermistor port
Proximal Injectate
PA Distal
Balloon inflation
port
RA infusion port
The standard catheter is 7.5 FR and 110 cm long. Maximal balloon volume 1.5cc

5. Quality Control Issues for PA Catheters
“Zero” system at setup and minimally 1X shift
Do square flush wave test minimally 1X shift, after zeroing, obtaining blood samples, with tubing changes, or if waveform distorted.
Prime tubing and stopcocks by gravity.
Maintain continuous flush system.
Use standard (universal) precautions, aseptic technique
Measure all values at end-expiration:
*In the “valley” for a patient on a ventilator
*In the “peak” for a patient breathing spontaneously.

6. Referencing the “zeroing” stopcock to Phlebostatic Axis
The phlebostatic axis is the approximate level of the left atrium. It is located
midway between the anterior-posterior chest wall at the 4th intercostal space.
The patient need not be flat, but must be supine.

7. Waveforms identified by movement of the catheter through
the right side of the heart into the
pulmonary artery and capillary bed:
Right atrial (RA)
Right ventricular (RV)
Pulmonary artery pressure (PAP)
Pulmonary capillary wedge pressure
(PCWP) or
Pulmonary artery wedge pressure
(PAWP)

8. Right atrial pressure (RAP) is measured by the distal tip of the PAC
on insertion or by the proximal port post insertion. The waveform
has two primary characteristics: “a” wave and “v” wave.
Pulmonic valve
QRS P
Right Atrium
a = atrial systole
v = ventricular systole
Tricuspid valve
a wave follows “P” wave on ECG
v wave follows the QRS complex on ECG
RAP = mean (average) of a wave

9. Measurement of Right Atrial Pressure (RA) from Pulmonary Artery Catheter
Normal RAP = 2 – 6 mmHg
The “a” wave represents atrial contraction and estimates atrial filling at end-diastole.
Locate the “a” wave by alignment with the PR interval on EKG.
Measure the mean (average) of the height of the “a” wave and the bottom of the “a’ wave at end-expiration.
*In the “valley” for a patient on a ventilator
*In the “peak” for a patient breathing spontaneously

10. RA Waveform “c” wave = closure of the tricuspid valve
“x” decent = follows closure of the tricuspid valve,
“y” decent = follows closure of the pulmonic valve

11. Alterations in RA Pressure
Reflects filling volume of the right atrium
Low pressure consistent with hypovolemia:
Trauma, blood loss
Dehydration
Loss of fluid from drains
Vomiting, diarrhea
Burns
3rd spacing of fluid
Consistent with tachycardia, ↓ urine output, dry skin & mucous membranes

12. Clinical Situations Consistent with Elevations in RA Pressures
Tricuspid stenosis, regurgitation
RV ischemia or failure
Pulmonary hypertension
Pulmonic stenosis
Pulmonary embolism
Atrial ventricular dissociation with loss of synchrony
Atrial arrythmias, A-V conduction blocks)

13. on insertion or from the RV port (gray) post insertion.
Right ventricular pressure (RVP) is measured from the distal tip of PAC
on insertion or from the RV port (gray) post insertion.
RVP has a systolic and diastolic component.
QRS
Systolic
pressure
Diastolic
pressure
Right ventricle
Onset of systole follows QRS complex on ECG
End diastole occurs at the onset of systole.

14. RV Waveform
Systole
Diastole

15. Reflects filling volume of right ventricle
Alterations in RVP
Reflects filling volume of right ventricle
Normal RV = 25-30/0-5 mmHg
Low pressure consistent with low volume
Usually accompanies low RAP
Elevation associated with:
Hypervolemia
Pulmonary embolism
Outflow obstruction
RV infarct/failure
Pericarditis/tamponade
LV failure
Primary and secondary pulmonary hypertension (PHTN)
Pulmonic stenosis
COPD

16. Pulmonary artery pressure (PAP) is measured from the distal tip
of PAC on insertion and distal tip post insertion. It has a systolic
and diastolic component.
QRS
Pulmonic valve PA
systolic PA
diastolic
Dicrotic notch
Represents closure of the pulmonic valve
Systolic pressure follows QRS on ECG.
Diastole begins at the closure of the pulmonic valve and continues to next onset of systole.

