Cardiovascular Hemodynamics

Michael J. Lazar, MDMichael J. Lazar, MD

Cardiovascular Cardiovascular HemodynamicsHemodynamics

The Big PictureThe Big Picture

What is our goal in the ICU for What is our goal in the ICU for cardiac surgery patients?cardiac surgery patients?

End-organ perfusionEnd-organ perfusion– Keeping the blood pressure high enough Keeping the blood pressure high enough

to perfuse the tissuesto perfuse the tissues– Keeping the delivery of oxygen Keeping the delivery of oxygen

adequateadequate Oxygen ConsumptionOxygen Consumption Oxygen DeliveryOxygen Delivery

Cardiac Inotropes 04/21/23 2

Topics of the DayTopics of the Day

Blood PressureBlood Pressure Cardiac Output- why do we really Cardiac Output- why do we really

carecare What is and how do you fix Oxygen What is and how do you fix Oxygen

DeliveryDelivery When, why and how to use pressorsWhen, why and how to use pressors What medications do cardiac What medications do cardiac

patients go home onpatients go home on


General Range of Blood General Range of Blood PressurePressure

Postop SBP < 130 secondary to Postop SBP < 130 secondary to concerns for suture lines and concerns for suture lines and bleedingbleeding

Aneurysms SBP around 100Aneurysms SBP around 100 Preop levels +/- 10%Preop levels +/- 10%

– Gradual decrease to Gradual decrease to ““normalnormal”” levels levels Why do we care?Why do we care?


Blood Pressure and FlowBlood Pressure and Flow Organs are able to Organs are able to

autoregulate blood flow autoregulate blood flow within a given range of within a given range of pressurespressures

Outside this range they Outside this range they loose the ability to loose the ability to control their local control their local environment and environment and depend entirely on the depend entirely on the systemic pressuresystemic pressure

The brain and kidneys The brain and kidneys are particularly sensitive are particularly sensitive to alterations in blood to alterations in blood pressurepressure


Obviously pressure is only part Obviously pressure is only part of the storyof the story

The body will maintain blood pressure The body will maintain blood pressure at all costsat all costs

When cardiac output is low, pressure When cardiac output is low, pressure is increased by peripheral is increased by peripheral vasoconstrictionvasoconstriction

This allows a driving pressure to This allows a driving pressure to certain organs but reduces flow to certain organs but reduces flow to othersothers

How does this occur?How does this occur?Cardiac Inotropes 04/21/23 6

Distribution of Cardiac Distribution of Cardiac OutputOutput


• Increases in cardiac output are regulated by individual organs

• Within limits the flow can be modified by local changes in vascular tone

• At extremes of blood pressure, both high and low, local regulation is ineffective.

Flow By Organ SystemFlow By Organ SystemOrgans vary in range of blood flows and these are generated by adjustments in the tone of the resistance arteries and arterioles of the organ vessels

Brain Heart Gut Renal MuscleSkinBone

ml/min per 100 g--------------------------------------------------------------------------------Basal 60 75 100 400 5 10 3

Maximal 120 400 150 420 200 350 5

Minimal 55 70 30 30 3 3 2

Several patterns: high basal, little further at max: kidneylow basal, high max: skeletal muscle, skinbasal near minimal: heart, brain Cardiac Inotropes 04/21/23 8

Detecting a problemDetecting a problem

blood pressure blood pressure compensatory sympathetic stimulation compensatory sympathetic stimulation

– tachycardia tachycardia – sweating sweating – vasoconstriction vasoconstriction

organ dysfunction organ dysfunction – mental state mental state – urine output urine output

tissue hypoxia tissue hypoxia – pH pH – lactatelactate


Expected values following Expected values following cardiac surgerycardiac surgery

Mean arterial pressure (MAP)Mean arterial pressure (MAP) 70–95 mm Hg70–95 mm Hg

Systolic blood pressure (SBP)Systolic blood pressure (SBP) 90–140 mm Hg90–140 mm Hg

