Cardiac output measured by electrical velocimetry in the CT suite correlates with coronary artery enhancement: a feasibility study.
Summary of "Cardiac output measured by electrical velocimetry in the CT suite correlates with coronary artery enhancement: a feasibility study."
Background: Cardiac output (CO) is inversely related to vascular contrast medium (CM) enhancement during computed tomography (CT). Impedance cardiography with a new technique, electrical velocimetry (EV), may create opportunities to measure CO pre-examination for adaptation of CM injection parameters. Purpose: To relate CO(EV) measured by radiology staff to aortic attenuation as a measure of coronary artery attenuation during CT coronary angiography (CTCA), and to formulate a tentative statistical model to adapt CM injection parameters to CO. Material and Methods: CO(EV) was measured immediately before 100 kVp CTCA (64-multirow detector) in 27 patients with presumed coronary artery disease. For CTCA, 260 mg I/kg (maximum dosage weight: 80/90 kg for women/men) was injected intravenously during 12 s. Simple linear regression analysis was performed to explore the correlation between aortic attenuation (Hounsfield units, HU) and body weight, the influence of CO(EV) on aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s), and to establish a tentative formula on how to adapt CM injection parameters to CO(EV) and desired aortic attenuation. Results: The correlation between aortic attenuation and body weight was weak and non-significant (r=-0.14 after outlier exclusion). A significant negative correlation (r=-0.63) was found between aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s) and CO(EV). The resulting formula, CM dose rate=CO(EV)x(aortic attenuation-240)/55, made it possible to calculate CM volumes and injection rates at various COs and, for example, the present mean aortic attenuation (438 HU), injection time (12 s), CM concentration (320 mg I/ml), and a certain body weight. Conclusion: EV makes it possible to measure CO in the CT suite before vascular examinations. Hence, CM doses may be decreased in low CO states to reduce the risk of CM-induced nephropathy without jeopardizing diagnostic quality and may be increased in high CO states to avoid poor enhancement.
Department of Radiology, Sahlgrenska University Hospital and Sahlgrenska Academy at Gothenburg University.
This article was published in the following journal.
Name: Acta radiologica (Stockholm, Sweden : 1987)
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20715894
- DOI: http://dx.doi.org/10.3109/02841851.2010.503663
Medical and Biotech [MESH] Definitions
Cardiac Output, High
A state of elevated cardiac output due to conditions of either increased hemodynamic demand or reduced cardiac oxygen output. These conditions may include ANEMIA; ARTERIOVENOUS FISTULA; THYROTOXICOSIS; PREGNANCY; EXERCISE; FEVER; and ANOXIA. In time, compensatory changes of the heart can lead to pathological form of high cardiac output and eventual HEART FAILURE.
Cardiac Output, Low
A state of subnormal or depressed cardiac output at rest or during stress. It is a characteristic of CARDIOVASCULAR DISEASES, including congenital, valvular, rheumatic, hypertensive, coronary, and cardiomyopathic. The serious form of low cardiac output is characterized by marked reduction in STROKE VOLUME, and systemic vasoconstriction resulting in cold, pale, and sometimes cyanotic extremities.
A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
Graphic registration of the heart sounds picked up as vibrations and transformed by a piezoelectric crystal microphone into a varying electrical output according to the stresses imposed by the sound waves. The electrical output is amplified by a stethograph amplifier and recorded by a device incorporated into the electrocardiograph or by a multichannel recording machine.
A condition of fainting spells caused by heart block, often an atrioventricular block, that leads to BRADYCARDIA and drop in CARDIAC OUTPUT. When the cardiac output becomes too low, the patient faints (SYNCOPE). In some cases, the syncope attacks are transient and in others cases repetitive and persistent.
Electrical velocimetry (EV) is a non-invasive method of continuous left cardiac output monitoring based on measurement of thoracic electrical bioimpedance. The objective was to validate EV by investig...
BACKGROUND: When assessing the function of the cardiovascular system, cardiac output (CO) is a substantial parameter. For its determination, numerous non-invasive techniques have been proposed in the...
PURPOSE: Cardiac output (CO), the product of stroke volume (SV) and heart rate, is essential to guarantee organ perfusion, especially in the intensive care setting. As invasive measurement of CO bears...
Bioreactance is a novel non-invasive method for cardiac output measurement that involves the analysis of blood flow-dependent changes in the phase shifts of electrical currents applied across the ches...
OBJECTIVE: To assess the combination of a non-invasive blood oxygen content (CaO(2)) monitor and a non-invasive cardiac output (CO) monitor to continuously measure oxygen delivery (DO(2); DO(2) = Ca...
The cardiac output (CO) is an important parameter in the diagnosis and therapy of cardiac diseases. The current standard methods for the determination of the CO, however, are either invasi...
To assess whether a non-invasive cardiac output monitor can follow heart function in children during treatments in the hospital. To establish a normal reference for children who are well...
Cardiac output, the amount of blood pumped by the heart in one minute, will be measured in pediatric patients undergoing surgery involving cardiopulmonary bypass (CPB). Cardiac output will...
Accurate cardiac output determination is a commonly used and important index of myocardial performance. The thermodilution method using a pulmonary artery catheter is the most common appro...
The purpose of this study is to evaluate a new monitor that measures cardiac output (amount of blood pumped by the heart). The system that is being tested in this study, called Endotrachea...