Hemodynamic monitoring is the process of measuring various blood pressure parameters in order to assess the status of a patient’s cardiovascular system. It can be used to guide the care a patient receives and to monitor their progress.
In this article, we will provide an overview of hemodynamic monitoring, including its current applications in respiratory care. We provided helpful practice questions on this topic as well.
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What is Hemodynamic Monitoring?
Hemodynamic monitoring is the process of measuring various parameters related to blood flow and pressure. Essentially, it allows medical professionals to measure the pressure inside a patient’s heart, veins, and arteries.
This information can be used to assess the function of the cardiovascular system and guide treatment decisions. In some cases, it can also be used to monitor a patient’s progress.
Types of Hemodynamic Monitoring
There are several different types of hemodynamic monitoring, each of which measures different parameters. Some examples include:
- Mean arterial pressure
- Central venous pressure
- Pulmonary artery pressure
- Pulmonary capillary wedge pressure
- Systemic vascular resistance
- Pulmonary vascular resistance
- Cardiac output
- Cardiac index
Each of these parameters provides important information about the status of the cardiovascular system.
Mean Arterial Pressure
Mean arterial pressure (MAP) is a measurement of the average blood pressure in the arteries. It is typically calculated using the following formula:
MAP = (Systolic Blood Pressure + (2 x Diastolic Blood Pressure)) / 3
MAP is considered a good overall measure of blood pressure because it takes into account both the systolic and diastolic blood pressures.
Central Venous Pressure
Central venous pressure (CVP) is a measurement of the pressure in the vena cava, which is the large vein that carries blood from the body to the heart.
CVP is important because it can give insight into a patient’s fluid volume status, which is a key factor in managing many types of illnesses.
It also helps gauge a patient’s cardiac function by measuring how well the right ventricle of the heart is able to pump blood.
Pulmonary Artery Pressure
Pulmonary artery pressure (PAP) is a measurement of the pressure in the pulmonary arteries, which are the arteries that carry blood from the heart to the lungs.
The PAP measurement provides important information about the function of a patient’s heart and lungs.
Pulmonary Capillary Wedge Pressure
Pulmonary capillary wedge pressure (PCWP) is a measurement of the pressure in the pulmonary capillaries, which are the small blood vessels that connect the pulmonary arteries and veins.
This measurement is used to assess the left ventricular filling pressure of the heart and to guide fluid management in patients with heart failure. It provides an indirect measurement of the left atrial pressure.
Systemic Vascular Resistance
Systemic vascular resistance (SVR) is a measurement of the resistance to blood flow in the systemic arteries. It can be calculated with the following formula:
SVR = (MAP – CVP) x (80 / Cardiac Output)
This measurement is important because it provides an indication of the heart’s ability to pump oxygenated blood to the organs and tissues of the body.
Pulmonary Vascular Resistance
Pulmonary vascular resistance (PVR) is a measurement of the resistance to blood flow in the pulmonary arteries. It can be calculated with the following formula:
PVR = (MPAP – PCWP) x (80 / Cardiac Output)
This measurement is important because it provides an indication of the right heart’s ability to pump oxygenated blood to the lungs.
Cardiac Output
Cardiac output (CO) is a measurement of the amount of blood that the heart pumps in one minute. CO is calculated by multiplying the heart rate (HR) by the stroke volume (SV).
CO = Heart Rate x Stroke Volume
HR is the number of times the heart beats per minute and SV is the amount of blood that is pumped out with each beat.
Cardiac Index
Cardiac Index (CI) is a hemodynamic parameter that measures the amount of cardiac output in relation to a patient’s size. It can be calculated by dividing the cardiac output (CO) by the patient’s body surface area (BSA).
CI = Cardiac Output / Body Surface Area
The CI is a useful hemodynamic parameter because it takes into account a patient’s size, which is different in each patient.
This makes it possible to compare the cardiac output of two different people, even if they have different body sizes.