Right atrial pressure (RAP)Right atrial pressure (RAP) 5–15 mm Hg5–15 mm Hg

Left atrial pressure (LAP)Left atrial pressure (LAP) 5–15 mm Hg5–15 mm Hg

Cardiac index (CI) = CO/BSACardiac index (CI) = CO/BSA 2.0– 4.4L/min2.0– 4.4L/min

Systemic vascular resistanceSystemic vascular resistance (SVR) (SVR) SVR = (MAP - RAP/CO) x SVR = (MAP - RAP/CO) x

8080

SVRI = (MAP - RAP / CI) x 80SVRI = (MAP - RAP / CI) x 80 1400–2800 1400–2800 dyn·s·cm5/m2dyn·s·cm5/m2




care?care? What is and how do you fix Oxygen What is and how do you fix Oxygen


patients go home on?patients go home on?


Oxygen DeliveryOxygen Delivery

The body needs oxygen to liveThe body needs oxygen to live Oxygen delivery is the bodyOxygen delivery is the body’’s capacity to s capacity to

deliver this oxygendeliver this oxygen The delivered oxygen must be more than The delivered oxygen must be more than

the oxygen consumed the oxygen consumed SVO2 as the gold standard for delivery SVO2 as the gold standard for delivery

consumption mismatchconsumption mismatch Ideally we would rather increase oxygen Ideally we would rather increase oxygen

delivery rather than decrease consumption delivery rather than decrease consumption -- How? -- How?



Oxygen Delivery

(DO2)

Cardiac Output(CO)

Oxygen Content



DO2 = Oxygen Content x Cardiac OutputDO2 = Oxygen Content x Cardiac Output

=(1.38 x =(1.38 x HgbHgb x x SaOSaO22 + Pa0 + Pa022 x .0031) x x .0031) x HRHR x x SV SV

x 10x 10

Things to fix :Things to fix :1.1. HemoglobinHemoglobin

2.2. SaturationSaturation

3.3. Cardiac OutputCardiac Output



Oxygen Delivery

(DO2)

Cardiac Output(CO)

Oxygen Content

Heart Rate(HR)

Stroke Volume(SV)

Hemoglobin(Hgb)

Hemoglobin Saturation

(PaO2)


Oxygen ContentOxygen Content

Hemoglobin – Transfuse to Hemoglobin – Transfuse to ≈ 10 g/dL≈ 10 g/dL– Most efficient delivery of oxygen Most efficient delivery of oxygen

through capillary bedsthrough capillary beds– pAO2 contributes little to oxygen pAO2 contributes little to oxygen

deliverydelivery Oxygen Saturation ≈ 100%Oxygen Saturation ≈ 100%

– Concern for oxygen toxicityConcern for oxygen toxicity– Increased PEEP can decrease CO (best Increased PEEP can decrease CO (best

PEEP)PEEP)


Importance of Importance of HemodynamicsHemodynamics

Oxygen Delivery

(DO2)

Cardiac Output(CO)

Oxygen Content

Heart Rate(HR)

Stroke Volume(SV)

Hemoglobin(Hgb)

Hemoglobin Saturation

(PaO2)


Importance of Importance of HemodynamicsHemodynamicsCardiac Output

(CO)

Heart Rate Stroke Volume

Preload Contractility Afterload


The Starling CurveThe Starling Curve

Different lines Different lines represent represent different different contractile contractile statesstates

Volume status Volume status moves the moves the patient along patient along each line each line


Wedge PressureWedge Pressure

The wedge is an estimate of the End The wedge is an estimate of the End Diastolic Diastolic PressurePressure of the Left of the Left VentricleVentricle

This is in turn an estimate of the End This is in turn an estimate of the End Diastolic Diastolic VolumeVolume of the LV of the LV

This is the preload from the startling This is the preload from the startling curve.curve.


How do we measure LV preload?How do we measure LV preload?

