Non-Invasive Hemodynamic Monitoring: Does it Have a Role in

Non-Invasive Hemodynamic Monitoring:

Does it Have a Role in Shock Management?

Phillip D. Levy, MD, MPH

Asst. Professor of Emergency MedicineWayne State University/Detroit Receiving Hospital

Disclosures

• Consultant– ElectroSonics Medical, Inc

• Honorarium– SonoSite, Inc

• Research support (equipment only)– Cardiodynamics, Inc.

All material in this lecture has been prepared withoutexternal input or review and is free from bias

Learning Objectives

• To appreciate the importance of hemodynamics in shock

• To understand the shift away from invasive monitoring

• To recognize existing and emerging non-invasive modalities

Case Example

• 38 yo white female with history of IVDA presents to the ED with dyspnea– No chest pain or fever reported

• Initial vitals:HR 100; BP 90/50; RR 18; Temp 40.4 º C

• Lung exam: coarse breath sounds without wheezing, rales or rhonchi

• Cardiac auscultation: non-radiating II/VI DM

Case Example

• Initial differential– Endocarditis

– Sepsis

– Pneumonia (possible pneumocystis carini)

• Work-up initiated– CXR (-)

– Labs essentially nl

– Blood cultures obtained

Do I Really Need to Know Hemodynamics ?

Tissue Oxygen Delivery

• Oxygen content– CaO2 = (1.34 x Hgb x SaO2) + (0.0031 x PaO2)

• Perfusion– CO = HR x SV

– MAP = (CO x SVR) + CVP

– MAP = DBP + [SBP - DBP]/3

From: Schwaitzberg et al. J Pediatr Surg 1988;23;:05-9.

r=0.27, r2=0.07 r=-0.1, r2=0.0001

Can You Predict Perfusion Based on HR and MAP ?

From: Wo et al. Crit Care Med 1993;21:218-23.

But Perfusion is What Matters !

Hemodynamics of Perfusion

Afterload

Cardiac Output(CO)

HeartRate(HR)

StrokeVolume(SV)

Preload Contractility

(-) Diuretics(+) Volume Expanders

(-) Vasodilators(+) Vasoconstrictors

(-) Negative Inotropes(+) Positive Inotropes

(-) Neg.Chronotropes(+) Pos.Chronotropes

Invasive Hemodynamic Monitoring

• Pulmonary artery catheterization (PAC) 1,2

– Time honored mechanism

– Provides accurate information

– Questionable safety and benefits

• May not be ideal (or possible) in ED setting!

1 Swan et al. NEJM 1970;283:447-51.2 Silver et al. CHF 2004;10:17-21.

ESCAPE Trial 1,2

• Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness– Comparison of clinical assessment vs. PAC for severe ADHF

– At 6-month follow-up • No difference is primary endpoint (days alive)

• Slight improvement in secondary endpoints

– Stopped early by safety board !!

1 Shah et al. Am Heart J 2001;141:528-35.2 The ESCAPE Investigators and ESCAPE Study Coordinators* JAMA. 2005;294:1625-33.

ESCAPE – Adverse Events

The ESCAPE Investigators and ESCAPE Study Coordinators* JAMA. 2005;294:1625-33.

Is PAC Use Justified ?

Shah et al. JAMA 2005;294:1664-70.

Is PAC Use Justified ?

Shah et al. JAMA 2005;294:1664-70.

Non-Invasive Hemodynamic Monitoring Modalities

• Ultrasound – Cardiac output monitor (UsCoM)

– “Quick-look” echocardiography

– Central venous pressure estimation• Inferior vena cava

• Internal jugular vein

• Basilic vein

• Impedance cardiography (ICG)

• Esophageal doppler monitoring (EDM)

• Micro-impulse radar

Non-Invasive Measures of Oxygen Balance

• Pulse oximetry

• Near infrared spectroscopy (NIRS)

