Related Experiment Video
Updated: Jun 3, 2026

Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge
Published on: January 20, 2023
Transient hemodynamic change and accuracy of arterial blood pressure-based cardiac output
Yoshifumi Kotake1, Takashige Yamada, Hiromasa Nagata
1Department of Anesthesiology, Keio University, Tokyo, Japan. ykotake@med.toho-u.ac.jp
Background:
The purpose of this study was to determine the effects of transient arterial blood pressure change on the accuracy of the FloTrac™/Vigileo™ monitor (Edwards Lifesciences, Irvine, CA).
Methods:
We compared stroke volume determined with the FloTrac/Vigileo with Doppler during anesthetic induction in 20 patients undergoing abdominal aortic reconstruction.
Results:
The difference between the FloTrac measurements of stroke volume and the Doppler measurements of stroke volume was -7.5 ± 20.5 mL (mean ± SD) before induction, 0.3 ± 14.9 before laryngoscopy, 17.5 ± 26.9 during laryngoscopy, 20.5 ± 27.6, and -4.5 ± 16.4 mL 3 minutes after endotracheal tube placement.
Conclusion:
The FloTrac/Vigileo measured stroke volume with reasonable accuracy during transient hypotension but overestimated stroke volume during transient hypertension.
Related Concept Videos
Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
Measurement of Blood Pressure
Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
Errors occurring during blood pressure monitoring
Several factors...
Equipments Used To Measure Blood Pressure
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...