The Gold StandardThe Gold Standard

TTE – TTE – Transthoracic Transthoracic echocardiogramechocardiogram

TEE – TEE – Transesophageal Transesophageal echocardiogramechocardiogram

Direct Direct visualization of visualization of the Left the Left VentricleVentricle


Mitral RegurgitationMitral Regurgitation


Aortic StenosisAortic Stenosis



(CO)




The Starling CurveThe Starling Curve Afterload is the Afterload is the

force the heart force the heart beats againstbeats against

No blood is ejected No blood is ejected until vascular until vascular resistance is resistance is overcomeovercome

As afterload is As afterload is reduced, more of reduced, more of the cardiac energy the cardiac energy is used to eject is used to eject blood.blood.


How do we measure How do we measure Afterload?Afterload?

Systemic vascular Systemic vascular resistanceresistance

SVR = (MAP - SVR = (MAP - RAP/CO) x 80RAP/CO) x 80

This is a This is a calculated number calculated number depends on each depends on each of the parameters of the parameters of the equation.of the equation.



(CO)






carecare What is and how do you fix Oxygen What is and how do you fix Oxygen


patients go home onpatients go home on


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications Dopamine Dopamine

MedicationMedication Clinical effectClinical effect Adverse Adverse effecteffect

Dosing(IVDosing(IV))

DopamineDopamine At 2–3 µg/kg/min, mainly At 2–3 µg/kg/min, mainly renal vasodilation via renal vasodilation via dopaminergic receptors dopaminergic receptors

At 4–10 µg/kg/min, mainly At 4–10 µg/kg/min, mainly positive inotropic and positive inotropic and chronotropic effects via beta1 chronotropic effects via beta1 receptorsreceptors

At >10 µg/kg/min, mainly At >10 µg/kg/min, mainly raises BP and SVR via alpha raises BP and SVR via alpha receptorsreceptors

Receptor stimulation overlapReceptor stimulation overlap

Raises Raises myocardial O2 myocardial O2 consumptionconsumption

ArrhythmogeniArrhythmogenic c

2.0–20 2.0–20 µg/kg/min µg/kg/min


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications Epinephrine Epinephrine

MedicationMedication Clinical effectClinical effect Adverse effectAdverse effect Dosing(IV)Dosing(IV)

EpinephrineEpinephrine Positive inotropePositive inotrope

Positive chronotropePositive chronotrope

At low doses, causes At low doses, causes vasodilation from vasodilation from beta2 activitybeta2 activity

>2µg/min raises BP >2µg/min raises BP via increasing alpha; via increasing alpha; activityactivity

Increases Increases myocardial O2 myocardial O2 consumptionconsumption

TachycardiaTachycardia

Arrhythmogenic Arrhythmogenic

High doses can High doses can exacerbate exacerbate metabolic acidosis metabolic acidosis from alpha effectfrom alpha effect

0.008–0.06 0.008–0.06 µg/kg/minµg/kg/min

(0.5–4.0 (0.5–4.0 µg/min)µg/min)


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications Norepinephrine Norepinephrine


NorepinephriNorepinephrinene

Raises BP and Raises BP and SVR SVR

Less positive Less positive inotropy inotropy

Increases myocardial Increases myocardial O2 consumptionO2 consumption

Intense Intense vasoconstriction can vasoconstriction can lead to visceral and lead to visceral and renal ischemia renal ischemia

Exacerbates metabolic Exacerbates metabolic acidosis by increasing acidosis by increasing anaerobic glycolysis anaerobic glycolysis and lactate production and lactate production

Exacerbates Exacerbates hyperglycemia hyperglycemia

0.03–0.3 0.03–0.3 µg/kg/minµg/kg/min

(2.0–20 (2.0–20 µg/min) µg/min)


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications PhenylephrinePhenylephrine


PhenylephriPhenylephrinene

Raises BP and SVRRaises BP and SVR

Often reflex decrease Often reflex decrease in HRin HR

Useful in patients Useful in patients with high cardiac with high cardiac index and severely index and severely vasodilated vasodilated

Increases Increases myocardial O2 myocardial O2 consumptionconsumption

Tolerance Tolerance develops develops

Can cause visceral Can cause visceral and renal ischemiaand renal ischemia

Can exacerbate Can exacerbate metabolic acidosis metabolic acidosis

0.15–3.0 0.15–3.0 µg/kg/min µg/kg/min

(10–200 (10–200 µg/min) µg/min)