Hemodynamic Monitoring Normal Values
Understanding hemodynamic monitoring requires knowledge of what the normal values are for each parameter. This includes the following:
- Mean arterial pressure (MAP): 93 mmHg
- Central venous pressure (CVP): 2-6 mmHg
- Pulmonary artery pressure (PAP): 25/8 mmHg
- Pulmonary capillary wedge pressure (PCWP): 4-12 mmHg
- Systemic vascular resistance (SVR): 900-1400 dynes/sec/cm
- Pulmonary vascular resistance (PVR): 150-300 dynes/sec/cm
- Cardiac output (CO): 4-8 L/min
- Cardiac index (CI): 2-4 L/min/m2
If a patient’s hemodynamic values fall outside of the normal range, it may be indicative of a problem. For example, a low cardiac output can be indicative of heart failure, while a high pulmonary vascular resistance can be indicative of pulmonary hypertension.
Hemodynamic Monitoring Practice Questions:
1. What are the three values used to evaluate the forces influencing blood pressure?
(1) CVP (central venous pressure), (2) PAP (pulmonary artery pressure), and (3) PCWP (pulmonary capillary wedge pressure).
2. What three factors affect blood pressure?
(1) The condition of the left ventricle (the pump), (2) The volume of blood in the cardiovascular system (the volume), and (3) The relative size of the intravascular space (
3. Which ventricle is composed of more muscle?
The left ventricle.
4. Where is the majority of the systemic blood stored in the body?
In the veins.
5. What happens during inspiration?
The drop in negative pressure in the thorax from -2 to -5 helps suck blood back toward the heart.
6. What is the Swan-Ganz catheter?
An invasive method of measuring pressure within the heart and lungs.
7. What is another name for the Swan-Ganz catheter?
The triple lumen catheter.
8. What is shock?
It is a lack of blood flow to any tissues/organs in the body.
9. What is the distal lumen?
The fluid-filled line that transmits a wave of pressure from the tip of the catheter to the transducer.
10. What is a transducer?
A device that converts one form of energy to another. The transducer converts the pressure signal to an electrical signal then sends it on to the monitor.
11. What does the monitor amplify?
It amplifies the signal and displays digital readings and/or a waveform.
12. What does the distal port communicate with?
The pulmonary artery.
13. Which chamber of the heart does the pulmonary artery come out of?
The right ventricle.
14. If the catheter is properly inserted, where does it rest?
In a pulmonary arteriole.
15. What can the distal port help us measure?
Problems that originate in the lungs. For example, pulmonary edema.
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16. What is PCWP?
It stands for pulmonary capillary wedge pressure. It reflects what is going on with the left side of the heart.
17. What happens when the balloon is inflated?
It wedges in an arteriole and is able to obtain a pressure.
18. Where is the closest location that we can get to the left side of the heart?
The pulmonary arteriole.
19. The proximal port is also known as what?
The central venous pressure port.
20. Where is the CVP port located?
At the top of the right side of the heart, where the superior vena cava goes into the right atrium.
21. The lumen opens how many centimeters from the catheter’s port?
30 cm
22. How is cardiac output measured?
By injecting a bolus of saline at a known temperature that is less than the body’s, into the proximal lumen.
23. What does the SVO2 measurement tell us?
How much oxygen the body is using.
24. What is a normal SVO2 value?
70%
25. What measurement is the closest to the left side of the heart?
PCWP
26. What is the formula for cardiac output?
CO = HR x SV
27. Where can you obtain the PaO2?
In a blood gas sample.
28. Where can you find the PVO2?
Mixed venous blood obtained from the distal (PA) port of a Swan-Ganz catheter.
29. Where is the SVO2 obtained from?
The optical module connector in the top of the line Swan-Ganz catheter.
30. VO2 is the amount of what?
Oxygen that the body extracts from the blood every minute in order to feed the tissues.
32. What blood vessel comes in at the top of the right heart?
The superior vena cava.
33. What drains into the superior vena cava?
Internal jugular vein.
34. Where would the first choice be for the insertion of the Swan-Ganz catheter?
The internal jugular vein and subclavian vein because they are a direct shot into the right atrium (veins closest to the right side of the heart).