• Point of care lactate

• Gastric tonometry

• Sublingual capnography

• Orthogonal polymerized spectroscopy

Sublingual Testing

Healthy Volunteer Septic Shock

Orthogonal PolarizedSpectral Imaging

Ultrasound Cardiac Output Monitoring

• 10 parameters of cardiac function– Heart rate

– Cardiac output/index

– Stroke volume

– Systemic vascular resistance

Ultrasound Cardiac Output Monitoring

• Operator dependent– Requires considerable pressure

• Non-continuous monitoring

• Unreliable with pneumothorax

• No large correlation trials

• CE Mark but not yet FDA approved

USCOM

“Quick-Look”Echocardiography

Correlation with Cardiologist

Moore et al. Acad Emerg Med 2002;9:186-93.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Correlation with Cardiologist

Moore et al. Acad Emerg Med 2002;9:186-93.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

CVP Estimate: IVC

• Respiratory variance in IVC can be used to estimate CVP 1

IVC size Resp change RA pressure< 1.5 cm Total collapse 0-5 cm/H201.5-2.5 > 50 % collapse 5-101.5-2.5 < 50 % collapse 11-15>2.5 < 50 % collapse 16-20>2.5 No change > 20

1 Ma, OJ and Mateer JR. Emergency Ultrasound, p 111. 2003

Correlation with Cardiologist

Randazzo et al. Acad Emerg Med 2003;10:973-

7.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

CVP Estimate: IJ

• Based on visualization of blood column within IJ

• Find point of collapse and measure to angle of Louis

• Add 5 cm H20 toyield CVP

Lipton B. Am J Emerg Med 2000;18:432-

4.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

CVP Estimate: Basilic Vein

• Compression detectorattached to probe

• Measures external compression required to occlude vein

• Preliminary work

• Poor precision

Baumann et al. Resuscitation 2005;64:193-9.

Impedance Cardiography

• Emerging technology

• Utilizes variance in thoracic electrical impedance to estimate changes in blood volume– Impedance ↓ as fluid volume ↑

• Change in impedance over time used to calculate cardiovascular parameters

Aortic Blood Volume Changes Thoracic Impedance

Aorta Impedance Waveform Impedance Waveform (inverse)(inverse)

Determinants of Baseline and Dynamic Impedance

Base Impedance (ZBase Impedance (Z00))Thoracic blood and plasma volume

Muscle mass (cardiac and skeletal)

Lung tissue/air

Thoracic adipose tissue

Dynamic Impedance (Dynamic Impedance (∆∆∆∆∆∆∆∆Z)Z)Aortic blood volume and velocity

Aortic compliance

Pulmonary artery blood volume and compliance

Specific resistivity of blood

Strobeck et al. Congest Heart Fail. 2000;6:3-6.

ICG: Set-Up

• Low-amplitude signal transmitted across thorax– Filtered to remove respiratory variation

• ∆ impedance monitored – Variance represents ventricular ejection

ICG: Monitor Display

Comparison of ECG and ICG Waveforms

Osypka and Bernstein. AACN Clinical Issues. 1999;10:385-399.

ECGECG

dZdZ

dZdZ//dtdt

TimeTime

QQ = Ventricular = Ventricular depolarizationdepolarization

B = Opening aortic B = Opening aortic & pulmonic valves& pulmonic valves

C = Maximal slope C = Maximal slope dZ dZ

X = Closure aortic valveX = Closure aortic valve

Y = Closure of pulmonic Y = Closure of pulmonic valvevalve

O = Opening mitral O = Opening mitral

valve / rapid filling valve / rapid filling

of ventriclesof ventricles

ICG Measurements

• Cardiac function 1

– Stroke volume and cardiac index/output

• Afterload– Systemic vascular resistance

• Contractility 2,3

– Velocity index and systolic time ratio

• Fluid status 4

– Thoracic fluid content• Reciprocal of impedance 1 Albert et al. J Am Coll Cardiol 2003;41:211A.