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications MilrinoneMilrinone

MedicationMedication Clinical effectClinical effect Adverse Adverse effecteffect

Dosing(IV)Dosing(IV)

MilrinoneMilrinone Positive inotropePositive inotrope

Decreases SVRDecreases SVR

Decreases pulmonary vascular Decreases pulmonary vascular resistance (ideal for RV failure) resistance (ideal for RV failure)

Decreases coronary vascular Decreases coronary vascular resistance resistance

Most favorable effect on Most favorable effect on myocardial O2 consumption myocardial O2 consumption

Hypotension Hypotension Loading Loading dose: 50–75 dose: 50–75 µg/kg µg/kg

MaintenanceMaintenance: 0.25–0.75 : 0.25–0.75 µg/kg/min µg/kg/min


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications NitroprussideNitroprusside

MedicationMedication Clinical effectClinical effect Adverse effectAdverse effect Dosing(IVDosing(IV))

NitroprussidNitroprusside e

Arterial Arterial vasodilatationvasodilatation

Increases venous Increases venous capacitancecapacitance

Decreases SVR and Decreases SVR and PVR PVR

Rapid onset Rapid onset

Short half-life Short half-life

Reflex tachycardiaReflex tachycardia

Inhibition of hypoxic Inhibition of hypoxic pulmonary pulmonary vasoconstriction ( V/Q vasoconstriction ( V/Q mismatch )mismatch )

TachyphylaxisTachyphylaxis

Cyanide toxicity Cyanide toxicity –Metabolic acidosis Metabolic acidosis –MethemoglobinemiaMethemoglobinemia

Thiocyanate toxicity Thiocyanate toxicity –Seizures Seizures –PsychosisPsychosis

0.3–10 0.3–10 µg/kg/minµg/kg/min

Usual Usual dose: 0.3–dose: 0.3–4.0 4.0 µg/kg/min µg/kg/min


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications NitroglycerinNitroglycerin

MedicationMedication Clinical effectClinical effect Adverse effectAdverse effect Dosing(IVDosing(IV))

Nitroglycerin Nitroglycerin Increases venous Increases venous capacitance (major effect) capacitance (major effect)

Coronary vasodilatation Coronary vasodilatation

Decreases SVR and PVR Decreases SVR and PVR (less than nitroprusside (less than nitroprusside

Tolerance can Tolerance can occur with occur with continuous dosing continuous dosing

MethemoglobineMethemoglobinemiamia

0.1–10 0.1–10 µg/kg/min µg/kg/min

(10–700 (10–700

µg/min)µg/min)


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications CalciumCalcium

MedicatioMedicationn

Clinical effectClinical effect Adverse effectAdverse effect Dosing(IVDosing(IV))

CalciumCalcium Positive inotropePositive inotrope

Stabilizes myocardial Stabilizes myocardial membranes in setting of membranes in setting of hyperkalemia hyperkalemia

Temporary effect Temporary effect 1g CaCl 1g CaCl


Commonly Used Postoperative MedicationsCommonly Used Postoperative Medications TriiodothyronineTriiodothyronine


TriiodothyroninTriiodothyroninee

Positive inotropePositive inotrope

Decreases SVR Decreases SVR

Tachycardia Tachycardia

May be May be arrhythmogenic arrhythmogenic

Loading Loading dose: 0.4–dose: 0.4–0.8 µg/kg in 0.8 µg/kg in OR after x-OR after x-clamp clamp removed removed

