Hemodynamics Flashcards
1
Q
what is hemodynamics?
A
force by which blood circulates through the body.
2
Q
What does the term Hemodynamics describe?
A
the intravascular pressure and flow that occurs when heart muscle contracts and pumps blood through the body.
3
Q
What are the two techniques of hemodynamics?
A
invasive
noninvasive
4
Q
what is hemodynamics a combination of?
A
Cardiac output and blood pressure for effective tissue perfusion
5
Q
What are the two types of arterial pressures?
A
Systemic and Pulmonary
6
Q
what is preload?
A
Volume of blood within ventricle at end of diastole
Degree of muscle fiber stretching in the ventricles right before systole
7
Q
What is left ventricular preload reflected by?
A
PCWP
8
Q
What is right ventricular preload reflected by?
A
CVP
9
Q
What are factors that increase preload?
A
- exercise
- Hypervolemia
- Neuroendocrine excitement (sympathetic tone)
- AV fistula
10
Q
Why can an AV fistula cause an increase in preload?
A
An arteriovenous fistula can increase preload: AV shunts, and fistulas decrease the afterload of the heart. This is because the blood bypasses the arterioles which results in a decrease in the total peripheral resistance (TPR). AV shunts/fisulas increase both the rate and volume of blood returning to the heart.
11
Q
Factors that decrease. preload?
A
- Hypovolemia
- Narrowing or stenosis of valves
- Afib
12
Q
Factors that increase afterload?
A
- systemic resistance
- Aortic stenosis
- myocardial infarction
- Cardiomyopathy
- Polycythemia (increased blood viscosity)
13
Q
Factors that decrease afterload?
A
- decreased volume
- septic shock
- end stage cirrhosis
- vasodilators
14
Q
Why can septic shock decrease afterload?
A
Increased CO, decreased peripheral vascular resistance, third spacing due to vasodilation from histamine release, making capillaries more permeable.
15
Q
What is afterload?
A
the resistance the left ventricle must overcome to circulate blood
16
Q
what is contractility?
A
Strength of ventricular contraction
17
Q
what is inotropic?
A
force or energy of contraction, inotropic agent increases force of contraction
18
Q
What is chronotropic?
A
related to time, chronotropic agent changes rate of contraction
19
Q
what is stroke volume?
A
amount of blood ejected by the ventricles with contraction
20
Q
what is cardiac output?
A
HR x SV, determined by HR & rhythm, preload, afterload, contractility
21
Q
what is cardiac index?
A
Cardiac Index (CI): CO adjusted for BSA (CO/BSA)- more specific to each patient
22
Q
what do vasopressors do?
A
stimulates smooth muscle contraction of the capillaries and arteries
23
Q
what do ionotropes do?
A
increase the force of contraction of myocardial muscle
24
Q
what are some types of invasive monitoring?
A
- CVP
- ART
- Pulmonary Artery monitoring
25
How do you ensure accuracy with invasive monitoring?
- Equipment must be referenced and zero balanced to environment and dynamic response characteristics optimized
- Referencing: Positioning transducer so zero reference point is at level of atria of heart or Phlebostatic axis for cardiac pressure/systemic arterial readings
26
where is the Phlebostatic axis?
- 4th intercostal space
- midchest
- this is equivalent to the level of the right atrium
27
how do you zero a line?
-Open the stopcock to air, hit zero function on the monitor and digital returns to zero. Confirms that when pressure within system is zero, monitor reads zero
28
when do you zero a line?
- During initial setup of arterial line
- Immediately after insertion of arterial line
- When transducer has been disconnected from pressure cable or pressure cable has been disconnected from monitor
- When accuracy of values is questioned
29
what type of monitoring can use a central line?
-central venous pressure
30
What type of monitoring can use the PA?
- CVP
- PAP
- PAWP/PCWP
- PVR/PVRI
- SVR/SVRI
31
what type of monitoring can use the swan Ganz?
- CVP
- PAP
- PAWP/PCWP
- PVR/PVRI
- SVR/SVRI
- CO/CI
32
what does CVP measure?
Right atrial filling (preload)
33
what does pulmonary artery pressure measure?
Left atrial preload
34
what does pulmonary artery wedge pressure measure?
Left atrial pressure
35
What does pulmonary vascular resistance measure?
resistance of pulmonary bed
36
what does Systemic vascular resistance measure?
resistance of vascular bed (afterload)
37
Normal range of CVP
0-8mmHg
38
Normal range of Pulmonary artery pressure?
15-25/8-15
39
Normal range of pulmonary artery wedge pressure?
6-12mmHg
40
Normal range of pulmonary vascular resistance?
