1. HEMODYNAMIC MONITORING: The Fundamentals

2. Goal:
Provide the participant with the basic knowledge required to care for a patient with an arterial line, central venous pressure/right atrial pressure line, and/or a pulmonary artery catheter.

3. Objectives: Define hemodynamic monitoring.
State indications for hemodynamic monitoring.
Identify the correct reference point for leveling & zeroing the hemodynamic monitoring system.
Identify components of normal arterial, right atrial, pulmonary artery, & pulmonary artery wedge waveforms.
Identify factors that can affect the accuracy of the waveforms.
Describe common complications associated with hemodynamic monitoring.
Discuss the nursing care for patients with hemodynamic monitoring.

4. Hemodynamic Monitoring:
The use of a device or instrument to provide physiological measurements in order to more closely and accurately monitor a patient’s condition.
Usually involves the use of an invasive catheter inserted into a body cavity or organ system.

5. Hemodynamic Monitoring - Examples:
Intra-arterial pressure
Central venous pressure
Intra-cardiac pressures:
Right atrial pressure
Pulmonary artery pressure
Pulmonary artery wedge pressure

6. Indications: Intra-arterial: Intra-cardiac:
Continuous blood pressure monitoring
Blood sampling
Frequent arterial or venous sampling
Ability to quickly assess the effects of medical interventions
Medications or fluid
Intra-cardiac:
Continuous monitoring of both right & left heart fluid status
Cardiac output
Mixed venous blood sampling
Ability to quickly assess the effects of medical management
Medications or fluid

7. Common Components: Monitoring device: Transducer cable Transducer
Amplifier
Oscilloscope
Transducer cable
Transducer
Transducer holder
Flush system:
Pressure bag
Fluid:
Heparin vs. NS
Pressure tubing
Catheter
Carpenter’s level

8. Common System Components:

9. Accurate & Reliable Waveforms/Values:
Technical factors:
Patient positioning:
Supine
Head of bed: 0-45°
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 & MAL (technically ½ AP diameter)
Mark the chest with washable felt pen

10. Phlebostatic Axis:

11. Leveling:

12. Accurate & Reliable Waveforms/Values:
Technical factors:
Zeroing:
Negates the force exerted by the atmosphere (760 mmHg at sea level)
Pressure transducers can be affected by changes in temperature
“Drift” will occur from the zero baseline over time

13. Accurate & Reliable Waveforms/Values:
Technical factors:
Pressure tubing & transducer system
System free of air
Length of tubing; correct tubing
System connectors tight; stopcocks Luer-locked
Adequate fluid in flush system
Flush solution pressurized to 300 mmHg
Dynamic response testing
Square wave, fast flush or snap test

14. Dynamic Response Test:
Figure A – Expected square wave test
Figure B – Overdamped
Figure C – Underdamped

15. Accurate & Reliable Waveforms/Values:
Overdamped:
Sluggish, artificially rounded & blunted appearance
SBP erroneously low; DBP erroneously high
Causes: large air bubbles in system, too compliant of tubing, loose/open connections
Overdamped? Shock states, vasodilation, aortic stenosis, thrombus on catheter tip, catheter kinked or against vessel wall

16. Overdamped Waveform:

17. Accurate & Reliable Waveforms/Values:
Underdamped or ringing:
Overresponsive, exaggerated, artificially spiked waveform
SBP erroneously high; DBP erroneously low
Causes: small air bubbles, too long of tubing, defective transducer
Underdamped? Vasoconstriction, hypertension, atherosclerosis, aortic regurgitation, hyperdynamic states (fever)

18. Underdamped Waveform:

19. Intra-arterial Pressure Monitoring

20. Blood Pressure Monitoring:
Non-invasive blood pressure:
Dependent on blood flow
Invasive, intra-arterial monitoring:
Dependent on pressure changes
Typically more accurate than NIBP
Allows for convenient arterial blood sampling

21. Arterial Line Insertion Sites:
Radial:
Most common site
Good collateral circulation
Accessibility & ease of maintenance
Modified Allen’s test
Brachial
Femoral
Dorsalis Pedis

22. Arterial Waveform: Peak systolic pressure:
Generated by left ventricular contraction
Peak systole correlates with QRS on ECG rhythm strip
Normal: mmHg

23. Arterial Waveform:

24. Arterial Waveform: Dicrotic notch: Diastole:
Closure of the aortic valve
Marks the end of ventricular systole & the beginning of diastole
Diastole:
Lowest pressure in arterial system
Measured just before systolic upstroke
Normal: mmHg

25. Arterial Waveform:

26. Arterial Waveform: Catheter location:
The more distal the catheter is placed, in relation to the aorta, the higher the systolic pressure & the lower the diastolic pressure