MaintenancMaintenance: 0.1–0.12 e: 0.1–0.12 µg/kg/h µg/kg/h over 6 h over 6 h


HmmmHmmm ThatThat’’s way s way

too much too much information information to rememberto remember

Lets look at Lets look at how these how these drugs workdrugs work


Alpha receptorsAlpha receptors

alpha1 receptors:alpha1 receptors:– post synaptic cardiac - stimulation causes significant post synaptic cardiac - stimulation causes significant

increase in contractility without an increase in rateincrease in contractility without an increase in rate– effect more pronounced at low heart rateseffect more pronounced at low heart rates– slower onset and longer duration than beta1 response slower onset and longer duration than beta1 response

alpha2 receptors:alpha2 receptors: – presynaptipresynaptic in heart and vasculature c in heart and vasculature – appear to be activated by norepinephrine released by appear to be activated by norepinephrine released by

sympathetic nerve itself and sympathetic nerve itself and mediate negative feedbackmediate negative feedback – inhibition of further norepinephrine release inhibition of further norepinephrine release

post synaptic alpha1 and alpha2 receptors in post synaptic alpha1 and alpha2 receptors in peripheral vessels mediate vasoconstrictionperipheral vessels mediate vasoconstriction


Beta receptorsBeta receptors

post synaptic beta1 receptors are post synaptic beta1 receptors are predominant adrenergic receptors in predominant adrenergic receptors in heartheart

Stimulation causes Stimulation causes increased rateincreased rate and and force of cardiac contractionforce of cardiac contraction. .

post synaptic beta2 receptors in post synaptic beta2 receptors in vasculature mediate vasodilatationvasculature mediate vasodilatation


Dopamine receptorsDopamine receptors peripheral DA1 receptors mediate renal, peripheral DA1 receptors mediate renal,

coronary and mesenteric arterial coronary and mesenteric arterial vasodilatation and a natriuretic response vasodilatation and a natriuretic response

DA2 receptors: DA2 receptors: – presynaptic receptors found on nerve endings presynaptic receptors found on nerve endings – inhibit norepinephrine release from sympathetic inhibit norepinephrine release from sympathetic

nerve endingsnerve endings– inhibit prolactin release and may reduce inhibit prolactin release and may reduce

vomiting vomiting stimulation of either DA1 or DA2 receptors stimulation of either DA1 or DA2 receptors

suppresses peristalsis and may precipitate suppresses peristalsis and may precipitate ileusileus


Receptor pharmacologyReceptor pharmacology

AgentAgent AlphaAlpha11 AlphaAlpha22 BetaBeta11 BetaBeta22

DopamineDopamine

DobutamineDobutamine ++ ++ ++++++++ ++++ 00

DopamineDopamine ++/+++++/+++ ?? ++++++++ ++++ ++++++++

EpinephrineEpinephrine ++++++++ ++++++++ ++++++++ ++++++00

NorepinephrineNorepinephrine ++++++ ++++++ ++++ ++ 00

PhenylephrinePhenylephrine ++++++++ ++++++ ++ ++ 00


Receptor pharmacologyReceptor pharmacology

DopamineDopamine

DobutamineDobutamine

EpinephrineEpinephrine

NorepinephrineNorepinephrine

PhenylephrinePhenylephrine

MilrinoneMilrinone

VasopressinVasopressin


Little bit of everythingLittle bit of everything

BetaBeta

Alpha, BetaAlpha, Beta

Apha, small betaApha, small beta

AlphaAlpha

Like betaLike beta

Like alphaLike alpha

Putting It All TogetherPutting It All Together

Treatment of low cardiac Treatment of low cardiac output (CI < 2.0–2.2 L/min/m2)output (CI < 2.0–2.2 L/min/m2)

1.1. Consider surgical complications, Consider surgical complications, including including Coronary graft occlusionCoronary graft occlusion Valve malfunctionValve malfunction TamponadeTamponade BleedingBleeding Coronary spasmCoronary spasm



2.2. Optimize heart rate and rhythm Optimize heart rate and rhythm

– Increase rate to 90–100 beats per Increase rate to 90–100 beats per minuteminute

– Atrial pacing if no heart blockAtrial pacing if no heart block

– A-V pacing if heart block existsA-V pacing if heart block exists



3.3. Low blood pressureLow blood pressure (SBP <100 mm Hg or MAP <70 mm Hg)(SBP <100 mm Hg or MAP <70 mm Hg)

– If LAP * <15 mm Hg and HCT 25, administer If LAP * <15 mm Hg and HCT 25, administer Ringer's lactate or hetastarchRinger's lactate or hetastarch