100-250dynes/sec/cm
41
Normal range of systemic vascular resistance?
800-1200dynes/sec/cm
42
Normal range of cardiac output?
4-8L/min
43
Normal range of cardiac index?
2.2-4L/min/M
44
what does central venous pressure reflect?
Reflects amount of fluid returning to the right side of the heart – preload
45
Fill in the blank:
| Right atrial and right ventricular are _______ at end diastole.
the same
46
How to get a CVP (3)
- transducing a central line
- attachment of a water filled column to the line
- Proximal lumen of Swan/PA line
47
how does spontaneous breathing ventilation affect CVP?
inspirations decrease CVP
48
How does Positive pressure ventilation affect CVP?
inspirations increase CVP
49
Risks Associated With CVP monitoring
- Superior Vena Cava perforation
- Guidewire induced arrhythmias
- Venous thrombosis
- Infection
50
What might a sudden decrease in CVP indicate?
- fluid deficit
| - hemorrhage
51
What might a sudden increase in CVP indicate?
- hypervolemia
| - HF
52
reasons for ART line?
- Severe Hypertension
- Severe Hypotension
- Respiratory Failure/shock
- Use of pressors
- Frequent ABG’s
53
what is the Allens test?
- Hold the hand up and clench and unclench the hand.
- Compress the radial & ulnar arteries.
- Lower the hand and relax.
- Quickly release the ulnar artery – color should return quickly (5-7 sec)
54
steps to obtain blood through ART line?
- Turn Stopcock so that it is OFF to the transducer. And open to the patient.
- Pull back on blood reservoir/syringe plunger until adequate discard is obtained.
- Insert specimen syringe into stopcock port and aspirate specimen
- Ice if needed, label and transport specimen
- Return blood in VAMP if present
- Flush Line Completely
55
What part of the ART line waveform should you look for?
Dichotic notch
56
What does a Dichotic notch indicate?
Aortic valve closure
57
Complications of art lines?
- Line Disruption
- Vasospasm
- Arterial Embolism
- Vascular compromise
- Line Identification errors
58
What is overdampening?
the loss of the dicrotic notch, usually caused by a clot in catheter tip or a bubble in the tubing
59
What is underdampening?
Extreme wave forms; usually caused by excessive tubing length, multiple stopcocks, tachycardia, High CO
60
What does under-dampening cause?
A systolic bp reported higher than it actually is, diastolic reported lower than it usually is
61
True or False?
Cuff pressures are the same as art line pressures
FALSE
Art line pressures are much more accurate
Art line pressures are often 5-10mmHg higher than cuff pressures
62
What is a pulmonary catheter used for?
-Provides hemodynamic information that cannot be obtained by physical assessment.
63
What do pulmonary catheters measure? (7)
- Stroke volume
- cardiac output
- intracardiac pressure
- pulmonary artery pressure
- systemic vascular resistance
- pulmonary vascular resistance
- mixed venous oxygen data from blood
64
What is PA diastolic pressure an indication of?
cardiac function and fluid volume status
65
What does monitoring PA pressures allow for?
therapeutic manipulation of preload
66
Advantages of swan ganz? (3)
- provides continuous hemodynamic monitoring
- easy to place
- the standard hemodynamic tool
67
Disadvantages of a swan Ganz? (4)
- Invasive and potentially harmful
- never been shown to demonstrate clinical benefit
- requires training to interpret waveforms and pressures
- requires knowledgable and continuous nursing care
68
What does a swan Ganz monitor?
CVP
PAP
Cardiac OP
69
Indications for use of a Swan Ganz? (6)
- Post MI
- Cardiac surgery/major surgery
- resuscitation
- shock
- pulmonary edema
- oxygen transport: ventilation and perfusion
70
Use of PA monitoring and measurement?
Guides management of patients with complicated cardiac, pulmonary, and intravascular volume problems
71
When do you obtain. measurement for a PA?
at end expiration
72
how do you obtain PAWP?
by inflating balloon with air until PA waveform changes to a PAWP waveform
DO NOT OVERINFLATE!!
73
how should the balloon be inflated?
slowly and for no more than 4 respiratory cycles or 8-15 seconds
74
What is the amount the balloon is inflated to?
1-1.5mLs
75
What does high PA and PAWP indicate?
Left sided heart failure
76
What does high PA pressure and normal PAWP indicate?
pulmonary disease
77
What does low PA pressure indicate?
low volume
78
What does low PAWP indicate?
fluid volume deficit
79
what does high PAWP indicate?
- fluid overload
| - Left ventricular failure
80
What does the the PA measure in relation to CVP?
right atrial
proximal port
reflects preload
blood sampling
normal:2-8
81
What does the PA measure in relation to PA pressure?
right ventricle
reflects preload of left side
normal: 25/10mmHg
82
What does the PA measure in relation to PAWP?