35. What pressure can be taken when the catheter is in the right atrium?
The central venous pressure (CVP).
36. What is a normal CVP?
The average = 0 – 5 mmHg. The normal range = -2 – +12 mmHg.
37. After the catheter is in the right atrium, where does it go next?
Through the tricuspid valve into the right ventricle.
38. Why does the waveform change as soon as the catheter moves thru the tricuspid valve?
Because the pressure recorded within right ventricle is dramatically higher than within the right atrium.
39. What is a normal right ventricle pressure for systolic?
15-28 mmHg
40. What is a normal right ventricle pressure for diastolic?
0-8 mmHg
41. What is the normal systolic pulmonary artery pressure?
15-30 mmHg
42. What is the normal diastolic pulmonary artery pressure?
4-12 mmHg
43. What is the normal mean pulmonary artery pressure?
6-18 mmHg
44. What does the dicrotic notch represent?
The closure of the aortic & pulmonic valves @ the end of systole
45. What does it indicate when there is no dicrotic notch?
You may have to reposition the catheter or the patient was possibly moving.
46. What happens each time the mitral valve opens?
There is a direct communication between the catheter tip and the left ventricle via
47. What is a normal mean of PCWP?
6-12 mmHg
48. How do we know if someone is in shock?
They will demonstrate the following: decreased urinary
49. What does cardiogenic mean?
Beginning at the heart.
50. What is cardiogenic shock?
Left ventricular failing as a pump.
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51. What pressure is closest to the left ventricle?
PCWP
51. Patients with CHF will have what?
An increased PCWP.
52. What is the most common cause of shock?
The inability of the left ventricle to produce adequate stroke volume.
53. What is stroke volume?
It is the amount of oxygenated blood pumped out of the heart during systole.
54. In an adult, what is the average volume for each heartbeat?
60 – 130 mL/beat.
55. What is an infarction?
Dead muscle.
56. What are some disorders that can cause cardiogenic shock?
(1) Infarction of more than 40% of the left ventricular muscle, (2) CHF, (3) Cardiac tamponade, (4) Chest trauma.
57. What is cardiac tamponade?
Air or fluid in the pericardial sac.
58. How do you know that a patient has CHF based on their chest x-ray?
Measure the CT ratio and if it is > 50%, CHF is likely.
59. What happens when left ventricular failure gets worse?
Blood begins to back up into the left atrium.
60. What pressure is measured in pulmonary arteriole?
PCWP
61. Which factors are not affected by cardiogenic shock?
The skin’s color and temperature.
62. What does peripheral edema cause?
An increase in heart rate.
63. What can happen if you give a patient too much positive pressure on a ventilator?
It can cause cardiac tamponade (because it will squeeze the heart), among other things.
64. How is cardiac output affected
The left ventricle is failing so cardiac output is decreased.
65. What drugs would you give to increase cardiac output?
Positive Inotropes (digitalis, digoxin), which will increase the contractility of the heart.
66. What is the total amount of blood volume in the venous system is?
64%
67. Venous return is the amount of blood volume returning to the?
Right heart.
68. The patient cardiac index is the cardiac output based on what?
Actual body size.
69. What is end-systolic pressure?
The amount of blood in the ventricle after ejection.
70 What is end-diastolic pressure is?
The amount of blood in the ventricle after filling.
71. What does cardiac tamponade
It restricts the blood entering the heart.
72. What is the Fick equation?
CO= VO2/C(a-v)O2 x 10
73. What is the normal right atrial pressure (RAP)?
2 to 6
74. In general, PAP is concerning what?
The lungs.
75. In general, PCWP is concerning what?
The left heart.
76. In general, CVP is concerning what?
The right atrial pressure or fluid levels.
77. The systemic artery blood pressure (SABP) generally looks at what?
The blood pressure throughout the body.
78. What is preload?
The stretch on the ventricle muscle fibers before contraction.
79. What is afterload?
The resistance of external factors that oppose ventricular contraction.
80. Stroke volume is determined by what?
Preload, afterload, and contractility.
81. A decrease in potassium and sodium causes what?
Atrial fibrillation.