– If LAP <15 mm Hg and HCT <25, administer If LAP <15 mm Hg and HCT <25, administer PRBCsPRBCs

– If LAP 15 mm Hg, start dopamine or other If LAP 15 mm Hg, start dopamine or other inotropic agent, then add nipride when MAP >70 inotropic agent, then add nipride when MAP >70 mm Hgmm Hg


Treatment of low cardiac Treatment of low cardiac output output (CI < 2.0–2.2 L/min/m2)(CI < 2.0–2.2 L/min/m2)

4.4. Normal or high blood pressure Normal or high blood pressure (SBP >100 mm Hg or MAP >70 mm Hg)(SBP >100 mm Hg or MAP >70 mm Hg)

– If LAP <15 mm Hg and HCT 25, administer If LAP <15 mm Hg and HCT 25, administer

Ringer's lactate or hetastarch, plus nipride or Ringer's lactate or hetastarch, plus nipride or other vasodilatorother vasodilator

– If LAP <15 mm Hg and HCT <25, administer If LAP <15 mm Hg and HCT <25, administer PRBCs, plus nipride or other vasodilatorPRBCs, plus nipride or other vasodilator

– If LAP 15 mm Hg, administer nipride/other If LAP 15 mm Hg, administer nipride/other vasodilator and consider diureticvasodilator and consider diuretic


Treatment of low cardiac Treatment of low cardiac output output (CI < 2.0–2.2 L/min/m2)(CI < 2.0–2.2 L/min/m2)

5.5. If CI and BP still low, If CI and BP still low, place IABPplace IABP


http://www.arrowintl.com/images/acatscreen.jpg

When all else failsWhen all else fails

Remember that if Remember that if nothing more can be nothing more can be done about delivery, done about delivery, we can often do we can often do something about something about consumptionconsumption

Limiting stressors is a Limiting stressors is a startstart

Paralytics are a last Paralytics are a last resortresort


Oxygen ConsumptionOxygen Consumption

Fever 10%Fever 10% Shivering 50-100%Shivering 50-100% ET Suctioning 7-ET Suctioning 7-

70%70% Sepsis 50-100%Sepsis 50-100% Visitor 22%Visitor 22% Position Change Position Change

31%31% Weighing 36%Weighing 36%

Work of Breathing Work of Breathing 40%40%

Procedure 7%Procedure 7% MSOF 20 - 80%MSOF 20 - 80% Dressing Change Dressing Change

10%10% Bath 23%Bath 23% CXR 25%CXR 25%




care?care? What is and how do you fix Oxygen What is and how do you fix Oxygen


patients go home on?patients go home on?


Beta-BlockersBeta-Blockers

Beta-blockers should be used as a Beta-blockers should be used as a first-line medication to prevent first-line medication to prevent postoperative atrial fibrillation postoperative atrial fibrillation

Researchers found that beta-blockers Researchers found that beta-blockers used in patients undergoing heart used in patients undergoing heart surgery decreased the incidence of surgery decreased the incidence of post-operative atrial fibrillation (AF) post-operative atrial fibrillation (AF) and shortened hospital stay and shortened hospital stay


Discharge MedicationsDischarge Medications

Metoprolol 50mg PO BIDMetoprolol 50mg PO BID ECASA 325mg PO daily ECASA 325mg PO daily

or orASA 81mg & Plavix 75mg dailyASA 81mg & Plavix 75mg daily

ACE inhibitor if neededACE inhibitor if needed Norvasc 5mg PO dailyNorvasc 5mg PO daily Imdur 30mg PO dailyImdur 30mg PO daily No routine nitrates or calcium channel No routine nitrates or calcium channel

blockersblockers


Discharge MedicationsDischarge Medications

Coumadin 5mg dailyCoumadin 5mg dailyreally dosed by INR and followed with coumadin clinicreally dosed by INR and followed with coumadin clinic

Coumadin 5mg dailyCoumadin 5mg dailyAmiodarone 200mg BIDAmiodarone 200mg BID– Then 200 daily for 3 monthsThen 200 daily for 3 months