17. Alterations in PAP
Represents filling volume in the pulmonary artery and resistance to flow within the pulmonary circuit
Normal PAP = 20-30/8-15 mmHg
Low pressure consistent with hypovolemia
Consistent with ↓ RAP and ↓ RVP
High pressure consistent with
PHTN
COPD
Acute respiratory distress syndrome (ARDS)
Pulmonary embolism (PE)
Mitral stenosis
Left ventricular heart failure

18. PAP Waveform

19. Pulmonary capillary wedge pressure (PCWP) or pulmonary artery wedge pressure (PAWP) is measured from the distal port of PAC with balloon inflated.
a = atrial systole
v = ventricular systole
The PCWP represents left atrial filling pressure reflected through the
pulmonary circuit. Normal value 8-14 mmHg.
PCWP = mean (average) of “a” wave

20. PCWP indirectly measures left atrial pressure
Catheter tip looks “through” the pulmonary circulation to “see”
the left atrial pressure.

21. Measurement of PCWP from Balloon Port
Inflate balloon with only as much air as needed to create a change in the waveform (no more than 1.5cc air).
Observe for change in waveform.
Locate the “a” wave on the PCWP waveform.
Use the QRS as a marker to detect the “a” waveform.
Measure the mean of the “a” wave to obtain the PCWP:
*In the “valley” for a patient on a ventilator
*In the “peak” for a patient breathing spontaneously.
PA diastolic (PAD) should correlate to the PCWP and be 0-5 mmHg greater. (PAD ≥ PCWP)
High levels of positive end expiration pressure (PEEP) will raise the PCWP. Correlate with MD.

22. Alterations of PCWP Low pressure consistent with hypovolemia
Elevations consistent with:
Mitral stenosis/regurgitation
Aortic stenosis/regurgitation
Acute LV ischemia/infarct
LV failure
Atrial ventricular dissociation with loss of synchrony
Both RA and PCWP elevated in cardiac tamponade, constrictive pericarditis, and hypervolemia

23. Once inserted balloon should remain DEFLATED and ONLY
reinflated for periodic measurement of PCWP. PAP waveform should be
displayed at all other times.
Distal tip measures PAP and PCWP
Proximal tip measures RA and is site
for CO measurement and fluid
administration RA
infusion
port
(white)
Distal tip
(Yellow)
Proximal tip
(Blue)
Right ventricular
port site for
fluid
administration
Right ventricular
Port (Gray)

24. Complications of PA Catheters
Air embolism
Infection
Atrial & ventricular arrhythmias
Hemoptysis ( caused by excessive expansion of the balloon in the wedge position)
Areas of infarction
Thrombus formation /PE
Local endothelial damage
Pulmonary rupture
Thrombophlebitis
Pneumothorax

25. Summary of Pulmonary Artery Pressure Waveforms
Normal 2-6 mmHg Normal 20-30/ Normal 20-30/ Normal 8-14 mmHg
mmHg mmHg

26. Cardiac Output by Intermittent Thermodilution Technique
1. Verify catheter placement by X-ray and appropriate PA waveform.
Verify that the correct data is programmed into the computer in the CO menu
* Make of catheter (Baxter)
* Size of catheter (7.5 Fr)
* Volume of injectate (10cc)
* Use of in-line syringe
* Co-factor on "Auto"
* Patient temp is displayed on screen (Tb)
* Injectate temp is displayed on screen (Ti)
(Generally, room temp solution is used. If values are in
question, use iced solution)
Verify patient position:
*Patient supine, HOB no > 20º (If value is doubtful, use flat position.)

27. Causes of Error in CO Determination
Erroneous catheter placement, data entry
Concomitant volume infusion through PA catheter (Venous infusion port, RV or side ports)
Equipment malfunction (monitor, cable, catheter)
Tricuspid or mitral valve dysfunction (stenosis or regurgitation – blood must have forward flow)
Fever
Shivering
Positive pressure ventilation, PEEP
Injection technique too long
(Should be smooth and no longer than 4 seconds)

29. Congratulations! This completes part one of the review.
Please return to the class page and click on the link to take the post-test.
Part two of the review will be
conducted “on-unit” with the hemodynamic monitoring simulator.
Contact your manager.