82. What is the procedure for placing an arterial line?
Assemble all equipment, perform the Allen’s test, drape the patient, inject 1% lidocaine, insert the catheter at a 30-degree angle, hold the needle and advance the catheter, remove the needle and secure, attach drip and observe the waveform.
83. What is the procedure for placing a pulmonary catheter?
It is done by the physician, check the balloon for patency, it is inserted into a selected sight until it reaches the right atrium, then inflate the balloon.
84. What are the common sites for placing a pulmonary catheter?
Subclavian or internal jugular vein.
85. What are the common sites for placing an arterial catheter?
Radial, brachial, or femoral arteries.
86. What is Systemic Vascular Resistance?
It is the pressure on the
87. What is Pulmonary Vascular Resistance?
It is the pressure on the pulmonary artery.
88. What factors affect the contractility of the heart?
Coronary blood flow, sympathetic nerve stimulation, Inotropic drugs, Physiologic depressants, damage to
89. What are the left atrial filling pressures?
Preload and PCWP.
90. What are the right atrial filling pressures?
The amount of blood in the right atrium or CVP.
91. What is MAP and what is the normal range?
It stands for mean arterial blood pressure and the normal value is 90
92. What is CVP?
It stands for central venous pressure.
93. What is PCWP and what is the normal range?
It stands for pulmonary capillary wedge pressure that the normal ranges
94. What is an increased CVP associated with?
Fluid overload, right ventricular failure, hypercapnia, valvular stenosis, PE, cardiac tamponade, pneumothorax, PPV, PEEP, left ventricular failure.
95. What is associated with an increased PAP?
Pulmonary hypercapnia, left ventricular failure, fluid overload.
96. What is associated with an increased PCWP?
Left ventricular failure, fluid overload, > 20 interstitial edema, >25 alveolar filling, >30 pulmonary edema.
97. What does an increase or decrease in CVP represent?
An increase represents fluid overload, L-R shunt, cor pulmonale. A decrease represents hypovolemic shock.
98. Why should all blood pressure measurements be taken at the heart level?
To eliminate the effect of gravity on hydrostatic pressure.
99. What is the definition of stroke volume?
The volume of blood ejected from the heart with each beat.
100. How does heart rate affect diastolic pressure?
It changes the duration of diastole and the pressure continues to fall until the next systole.
101. This is an early sign of changes in circulating blood volume?
Changes in Pulse pressure.
102. Low pulse pressures can indicate what two things?
CHF and shock.
103. What is the average driving force in the arterial system throughout the cardiac cycle known as?
Mean arterial pressure
104. MAP can be used to calculate what?
SVR and PVR
105. What is the normal for MAP?
70-105
106.
Circulation to vital organs may be compromised and poor tissue perfusion.
107. What are the indications for Arterial cannulation?
It’s indicated for hemodynamically unstable patients, patients on vasoactive drips, patients with IAB, and perioperative patients.
108. What are the hazards of arterial cannulation?
Hemorrhage, thrombus, air embolism, systemic infection, site infection, arterial spasm, vascular occlusion.
109. Why is invasive hemodynamic monitoring needed?
Because clinical assessment alone may not accurately predict hemodynamics.
110. What must be considered before a catheter is placed in a patient?
The risk-benefit ratio of invasive monitoring.
111. What is hemodynamic monitoring performed to do?
To evaluate the intravascular fluid volume, cardiac/vascular function; and to identify sudden changes in hemodynamics.
112. Why is invasive monitoring needed?
To obtain an accurate evaluation of hemodynamics.
113. What type of patient may a physician want to place an arterial catheter in?
Those with significant hemodynamic instability or the need for frequent arterial blood draws.
114. What conditions are likely candidates for arterial pressure monitoring?
Severe hypotension (shock) or HTN; respiratory failure,
115. What patient may benefit from arterial pressure monitoring?
Those in need of medication that affects blood pressure. Examples include vasodilators and inotropic agents.
116. Where is the arterial catheter usually placed?
Radial, ulnar, brachial, axillary, femoral.