- reflects left ventricular pressure
| normal: 4-12mmHg
83
What does PA measure in relation to cardiac output?
the amount of blood pumped by the heart in one minute
4-6L/min
84
What does the PA measure in relation to SVR?
afterload
normal:800-1200 dynes
85
what does a decreased SVR indicate?
vasodilation
86
what is a drug or cause of decreased afterload?
Nipride
| shock states
87
What does a high SVR indicate?
vasoconstriction
88
what is a drug or cause of high SVR?
hypovolemia
| vasoactive agents
89
how does the PA measure CO? (3)
- right ventricular portion of the PA catheter generates heat signals produced from electrical impulses
- change in pulmonary artery blood temperature measured by the PA Cath thermistor
- calculates the average CO for the last 3-5minutes
90
what is a normal CO?
4-8L/minute
91
how often should you zero the monitor and vigileo?
once a shift
92
what is stroke volume?
blood ejected from the right ventricle per beat
low value indicates poor ventricular performance
93
what Is a normal stroke volume?
60-100mL/min
94
What type of patients is stroke volume variance used for?
ventilated patients
95
what do you adjust SVV for
arterial pulsations caused by volume change with positive pressure ventilation
96
what does a SVV of over 15% indicate?
hypovolemia
97
What is a normal SVV?
10-15%
98
what is a normal Cardiac index?
2.5-4L/min
99
what is a normal SVI?
33-47mL/beat
100
what is a normal SVR?
800-1200dynes-sec/cm
101
What is a normal SVRI?
1970-2390 dynes-sec/cm
102
what is a normal SVV?
<15%
103
what is a normal Scv02?
greater than or equal to 70%
104
what do watch for in relation to infection and sepsis?
- asepsis for insertion and maintenence of catheter and tubing mandatory
- change flush bag, pressure tubing, transducer, and stopcock every 96hours
105
what to watch for on PA catheter insertion?
ventricular dysrhythmias
106
what does it mean if the PA catheter cannot be wedged?
may need repositioning
107
reasons complications can occur
- Pulmonary infarction or PA rupture
- balloon rupture
- prolonged inflation
- spontaneous wedging
- thrombus or embolus formation
108
What types of baseline data need to be obtained to note sudden changes? (6)
- general appearance
- LOC
- skin color/temperature
- vital signs
- peripheral pulses
- UOP
109
examples of baseline biotechnology readings? (6)
- ECG
- Arterial BP
- CVP
- PA
- PAWP
- Sv02
110
what is ICP?
Intracranial pressure monitoring uses a device, placed inside the head.
111
what does the ICP monitor sense?
pressure inside the skull and sends measurements to a recording device
112
what is a normal ICP?
5-15mmHg
113
What are the 3 essential components of the skull?
- brain tissue
- blood
- CSF
114
what percentage of the brain does CSF take up?
10%
115
what percentage of the brain does intravascular blood take up?
12%
116
what percentage of the brain does brain tissue take up?
78%
117
What is cerebral perfusion pressure?
pressure needed to ensure blood flow to the brain
118
What is the formula to calculate CPP?
CPP=MAP-ICP
119
what is a normal CPP?
70-100mmHg
120
what is a CPP of less than 50mmHg associated with?
ischemia or brain death
121
where can ICP be measured?
- ventricles
- subarachnoid space
- epidural space
- brain parenchymal tissue
122
where is the reference point for the pressure transducer?
tragus of the ear
123
what is a normal ICP?
0-15mmHg
124
what is the gold standard for ICP monitoring?
ventriculostomy
125
True or False:
It is possible to control ICP by removing CSF
TRUE
ICP is based off the CSF in the brain, and if you remove some, this will lower the ICP
126
What is the biggest consideration with ICP monitoring?
infection risk
127
when should ICP be measured?
mean pressure at the end of expiration
128
what does an ICP monitor look similar to?
arterial BP
129
What can cause inaccurate ICP readings? (5)
- CSF leaks
- Obstruction in catheter
- differences in height of bolt/transducer
- kinks in tubing
- incorrect height of drainage system relative to patients reference point
130
What is the optimal level of CPP?
60 or above
131
what does a normal CPP indicate?
adequate vascular volume
132
What drives MAP?
vasopressors
fluids
133
Things that can minimize ICP? (3)
- sedation
- osmotic agents
- ventriculostomy
134
what are the commonly used vasopressors fro the maintenance of CPP? (4)
- Dopamine
- Norepinephrine
- Neosynephrine
- vasopressin
