Responsible for:

 Central venous pressure monitoring

 Invasive hemodynamic monitoring

 IABP

 Monitor hemodynamic status and recognize

signs and symptoms of hemodynamic

instability

 SVO2 monitoring

Cardiac output

&

Stroke volume:

 Preload

 Afterload

 Contractility

 HR x Stroke volume (SV)

 Normal is 4‐6 L/min

 Index 2.5 – 3.5 L/min

Can be measured:

 Pulmonary artery catheter

 Echocardiogram

 Indirectly via functional

hemodynamics

May be normal associated with low SV & tachycardia!!!

 The amount of blood

ejected with each beat

 EDV – ESV = SV

 Typical EDV = 120 ml

 Typical ESV = 50 ml

 What is a normal SV?

 What happens to the

SV when afterload is

↑?

CO = HR x SV

Stroke Volume (prelad / afterload / contractility)

Preload

Myocardial

fiber length

Afterload (SVR)

Resistance the

heart has to

eject against

Contractility

How many myocardial

muscle fibers are available

to contract?

↑H+

↑CO2

↓O2 supply

 Defined as the stretching of

cardiac myocytes prior to

ejection

 Volume concept, measured

as pressure

 End diastole

 Volume of blood filling the

ventricle during diastole

 Indirectly measured in the right

side:

•  Right Atrial Pressure (RAP)

•  Central Venous Pressure (CVP)

•  Normal 2 – 6 mmHg

 Indirectly measured in the left side:

•  Pulmonary Artery Occlusive Pressure

• (PAOP)

•  Normal 8 – 12 mmHg

When would preload be

elevated?

 Heart failure

 Cardiogenic shock

 RV failure

 Pulmonary

hypertension

 Tricuspid stenosis

(CVP)

 Mitral stenosis (PAOP)

 Pericardial Tamponade

 Increasing PEEP on

vent

When would preload be

decreased?

 Hypovolemia

 Bleeding

 Venodilation

 Decreased venous

return

 After the

administration of

Morphine, NTG or beta

blockers!

 Normal value 2‐6 mm Hg

 Assesses right heart filling

pressures

Elevated:

 Hypervolemia

 RV failure

 Tricuspid regurg

 VSD

 Pulmonary HTN

 Cardiac Tamponade

Decreased:

 Hypovolemia

 Vasodilation

RAP/Stroke Volue

Normal RAP 2-6 mmhg 

RAP/CVP < 2

 AND low CO/CI, SV/SVI

Example: CVP 2 mmHg,

CI 1.8 L/min, SVR 1800

HYPOVOLEMIA

RAP/CVP > 6

 AND low CO/CI, SV/SVI

Example: CVP 14 mmHg,

CI 1.7 L/min, SVR 2100

RV FAILURE

RA / CVP 2-6mmhg

RV 15-30/0-8mmhg

PAP - 25/10

PAOP 8-12 mmhg

 Defined as the pressure or resistance

the ventricles must overcome to eject

blood

 Pulmonary vascular resistance (PVR)

‐Normal 90‐250 dynes/sec/cm‐5

 Systemic vascular resistance (SVR)

‐Normal 900‐1400 dynes/sec/cm‐5

MAP –CVP(80)

CO

When does afterload

increase?

 Cardiogenic shock

 Hypovolemic shock

 Bleeding

 Heart failure

 Cardiac Tamponade

Vasoconstriction

When does afterload

decrease?

 Septic shock (Warm)

 Anaphylactic shock

 Spinal/neurogenic

shock

 Insulin shock

Vasodilatation

 Force of ventricular ejection

 Difficult to measure

 Influenced by changes in preload & afterload

 “Inotrope” +/‐

Factors affecting

contractility:

 STEMI

 Sepsis

 Inadequate stretch

 ↑ Resistance

Vascular effects

from:

 IV fluids

 Vasopressors

 Inotropes

 Vasodilators

 Afterload

reducing agents

If a patient is

hypovolemic, what is the:

 Preload?

 Afterload?

 Cardiac Output?

 Stroke volume?

If a patient has worsening

left ventricular failure,

what is the:

 Preload?

 Afterload?

 Cardiac Output?

 Stroke volume?

 SVO2 65 – 75%

 Measured with a

pulmonary artery catheter

 ScvO2 > 70%

 Surrogate of mixed venous

 5 – 8% higher than SVO2

 If you cannot continuously

monitor:

▪ Draw sample from distal tip

of TLC/PICC (thorax) that is

positioned in the SVC

SaO2 95-100% from heart to system

ScVO2 >70% from system to heart

We normally extract about

25-30% to the tissues

Affected by 3 physiologic parameters:

“The Pump”

“The Lungs”

“The Hemoglobin”

SVo2 Normal : 60-76%

ScVO2 : >70%

Balance of O2 Delivery and O2 Demand

DECREASED O2 DELIVERY

(DO2)

 ↓Hemoglobin

 ↓C.O.

