Measurement of central blood volume by external monitoring.
نویسندگان
چکیده
W ITH EXTENSIVE application of the Hamilton-Stewart dj'e-dilution technique for measurement of central blood volume (CBV), it has become apparent that the method may be insensitive to small but significant changes in volume. Reasons for this, presumably, rest with the rather large volume measured and the inherent errors of the technique. 1 Using a peripheral vein injection , the volume measured may be as high as 60 per cent of the total blood volume. 2 Only by using pulmonary-artery injection can it be reduced to 20 per cent of total blood volume. 3 It would appear that, with these large volumes , small but significant changes (on the order of 100 to 200 cc.) could occur in various disease states or acute situations without being detected. 1 ' 3 Use of radioactive materials and external monitoring appears to offer a method for measuring just the blood in the heart and lungs without the need for cardiac catheteri-zation. By the use of a sensitive counter over the precordium and a gamma-emitting isotope , separate peaks for right and left ventric-ular filling can be measured. The difference in time between the two peaks multiplied by the cardiac output gives a measure of pulmonary blood volume (PBV). Although the initial work with this technique was done by Prinzmetal in 1949, 4 the central blood volume has not been studied in a large series of normal subjects. This investigation was under-taken to evaluate the technique in such a series. Methods Hospitalized ambulatory patients without evidence of cardiovascular disease were used in the study, the majority coming from the general medical wards of a Veterans Administration Hospital. A total of 39 patients is repoi-ted. The external counter used was a DS 5-1 Nuclear Chicago probe, with a one-inch thallium-activated sodium iodide crystal. This was used with three different combinations of collimation and counter placement. In all eases, the counter was placed over the precordium under fluoroscopie control. The output from the counter was fed into a radiation analyzer using a five-volt window. This output, in turn, was fed into a binary sealer which had been modified to record four counts, or multiples thereof, as a deflection ("blip") on an oscillographie tracing. Both an electrocardio-gram and an injection marker were recorded simultaneously on the tracing. The results were discarded when obvious variation in the heart rate during this measurement indicated an unsteady state. The oscillographie tracings …
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ورودعنوان ژورنال:
- Circulation research
دوره 9 شماره
صفحات -
تاریخ انتشار 1961