Lasix 40mg dailyLasix 40mg dailyKDur 40meq dailyKDur 40meq daily


Thank YouThank You

Cardiac WorkCardiac Work

minute work of the heart = HR x SV x minute work of the heart = HR x SV x developed pressure, developed pressure,

A rise in heart rate, a rise in stroke A rise in heart rate, a rise in stroke volume, and a rise in aortic pressure volume, and a rise in aortic pressure all lead to a rise in oxygen all lead to a rise in oxygen consumption consumption


Placing a PA CatherterPlacing a PA Catherter

On a rare day at the beach in On a rare day at the beach in California, H.J.C. Swan noticed a California, H.J.C. Swan noticed a sailboat moving quickly despite the sailboat moving quickly despite the calm weather. This led to the initial calm weather. This led to the initial idea of devising a catheter with a idea of devising a catheter with a parachutelike or sail-like device parachutelike or sail-like device attached. attached.


When does the Wedge not When does the Wedge not Reflect Preload?Reflect Preload?

1.1.PAWP is less than LVEDPPAWP is less than LVEDP

2.2.PAWP is greater than LVEDPPAWP is greater than LVEDP

3.3.PAWP equals LVEDP, but LVEDP PAWP equals LVEDP, but LVEDP does not correlate with LVEDVdoes not correlate with LVEDV


*Ideal Situation--PAWP equals LAP equals LVEDP, and LVEDP is *Ideal Situation--PAWP equals LAP equals LVEDP, and LVEDP is proportional proportional to LVEDV. When this is true, PAWP can he used as a measure of left to LVEDV. When this is true, PAWP can he used as a measure of left ventricular preload. ventricular preload.


1.1.PAWP is less than LVEDPPAWP is less than LVEDP – Aortic regurgitation Aortic regurgitation – Reduced left ventricular compliance Reduced left ventricular compliance

2.2.PAWP is greater than LVEDPPAWP is greater than LVEDP

3.3.PAWP equals LVEDP, but LVEDP PAWP equals LVEDP, but LVEDP does not correlate with LVEDVdoes not correlate with LVEDV



1.1. PAWP is less than LVEDP.PAWP is less than LVEDP.

2.2. PAWP is greater than LVEDP.PAWP is greater than LVEDP. When catheter tip is in Zone 1 or 2;When catheter tip is in Zone 1 or 2;

may occur from artificial ventilation, with or without PEEP may occur from artificial ventilation, with or without PEEP or or

from volume depletion Atrial myxoma from volume depletion Atrial myxoma Thoracic tumors pressing on pulmonary veinsThoracic tumors pressing on pulmonary veins Mitral stenosis or regurgitationMitral stenosis or regurgitation Increased left ventricular compliance Increased left ventricular compliance

3.3. PAWP equals LVEDP, but LVEDP does not PAWP equals LVEDP, but LVEDP does not correlate with LVEDVcorrelate with LVEDV



1.1. PAWP is less than LVEDPPAWP is less than LVEDP

2.2. PAWP is greater than LVEDPPAWP is greater than LVEDP

3.3. PAWP equals LVEDP, but LVEDP does not PAWP equals LVEDP, but LVEDP does not correlate with LVEDVcorrelate with LVEDV


•Decreased left ventricular Decreased left ventricular compliance compliance •Increased left ventricular complianceIncreased left ventricular compliance •Increased right ventricular volume Increased right ventricular volume •Decreased right ventricular volume Decreased right ventricular volume •Pericardial tamponadePericardial tamponade •Removal of pericardium Removal of pericardium •Some drugs, e.g., isoproterenolSome drugs, e.g., isoproterenol •nitroglycerinnitroglycerin

•High LVEDV High LVEDV •Low LVEDV Low LVEDV •Tachycardia Tachycardia •Bradycardia Bradycardia •PEEP PEEP •Myocardial ischemia and Myocardial ischemia and infarction infarction •Myocardial hypertrophyMyocardial hypertrophy

Cardiovascular Hemodynamics

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