28. Complications: Infection: Hematoma Hemorrhage Thrombosis/embolization
Localized
Systemic
Hematoma
Hemorrhage
Thrombosis/embolization
Ischemia
Nerve damage

29. Nursing Care: Assess arterial line flush system:
Adequate, appropriate fluid
Pressurized to 300 mmHg
No air bubbles
Connections tight
Infection control
Level & zero q shift & PRN
Continuously observe arterial waveform quality; over/underdampened
Correlation to NIBP
Site care
Assess circulation distal to insertion site

30. Central Venous Pressure & Right Atrial Pressure

31. Central Venous Pressure & Right Atrial Pressure:
Indications:
Assessment of intra-vascular volume status:
Preload: the volume or pressure generated at end-diastole
Assess right ventricular function:
Follow trends
Secure access; often only IV access available

32. Central Venous Pressure & Right Atrial Pressure:
Measured through a catheter tip placed within the right atrium (RAP) or just outside RA in the vena cava (CVP):
Single-lumen, double-lumen, triple-lumen catheters
Pulmonary artery catheter
Access Sites:
Subclavian
Internal jugular vein
Femoral vein

33. CVP/RAP Pressures: Normal values: Increased CVP/RAP: 2–6 mmHg
Hypervolemia
Hyperdynamic states (increased cardiac output)
Cardiac tamponade
Constrictive pericarditis
Pulmonary hypertension
Heart failure
Pulmonary embolus
Positive pressure ventilation

34. CVP/RAP Pressures: Normal values: Decreased CVP/RAP: 2–6 mmHg
Hypovolemia:
Dehydration
Hemorrhage
Decreased mean systolic pressure
Vasodilation (specifically, venodilation):
Sepsis
Vasodilators

35. CVP/RAP Waveform: Waveform Components: “a” wave:
Atrial contraction (atrial kick)
Within the PR interval
“x” descent: atrial diastole
“c” wave:
Rise in pressure w/ tricuspid valve closure
Near the end of the QRS
“v” wave:
Passive atrial filling during ventricular systole
Following the T wave, within the T-P interval
“y” descent: passive atrial emptying

36. CVP/RAP Waveform:

37. Abnormal Waveforms: Large “a” waves: Loss of “a” waves:
Loss of A-V synchrony (Cannon Waves)
Tricuspid valve stenosis
Loss of “a” waves:
Dysrhythmias resulting in loss of P wave
Giant “v” waves:
Tricuspid insufficiency
Right ventricular failure

38. Complications: Pneumothorax Infection: Bleeding/hemorrhage
Localized, endocarditis, systemic
Bleeding/hemorrhage
Dysrhythmias:
Premature ventricular contractions
Ventricular fibrillation
Heart block
Thrombus/embolus
Perforation of cardiac chamber

39. Nursing Care: Assess CVP/RAP line flush system:
Adequate, appropriate fluid
Pressurized to 300 mmHg
No air bubbles
Connections tight
Infection control
Level & zero q shift & PRN
Continuously observe CVP/RAP waveform quality; over/underdampened
Correlation to clinical picture
Site care
Assess for complications

40. Pulmonary Artery Pressure & Pulmonary Artery Wedge Pressure

41. Indications: Assess left & right heart function:
Preload:
Right heart: RAP
Left heart: pulmonary artery diastolic & pulmonary artery wedge pressures
Cardiac output: thermodilution
Afterload:
Right heart: Pulmonary vascular resistance (PVR)
Left heart: Systemic vascular resistance (SVR)
Contractility:
Stroke work index (SWI)
Assess response to therapeutic interventions
Atrial and ventricular pacing
Mixed venous blood gas
Continuous venous oxygen saturation

42. Clinical Indications:
Complicated MI
End-stage heart failure
Acute pulmonary edema
Pulmonary embolus
Acute respiratory distress syndrome
Shock
Acute renal failure
Complex fluid management
Cardiac surgery
High-risk surgical patients

43. PA Pressure Monitoring:
Pulmonary artery catheter:
Standard is a #7-French, multi-lumen, radiopaque catheter
Marked in 10-cm increments
Multiple ports & openings
1.5-cc balloon at distal end

44. Pulmonary Artery Catheter:

45. Anatomy of a PA Catheter:
Components:
Thermistor
Balloon inflation port w/ gate valve
Proximal injectate port
Typically has three infusion ports:
RA infusion port & lumen opening
RV infusion port & lumen opening
PA distal infusion port & lumen opening
Balloon

47. Insertion & Placement:

48. Insertion: Access: Method: Right internal jugular Left Subclavian vein
Femoral
Method:
Patient positioning
Percutaneous
Vessel dilator & introducer sheath

