[Method of continuous monitoring of stroke and minute cardiac volume by the aortic pressure curve].
A new method of determining the cardiac output and stroke volume on the basis of the aortic pressure curve by way of a direct pressure-volume calibration is suggested. For this purpose two catheters are introduced into the ascending aorta, and via one of them saline is supplied with a constant volume rate (delta V). At the same time the augmentation of the diastolic pressure in the aorta (delta P) caused by the administration of the saline is recorded by means of the second catheter which tip is located some 3--4 cm below the first one along the blood flow. The mean pulse pressure in the aorta (Pp) also corresponds to a definite flow in the aorta (V). The relationship between the volume and pressure in the aorta within the physiological range is a lineal function. Hence, V = Pp-delta V divided by delta P cm3/sec. By multiplying this value times the duration of the cardiac cycle in seconds, the stroke volume is obtained. By dividing the volume of the administered saline (delta V.t) into the pressure augmentation area (delta S), the volume corresponding to each unit of the pressure area is found. Then by multiplying this calibration value times the area under the pressure curve in any cardiac cycle (S) again the stroke volume is obtained: Vstr = S-deltaV-t divided by delta S cm3. By a continuous recording of the mean pulse pressure in the aorta and of the full pressure curve it is possible to conduct a continuous control of the stroke volume and cardiac output using the preliminarily obtained calibration value. The suggested method permits to determine the filling of the aorta below the coarctation, the blood return from the aorta into the left ventricle in cases of aortic insufficiency, as well as the elastic properties of the aorta. An attempt was made to substitute the recording of the volume pulse and left arm rheopletysmography for the recording catheter.
D001011:Aorta / Q000502:physiology*; D001017:Aortic Coarctation / Q000503:physiopathology; D001018:Aortic Diseases / Q000503:physiopathology; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods; D002302:Cardiac Output; D002306:Cardiac Volume; D006334:Heart Function Tests / Q000379:methods; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007680:Kidney Neoplasms / Q000503:physiopathology; D008944:Mitral Valve Insufficiency / Q000503:physiopathology; D008946:Mitral Valve Stenosis / Q000503:physiopathology
Metod nepreryvnogo kontrolia za udarnym i minutnym ob'emami serdtsa po kryvoĭ davleniia v aorte