117. Where is the arterial line most often placed and why?
The radial artery, because it is readily accessible/adequate collateral circulation.
118. What is low blood pressure a late sign of?
Deficits in blood volume or cardiac function.
119. What are the causes of hypotension?
Low blood volume (bleeding), cardiac failure/shock (heart attack), vasodilation (sepsis).
120. During the administration of what drugs should the diastolic pressure be watched carefully?
Vasodilators, such as sodium nitroprusside.
121. What are 6 causes of an increased central venous pressure?
Fluid overload, heart failure, pulmonary hypertension, tricuspid valve stenosis, pulmonary embolism, and increased venous return.
122. What are the 4 causes of a decreased central venous pressure?
Vasodilation, reduced circulating blood volume, leaks in pressure system/air bubbles, spontaneous inspiration.
123. When can pneumothorax occur during hemodynamic monitoring?
Then the catheter punctures the pleural lining.
124. What can the accidental opening of the central venous line stopcock allow and result in?
Air to enter the vein which can cause an air embolus.
125. What does the PAC allow the assessment of?
It allows the assessment of the filling pressures of the left side of the heart.
126. What are pulmonary artery catheters also called?
Swan-
127. What is the balloon at the tip of the catheter used for?
To float the catheter into position (into the right side of the heart and into the pulmonary artery) and obtain wedge pressure measurements.
128. What can resistance to pulmonary flow (increased PVR) be caused by?
129. What conditions cause an increased pulmonary vascular resistance?
Pulmonary emboli; acute/chronic lung disease; cardiac tamponade; left heart failure.
130. What should be immediately available at both the insertion and removal of a pulmonary artery catheter?
Lidocaine and emergency resuscitation equipment.
131. What should be optimized to decrease the risk of dysrhythmias?
Blood gases and serum electrolytes.
132. What is not normal and is an indication for obtaining a chest x-ray to assess the cause?
Catheter resistance
133. What are the factors that control blood pressure?
The heart, blood/fluid levels, and vessels.
134. The amount of blood pumped out of the left ventricle in a minute is known as what?
Cardiac Output
135. What is the cardiac Output normal range?
4 – 8 LPM
136. What is the formula for Cardiac Output?
CO= HR X SV
137. What is the volume or amount of blood ejected with each beat known as?
Stroke Volume
138. What is the stroke volume normal range?
60 – 130 mL/beat
139. What is the formula for stroke volume?
SV= CO / HR
140. The amount of blood that is ejected from the heart depends on what 3 things?
Preload, afterload, and contractility.
141. The right ventricle pumps against what?
Pulmonary vascular resistance.
142. The left ventricle pumps against what?
Systemic Vascular Resistance.
143. What happens when blood pressure is too low?
The tissues in the body won’t receive adequate oxygen.
144. What happens when blood pressure is too high?
It causes a strain on the heart and will eventually cause failure.
145. What is the pump that creates blood pressure?
The heart.
146. The distal port samples what type of blood?
Mixed venous blood.
147. What is the Respiratory Therapist’s job when assisting the physician with the insertion of a pulmonary artery catheter?
Set up the bag, zero, check the ports, inflate the balloon, and deflate the balloon.
148. The central venous pressure measures what 3 things?
Intravascular volume, venous return, and right ventricle preload.
149. What causes an increased central venous pressure?
Fluid overload, right ventricle failure,
150. What causes a decreased central venous pressure?
Hypovolemia and shock
151. A PCWP that is greater than 18 may represent?
Pulmonary vascular congestion
152. A PCWP that is greater than 30 may represent?
Pulmonary edema
153. What causes an increased PCWP?
Left heart failure, intravascular volume overload, cardiac tamponade/effusion, Obstructive LA tumor.
154. What are the factors which can cause an increased PVR?
Hypoxemia, acidosis, PPV/PEEP & vasoconstrictors.
