1-8: Hemodynamic Monitoring Flashcards by Emily Tyner

What is the most important aspect of hemodynamic monitoring?

determination of the CO

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What is stroke volume

the amount of blood ejected from the ventricles in each heartbeat

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What can affect the stroke volume?

cardiac contractility (ejection fraction)
preload
afterload

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What is preload

also known as left ventricular end diastolic pressure (LVEDP) or CVP (RVP)
- the amount of ventricular stretch at the end of diastole

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What is afterload

also known as systemic vascular resistance (SVR)
- the amount of resistance the heart must overcome to open the aortic valve and push blood into systemic circulation

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What is cardiac output

the volume of blood ejected by the heart per minute

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What is the normal range for cardiac output?

4-8 L/min

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What is the equation for CO

SV x HR

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What are some causes of elevated CO?

stimulation of the sympathetic nervous system (pain, epi)
positive inotropic stimulation
hyperthyroidism
hypervolemia
anemia

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What are some causes of decreased CO?

an increased HR that doesn’t allow for adequate preload ( >150)
decreased HR
decreased myocardial contractility
increased afterload

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Why does increased afterload decrease CO?

afterload is SVR
the pressure in the ventricle (4-16) must be higher than the pressure in the aorta (80) to get forward flow
afterload is anything that makes it harder to get blood OUT of the heart.
Increasing afterload (SVR) is having a higher diastolic BP
if your ventricle has to work harder to push blood out of the heart, ultimately LESS blood will be let out.

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What is cardiac index?

CO / BSA

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What is the normal range for cardiac index?

2.5 - 4 L/m/m2
and these are hard values, if it hits 2.4, as a medic you need to do something

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What value will cardiac index fall below in cardiogenic shock?

1.8

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What is SvO2 and what is the range?

The saturation of hemoglobin on the venous side
normal saturation is 65-75%

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What do low and high levels of SvO2 mean?

low: more oxygen is jumping off at the tissues, which indicates a decreased tissue perfusion issue.

high: less oxygen is jumping off at the tissues, indicates decreased O2 consumption at the tissue level

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What affects preload?

intravascular volume
venous tone (size of the pipes)

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Right ventricular preload is the same as CVP, so has a range of:

2-8 mmHg

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Left ventricular pressure is the same as:

LVEDP

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What is the range for SVR?

800-1200

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What is the value for pulmonary vascular resistance?

<250 dynes/sec/cm5

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Can a single measurement be used in isolation to assess hemodynamics?

no, silly

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What are the parameters of hypotension?

SBP < 90
SBP decrease of >40 under baseline
MAP <65

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Is it possible for a patient to have a normal BP yet have hypoperfusion and be in shock?

yes

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What is the formula for shock index?

HR / SBP

What is the normal range for shock index?

0.5 - 0.7

What is the value of shock index that indicates early circulatory collapse and shock?

0.9

skin discoloration on what part of the body indicates poor perfusion (for adults vs. kids)

- adults: over knee/leg - kids: hands and feet

How many lumens does the Swan cath have and what are they?

4 lumens 1. proximal ( right atrial) 2. distal ( pulmonary artery) 3. balloon inflation port 4. infusion port

Transducers must be calibrated to:

ambient air pressure

What does the transducer ned to be placed level with? What is another name for it?

transducer must be level with the right atrium, also called the phlebostatic axis

How does the pressure reading correlate to the position of the transducer?

the higher the transducer, the falsely lower the pressure the lower the transducer, the falsely higher the pressure

How should the stopcock be when zeroing the transducer?

"off to the patient, open to the air"

When should you zero the transducer?

- whenever a reading is taken - insertion - change in the pts position

under what conditions do you leave the swan balloon inflated?

none, you silly goose

What are some complications that could occur DURING Swan catheter placement?

- dysrhythmia - pneumothorax - arterial puncture - mechanical injury (RV puncture) - kinking of the catheter

What are some complications that could occur AFTER Swan catheter placement?