49. RA

50. RV

51. PA

52. PAWP

53. Insertion:

54. RA RV PA PAWP

55. PA Pressures: Pulmonary artery systolic (PAS):
Normal PAS: 15–30 mmHg
Pulmonary artery diastolic (PAD):
Normal PAD: 5–16 mmHg
Pulmonary arterial wedge pressure:
Normal PAWP: 5–12 mmHg
All pressures measured at end-expiration

56. PA Pressures: Increased PA pressures: Decreased PA pressures:
Pulmonary hypertension
Pulmonary disease
Mitral valve disease
Left ventricular failure
Pulmonary embolus
Decreased PA pressures:
Hypovolemia
Pulmonary artery vasodilation (meds, SIRS, sepsis)

57. PA Waveform:

58. PA Waveform Components:
1. PA systolic peak
2. Dicrotic notch:
Closure of PA valve
3. PA diastole
4. Anacrotic notch:
Opening of PA valve

59. Pulmonary Artery Wedge Pressure:
Also: PCWP or PAOP
Normal PAWP: 5–12 mmHg
Indirect measurement of mean left atrial pressure (LAP) which is an indirect measure of left ventricular end-diastolic pressure (LVEDP) or left ventricular preload
Normally, PAWP is 1–3 mmHg lower than PAD
Physiologically impossible for PAWP to be higher than the PAD

61. PA

62. PAWP

63. PAWP:

64. PAWP Balloon Inflation:

65. PAWP Waveform Components:
“a” wave:
Atrial contraction (atrial kick)
“x” descent:
Atrial diastole
“c” wave:
Closure of mitral valve
“v” wave:
Atrial filling
“y” descent:
Passive atrial emptying

66. PAWP Waveform Components:

67. Obtaining PAWP:
Continuous, close observation of the ECG and the PAP waveform during procedure
Inflate balloon:
Open gate valve after syringe attached
Slowly & gently inflate with only enough air to “wedge” the balloon (typically cc)
Wedge for no more than seconds or 2-3 respirations
If strong resistance is met – do not inflate
If no resistance is met or blood in lumen - STOP
Measure PAWP at end-expiration
“a” wave method – most accurate

68. Obtaining PCWP:

69. Respiratory Variation:
PAP
waveform in a spontaneously breathing patient

70. Respiratory Variation:
PAWP waveform in a mechanically
ventilated patient

71. Monitoring Problems: Air bubbles in system Blood in system
Thrombus at tip of catheter
Spontaneous wedging & overwedging
Loss of pressure tracing
Pressures that do not match the clinical picture

72. Overwedging:

73. Complications: Infection Dysrhythmias Pneumothorax
Hematoma & hemorrhage
Valve rupture
Pulmonary artery rupture
Pulmonary infarct
Pulmonary embolus

74. Nursing Care: Goals of therapy Prevention of infection
Patient positioning
Assuring accuracy of data
Continuous waveform monitoring
Activity

75. Cardiac Output: Cardiac output:
Amount of blood pumped by the heart per minute
CO = SV x HR
Four physiologic factors affect CO:
Preload
Afterload
Contractility
Heart rate

76. Cardiac Output: Preload: Afterload:
Load (volume) that stretches the ventricles prior to contraction:
Right heart – CVP/RA
Left heart – PAD or PAWP
Afterload:
Impedance to the ejection of blood from ventricles:
Depends on: volume & mass of blood ejected; and compliance & size of vascular space into which blood is being ejected
Right heart – PVR
Left heart - SVR

77. Cardiac Output: Contractility: Heart rate
Ability of myocardial tissues to shorten and develop tension; “squeeze”:
Cannot directly measure clinically
Indirectly: LVSWI or RVSWI
Heart rate
Stroke volume: average volume of blood ejected per cardiac contraction

78. Cardiac Output: Thermodilution: Equipment:
Computer module/monitor w/ software
PA catheter w/ thermistor & injection set-up
5-10 cc fluid bolus (injectate)
Room temperature vs. iced injectate
Inject smoothly & quickly w/ end-expiration
Calibration factors: computation constant
Patient positioning

79. Cardiac Output: Normal values: Cardiac Output: 4–6 L/min
Cardiac Index: 2.5–4 L/min

80. References:
Boggs, R. L., & Woolridge-King, M. (Eds.). (1993). AACN procedure manual for critical care (3rd ed.). Philadelphia; Saunders.
Clochesy, J. M., Breu, C., Cardin, S., Whittaker, A. A., & Rudy, E. B. (1996). Critical care nursing (2nd ed.). Philadelphia; Saunders.
Marino, P. L. (1998). The ICU book (2nd ed.). Baltimore; Williams & Wilkins.