2 Ranaei et al. J Card Fail 2002;8:S97.3 Parrott et al. CHF 2004;10:11-3.4 Peacock et al. CHF 2000;6:86-9.

Sample Status Report

Validation Studies

0.870.761.01

-0.240.19-0.43

0.840.890.80

ICG - FickTD - FickICG - TD

COYung et alPulm. HTN (39)

1.09-0.170.81ICG - TDCOVan de Water et al

Post CABG (53)

0.400.070.92ICG - TDCISageman et alPost CABG (20)

1.2-0.450.89ICG - TDCOZiegler et alMech vent.(52)

1.10.951.1

0.740.750.03

0.730.810.76

ICG - FickTD - FickICG - TD

CODrazner et al HF in cath lab(59)

1.380.080.89ICG - TDCOAlbert et alHF in ICU (33)

PrecisionBiasR valueComparisonParameterAuthorsPopulation (n)

Adapted from Yancy and Abraham . Congest Heart Fail. 2003;9:241-250.

Comparison of Cardiac Output Measurement Reproducibility

0.430.97ICG 3 vs. ICG 1

0.390.98ICG 3 vs. ICG 2

0.440.97ICG 2 vs. ICG 1

1.070.83TD 3 vs. TD 1

1.010.84TD 3 vs. TD 2

1.020.83TD 2 vs. TD 1

Stand. Dev.

(l/min)

Correlation

(R value)

Comparison

Van De Water JM, et al. Chest. 2003;123: 2028-33.

ICG Instead of PAC ?

• Reduction of PAC usage by 71% – 95% CI: 41.9 –91.6%

Silver et al. Congest Heart Fail. 2004;10(suppl 2):14-16.

Estimated Cost Savings Resulting from ICG Replacement

of PAC

Silver et al. Congest Heart Fail. 2004;10(suppl 2):14-16.

Esophageal Doppler 1,2

• First described in 1971

• Measures flow in descending aorta

1 DiCorte et al. Ann Thorac Surg. 2000;69(6):1782-6.2 Seoudi et al. J Trauma. 2003;55(4):720-5.

PreloadContractility (SV)AfterloadCardiac Output

Flow time 330-360 msecPeak Velocity 60-100 cm/secSVRI 800-1200 dynes/m2

CI 2.2-2.5 L/min/m2

Esophageal Doppler Monitoring

• Not tolerated by awake patients– Good for intubated patients in shock with elevated CVP

• Not continuous– Requires readjustment for each read

• Contraindicated with varices, caustic ingestion or perforated esophagus

MicroImpulse Radar

• Ultra-wide bandwidth (1-4 GHz)

• Short radar pulses (< 1 ns)– 2 MHz repetition rates

• Rapid digitization– Spatial accuracy ~ 5mm

• Non-ionizing– 50 mW RMS

• Enables non-contact monitoring– Developmental stages

Case Example

• After 2 hrs, pt deteriorates

• New vitals: HR 110; BP 70/40; RR 20; Temp 101 º F

• Lung exam remains unchanged

• Cardiac exam: increased rate

• Fluid resuscitation initiated– 1 L NS bolus

– Pt given vancomycin, tobramycin and cefepime

Simple Sepsis ?

Case Example

• ICG performed– CI = 1.8 L/min/m2

– SVR = 1600 dyne(s)(cm-5)

– TFC = 45 ohms

– LCWI = 2.4 kg(min)/m2

Case Example

• Dobutamine drip started at 10 mcg/kg/min

• Repeat BP at 15 min: 95/60

• ICG at 15 min– CI = 2.4 L/min/m2

– SVR = 1200 dyne(s)(cm-5)– TFC = 40 ohms– LCWI = 2.8 kg(min)/m2

Case Example

• Emergent echocardiogram obtained showing large vegetation on tricuspid valve

• Pt stabilized and transferred to ICU

Diagnosis = cardiogenic shock due to presumed

valvular insufficiency from endocarditits

Take Home Points

• Hemodynamic monitoring can impact patient care

• Non-invasive techniques are emerging and are likely to increase in importance

• The ED physician should be familiar with these tools to maximize outcomes