Simple and safe bedside method for serial measurement of left ventricular ejection fraction, cardiac output, and pulmonary blood volume.

Abstract

A simple, safe method for bedside measurement of left ventricular function and pulmonary blood volume has been developed. A single scintillation probe positioned over the mid-left ventricle records the passage of bolus of radionuclide (ll3mIn) injected into the superior vena cava, from which the left ventricular ejection fraction can be determined after proper background correction. ll3mIn, half-life I-7 hours, easily prepared from a commercially available generator, rapidly binds to plasma transferrin and can be used to determine blood volume and cardiac output. With cardiac output and left ventricular ejection fraction determined simultaneously, left ventricular end-diastolic volume can be calculated and pulmonary blood volume can be determined from pulmonary transit time and cardiac output.With this method, we have demonstrated stable and changing left ventricular function and pulmonary blood volume in a variety of clinical situations, e.g. myocardial infarction, pulmonary embolism, and severe pulmonary parenchymal disease. Blood volume and cardiac output so determined correlate well with standard techniques. The left ventricular ejection fraction determined by this method correlates well with this measurement obtained from left ventricular angiography. Loss of the pulmonary valley between the right and left ventricles has been demonstrated in severe pulmonary vascular obstruction (embolism), in severe bronchial obstruction, and as a result of massive right ventricular dilatation in the presence of normal pulmonary blood volume. This method, which can be frequently performed, has proved useful in serial evaluation of cardiac function at the bedside.The ability to quantitate left ventricular function at the bedside would be an important aid for the care of the seriously ill patient, especially if the measurement could be repeated frequently. Not only would such information be of value in the management of the individual patient, but it would provide the basis for evaluation of various forms of therapy. External monitoring of the passage of a bolus of radioactive tracer through the central circulation has been developed over the past 25 years (Prinzmetal et al., 1948) in an attempt to fulfil the need for a safe, easily repeatable method of quantitating cardiac function. Earlier attempts to use simple scintillation probes and low frequency data for evaluation of the left ventricle after a right-sided

Measurement of absolute left ventricular volume from gated blood pool studies.

“…A 5-ml test tube containing 15 IACi of technetium-99m in 3 ml of water and a pear-shaped, 100-ml flask containing 375 MCi of technetium-99m in 75 ml of water were suspended from the ceiling. The count rates from these two sources were determined with the same collimator/camera system used in the volume study, at collimator-to-source distances of 2-16 cm.…”

Repetitive Real-Time Acquisition of Pressure-Volume Loops Using the Nuclear Probe – A New Technique for Interventional Studies

“…The nuclear probe is a single crystal nuclear detector which provides accurate measures of relative left ventricular volume and ejection fraction (EF) [5][6][7][8][9][10][11][12][13]. Pre vious studies have demonstrated a very good correlation between EF measured with the nuclear probe and nuclear angiography.…”

Assessment of left ventricular performance and myocardial viability using quantitative radioisotope techniques.

“…Using the first pass method, ejection fraction can be determined with an accuracy comparable with contrast angiocardiographic techniques (Ashburn et al, 1972;Steele et al, 1974). In order to obtain diagnostic information, sufficiently high count rates and a time resolution of at least 50 milliseconds per frame are necessary (Schad, 1977).…”