 ↓SaO2

INCREASED O2 CONSUMPTION

(VO2)

 Increased work of

breathing

 Shivering

 Fever

 Infection

 Agitation

 Nursing care

Contraindications:

-Tricuspid or

pulmonic

prosthetic valve

-Right heart mass

(thrombus or

tumor)

-Tricuspid or

pulmonic valve

endocarditis

- Left BBB

DIRECT MEASUREMENTS

 RAP

 PAS/PAD

 PAOP

 C.O.

 SVO2

CALCULATED MEASUREMENTS

 SV/SVI

 C.I.

 SVR

 PVR

 DO2

Phlebostatic Axis

Mid axillary line & 4th intercostal

• 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 & ½ AP diameter

 Remove all air from the IV solution

 Fill the drip chamber

 Flush the tubing

 Pressurize the bag (300 mm Hg)

 Fast flush the system

Dynamic Response

Square Wave Test

Dynamic Response

Square Wave Test

 Sluggish, artificially

rounded & blunted

appearance

 SBP erroneously low;

DBP erroneously high

 Causes: large air

bubbles in system,

compliant tubing,

loose/open connections,

low fluid level in flush bag

 Over responsive,

exaggerated, artificially

spiked waveform

 SBP erroneously high;

DBP erroneously low

 Causes: small air

bubbles, too long of

tubing, defective

transducer

 1. Measure at end‐expiration

 2. Measure the mean of the a – c wave

 3. Ensure transducer is leveled at the

phlebostatic axis

 4. Ensure line is reliable (square wave test)

 Consists of:

 a wave ‐ upstroke of atrial systole

 c wave ‐ often not visible

 v wave ‐ atrial diastole

when TV is closed

Read the avg. of the

“a” & “c” wave

or

Z‐point method‐end of

QRS complex

 RAP after P wave, in

the PR interval

 Measure mean of

the a wave

 PAOP after QRS

 Measure mean of

the a wave

Elevated systolic:

‐Normal pressure 25 mm Hg

 Pulmonary embolism

 COPD

 ARDS

 Hypoxia

 Pulmonary HTN

Elevated diastolic:

‐Normal 10 mm Hg

 Left ventricular failure

 Mitral valve dysfunction

 Cardiac tamponade

PA Diastolic

Reflective of LVEDP

except:

Mitral valve dysfunction

Pulmonary HTN

Right BBB

Aortic insufficiency

Pulmonic insufficiency

Decreased LV compliance

Normal 8‐12 mm Hg

**A wave = atrial contraction (after QRS)

C wave = mitral valve closure

V wave = atrial filling (after T wave)

 Preload indicator

 Assesses left heart filling

pressures

 Assume pressure & volume

are directly proportional

 However, that is only in a

normally compliant

ventricle!

 Disproportionate increase in

pressure w/ an increase in

volume

 Compliance is a change in

pressure for a given change

in volume

 Inject slowly and stop when the

waveform changes

 Never inject more than 1.5 ml of air

 Stop inflating the balloon if

resistance is met

 Inflate < 15 seconds

 Allow air to passively exit

If PA waveform does not change,

this may a sign of:

 Balloon rupture

 Tip of PA is in the RV or in PA

Elevated in:

 Mitral stenosis

 Mitral insufficiency

 Left ventricular failure

 Fluid/volume overload

 Cardiac tamponade

 Constrictive

pericarditis

 High levels of PEEP

 PAOP is < PAD

Elevated in:

 Mitral stenosis

 Mitral insufficiency

 Left ventricular failure

 Fluid/volume overload

 Cardiac tamponade

 Constrictive

pericarditis

 High levels of PEEP

 PAOP is < PAD

Signs in Zone 1 or 2:

‐ Damped paop waveform

‐ PAOP > PAD

‐ Absence of A and V waves

PA Catheters must

be placed in Zone 3

 Measure the mean

of the a ‐ c wave

Causes:

 Mitral /tricuspid

regurg

 Fluid overload

 Ventricular septal

rupture

PAOP/Stroke Volume

Normal PAOP 8-12 mm Hg

PAOP < 8 MM HG

 AND low CO/CI, SV/SVI

Example: CVP 2 mmHg,

CI 1.8 L/min, PAOP 4 mmHg,

SVR 1800

Hypovolemia

PAOP > 18 MM HG

 AND low CO/CI, SV/SVI

Example: CVP 15 mmHg,

CI 1.8 L/min, PAOP 18 mmHg,

SVR 1900

LV Failure

 Inflates during diastole

at the dicrotic notch

 Deflates during systole

 Coronary arteries are

fed during DIASTOLE

Contraindication:

‐ Aortic insufficiency

‐ Aortic aneurysm

 Increased coronary

artery perfusion

 Decreased O2 demand

 Increased O2 supply

 Decreased afterload

 Limb ischemia

 Incorrect timing

 Renal artery occlusion

 Infection