155. What are the factors which can cause a decreased PVR?
Oxygen, Nitrogen, Alkalosis & vasodilators
156. What are the factors which can cause an increased SVR?
Hypovolemia, certain shocks & vasoconstrictive drugs
157. What are the factors which can cause a decreased SVR?
Vasodilators, morphine, certain shocks
158. What are the normal values for CVP?
2 – 6 mmHg
159. What are the normal values for RAP?
2 – 6 mmHg
160. What are the normal values for RVP?
20-30 / 0-5 mmHg
161. What are the normal values for PAP?
15-25 / 8-15 mmHg
162. What are the normal values for MPAP?
10-20 mmHg
163. What are the normal values for PCWP?
5-12 mmHg
164. What are the normal values for MAP?
85-115 mmHg
165. What are the normal values for PVR?
155 – 255 dynes*sec/cm5
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166. What are the normal values for SVR?
950 – 1300 dynes*sec/cm5
167. How many lumens do PAC catheters have?
4-6
168. Which part of the PAC rests in the right atrium for the CVP measurement?
The Proximal Lumen.
169. Where does the distal lumen rest?
In the pulmonary artery.
170. Which lumen measures the PAP, PCWP, and obtains mixed venous samples?
The distal lumen because it is in the pulmonary artery.
171. When inserting a PAC, how do you know if it’s in the right atrium?
The pressure should read 2-6 mmHg.
172. How does negative pressure affect the heart?
It increases venous return and preload.
173. What can cause an increased PCWP?
Left ventricular failure, hypervolemia, mitral valve stenosis, and technical causes.
174. What would be seen on a chest x-ray with a PCWP > 18 mmHg?
The onset of pulmonary vascular congestion.
175. What would be seen on a chest x-ray with a PCWP > 25 mmHg?
Obvious pulmonary edema.
FAQ
How is Hemodynamic Monitoring Done?
Hemodynamic monitoring is usually done using a catheter that is inserted into a blood vessel. The catheter is then connected to a monitor that displays the patient’s hemodynamic parameters.
This allows the medical team to closely monitor the patient’s condition and make changes to their treatment if necessary.
What are the Risks of Hemodynamic Monitoring?
Hemodynamic monitoring is a safe procedure with a low risk of complications. The most common complication is infection, which can occur at the site of the catheter insertion. This can be avoided by using sterile technique and keeping the area clean and dry.
What is PAOP in Hemodynamic Monitoring?
PAOP is short for pulmonary artery occlusion pressure. It is a measurement of the left ventricular filling pressure and is used to assess left heart function.
This measurement is helpful in determining the type of pulmonary edema, and whether or not it’s related to an abnormality of the heart
How is Hemodynamic Monitoring Used in Nursing?
Hemodynamic monitoring is a valuable tool for nurses. It can help to assess a patient’s condition and make decisions about their treatment.
It can also be used to monitor the effects of medication and other therapies, and to detect early signs of cardiovascular complications. Some examples include heart failure, arrhythmias, shock, and pulmonary edema.
Nurses work closely with doctors and respiratory therapists to ensure that a patient’s hemodynamic parameters are within an acceptable range.
Final Thoughts
Hemodynamic monitoring is the process of measuring the pressure inside the blood vessels. It’s an effective way to assess a patient’s cardiovascular status while monitoring the effects of treatment.
Respiratory therapists play an important role in hemodynamic monitoring, as they are often responsible for monitoring the patient’s parameters.
If you found this helpful, be sure to check out our guide on EKG interpretation. Thanks for reading and, as always, breathe easy, my friend.
Written by:
John Landry, BS, RRT
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
References
- Faarc, Kacmarek Robert PhD Rrt, et al. Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020.
- Faarc, Heuer Al PhD Mba Rrt Rpft. Wilkins’ Clinical Assessment in Respiratory Care. 8th ed., Mosby, 2017.
- Cardiopulmonary Anatomy & Physiology: Essentials of Respiratory Care. Cengage Learning; 7th edition, 2019.
- “Clinical Review: Update on Hemodynamic Monitoring – a Consensus of 16.” PubMed Central (PMC), 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3387592.
- “Hemodynamic Monitoring in the Critically Ill: An Overview of Current Cardiac Output Monitoring Methods.” PubMed Central (PMC), 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC5166586.