- forward catheter displacement (aka spontaneous wedging) - backward catheter displacement (tip in RV) - pulmonary artery rupture - pulmonary artery infarction

How can spontaneous wedging be seen and avoided?

can be seen: waveform change, lose dichrotic notch prevented by: taping a reference strip to the monitor for transport

What should you do if you suspect forward catheter displacement?

- check to make sure the balloon is deflated - check for effect of position change (raise arm above head and cough) - turn the pt onto their left side - call the physician

what is the main concern regarding backward cath displacement of a swan catheter?

The catheter needs to be repositioned because catheter whip might cause arrhythmias

What are the parts of a CVP waveform and what do they mean? (be able to draw it out and label it)

"a" - produced when the atria contract. ***this is the beginning of the cycle*** "c" - caused by the closure of the tricuspid valve "x" and "y" - atrial diastole "v" - venous filling of right atrium

What is the CVP and ranges

Central venous pressure 2 - 8

What is the RAP and ranges

right atrial pressure 2 - 8

What do the CVP and RAP reflect?

the right ventricular end-diastolic pressure or PRELOAD

What causes elevated CVP/RAP?

**anything that blocks forward flow** - right sided heart failure - cardiac tamponade - pulmonary hypertension - volume overload - PPV

Causes of low CVP/RAP

- volume depletion - vasodilation - venous vasodilator

right ventricular pressure (RVP) normal range

15 - 30 ----------- 0 - 8

What causes elevated RVP?

** anything that causes higher pressures downstream of the RV** - pulmonary disease - hypoxemia - chronic heart failure - RV failure or infarction - ventricular septal defect

Causes of low RVP

- hypovolemia - vasodilation

normal values of PAP

15 - 30 ----------- 5 - 15

Causes of elevated PAP

- hypervolemia - pulmonary hypertension - PPV - cardiac tamponade - left ventricular failure

Causes of low PAP

- hypovolemia - vasodilation

what is the most amount of air used to inflate the swan catheter and when do you stop inflating it?

1.5 mL stop inflating when the waveform changes from PA to PAWP

Wedging should last no longer than _____

15 seconds

What is the range for wedge / PAWP / PCWP / PAOP?

4 - 12 mmHg

wedge pressure: in spontaneously breathing patients, inspiration is a ____ in pressure and expiration is a ____ in pressure

fall, rise

Where should the wedge pressure be taken?

at end expiration pressure (it is as close as it will get to atmospheric pressure and therefore provides the most accurate reading)

Causes of elevated wedge

**blockage of forward flow** - PPV - hypervolemia - left ventricular failure (CHF) - severe aortic stenosis

Causes of low wedge

- hypovolemia - vasodilation

All ranges: MAP CVP PAS PAD PAWP CO CI RVP PVR SVR

MAP (mean arterial pressure) 70-100 CVP (central venous pressure) 2-8 PAP (pulmonary arterial pressure) - systolic: 15-30 - diastolic: 5-15 PAWP (wedge) 4-12 CO (cardiac output) 4-8 L/min CI (cardiac index) 2.5-4 RVP (right ventricular pressure) - systolic: 15-30 - diastolic: 0-8 PVR (pulmonary vascular resistance) < 250 SVR (systemic vascular resistance) 800-1200

The causes of a dampened waveform are the same for an art line and swan cath except for one thing, what is it?

A spontaneous wedge can occur in a swan, causing dampened waveform

what is the treatment for a dampened waveform on swan?

- pull cath back to RA if it has spontaneously moved forward - pull cath back to PA if waveform indicates a spontaneous wedge and the balloon isn't inflated

Causes of right ventricular waveform:

- if the cath gets pulled to the right ventricle - RV waveform looks similar to v-tach

Causes of no waveform:

- stopcock turned off to the pt - catheter tip is clotted - monitor or system is set up incorrectly/ equipment not working

Which intercostal space is the phlebostatic axis located

4th

which reading indirectly reflects left atrial pressure and LVEDP?

wedge