This document discusses using echocardiography to measure stroke volume and cardiac output in ICU patients. It explains that stroke volume and cardiac output can provide early warning of circulation failure beyond what mean arterial pressure indicates. The document outlines how to obtain echocardiography images of the heart and left ventricle outflow tract to measure stroke volume using pulsed-wave Doppler. Stroke volume combined with heart rate can then be used to calculate cardiac output. Measuring stroke volume allows assessment of the effectiveness of fluid challenges, inotropes, or other therapeutic maneuvers.

1. ECHOCARDIOGRAPHY IN ICU
MEASUREMENT OF STROKE VOLUME AND CARDIAC OUTPUT
BÙI GIO AN, MD

2. WHY MONITORED?
• MEAN ARTERIAL PRESSURE- MAP: END POINT FOR RESUSCITATION.
• BIOLOGICAL MARKERS: MIXED VENOUS OXYGEN SATURATION (SVO2) AND
SERUM LACTATE.
• SYSTEMIC STROKE VOLUME AND CRDIAC OUTPUT?
• TECHNICAL DIFFICULTIES?
• MORE SUITABLE THAN MAP?
• EARLY WARNING OF CIRCULATION FAILURE?

3. FORMULA
CO= SV*HR

4. EVALUATE SV OR CO?
• ↓ STROKE VOLUME MAY BE COMPENSATED BY ↑ HEART RATE  “PSEUDO
NORMAL” CARDIAC OUTPUT.
• FLUID CHALLENGE ↑ STROKE VOLUME  ↓ HR CARDIAC OUTPUT NOT
CHANGE.
• PREFER DIRECT MEASUREMENT OF STROKE VOLUME

5. HOW?
STEP-BY-STEP PROCEDURE

6. OBTAIN A PARASTERNAL LONG-AXIS VIEW

7. MEASURE LEFT VENTRICULAR OUTFLOW
TRACT (LVOT) DIAMETER

8. APICAL FIVE-CHAMBER VIEW OF THE HEART.
RV: RIGHT VENTRICLE.
LV: LEFT VENTRICLE
AO: AORTA.
LA: LEFT ATRIUM
RA: RIGHT ATRIUM

9. PULSED-WAVE DOPPLER IN THE LVOT,
Width 2–4 mm in the LVOT
Just below the aortic valve

10. RECORD BLOOD FLOW VELOCITY
VTI OF LVOT
AORTIC VELOCITY TIME INTERVAL (VTI)

11. CALCULATE SV: SUMMARY
CO = SV * HR

12. STROKE VOLUME
MEASUREMENT AND THERAPEUTIC MANEUVER
• FLUID TEST.
• INOTROPES/VASODILATORS
• NITRIC OXIDE INHALATION.

13. CONCLUSIONS
• OFFER AN EASY WAY TO ASSESS STROKE VOLUME AND
CARDIAC OUTPUT.
• ASSESS THE BLOOD FLOW: SV
• HELPFUL IN ICU PRACTICE WHEN COMBINE WITH OTHER DATA