Surgery – Truss – Pad
Patent
1988-12-22
1991-04-23
Howell, Kyle L.
Surgery
Truss
Pad
128692, 128736, A61B 502
Patent
active
050092340
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to catheter systems for monitoring the condition of a patient's heart, and more particularly it relates to such catheter systems operable with the thermodilution method of determining cardiac output.
BACKGROUND OF THE INVENTION
Catheters to be introduced into the human body have been known for many years. The first description of such a catheter for probing the heart is from W. Forssmann and appeared in Klinische Wochenschrift 8, 1929, pp. 2085 ff. A great variety of experience has been gathered with such catheters in the area of diagnostics. A survey of the catheters used and the diagnostic measures to be performed therewith can be found in the company publication Hewlett-Packard Application Note 762 "A Guide to Hemodynamic Monitoring using the Swan-Ganz Catheter", 1978. As of the seventies, catheters with so-called dilatation balloons have also been used. Such balloons are inflatable from the outside and serve to widen congenital or acquired narrowings (stenoses) in the human vascular system. See for example A. Cribier et al., "Percutaneous Transluminal Balloon Valvuloplasty of Adult Aortic Stenosis": Report of 92 cases, published in JACC Vol., No. 2, Feb. 1987, pp. 381 ff.
One diagnostic measure, for example, is to take hydrostatic pressure measurements with one catheter having a plurality of separate channels and a plurality of lumina, a so-called multilumen catheter. The individual channels are directed toward the exatracorporal proximal end of the catheter and may be connected via standardized connections to pressure sensors for measuring the hydrostatic pressures at the lumen openings of the individual channels and the pressure difference or pressure gradient. Such a catheter may also be provided additionally with a temperature sensor, e.g. a small thermistor, for taking measurements of the cardiac pumping behavior, i.e. measurements of the cardiac output, by a so-called thermodilution method. By this method, according to the prior art, a cryogen solution is injected from the proximal end of the catheter via a channel into the blood vessel, e.g. the right ventricle of the heart, which solution after a certain time flows past the temperature sensor located toward the distal end. The temperature drop at the temperature sensor location as a function of the flow time of the cryogen solution in the blood circulation can then be used to determine the cardiac output, as set forth for example in U. S. Pat. Nos. 4,502,488 and 4,105,022. The connections of the temperature sensor are directed in the catheter tube to the proximal end and are connected there via standardized connections with a microcomputer, which directly states the required measured values, such as the cardiac output in liters per minute. Such measurements up to now have been taken primarily only in the right heart, with the catheter being pushed through a vein into the right heart or the pulmonary circulation.
A typical case of routine application of such a right heart and pulmonary cardiac output measuring catheter is with a patient having a previous myocardial infarction or some type of cardiomyopathy and therefore reduced pumping function of the heart. In such a patient a typical procedure is to apply a left ventricular angiography catheter and to inject dye into the left ventricle and by means of X rays to determine the contraction pattern of this left ventricle. It is described as ejection fraction indicating how much of the percentage of the ventricular volume is ejected by one heart beat. In addition to this indicator of the overall ventricular function, routinely now a second catheter is put into the venous and right heart system of the patient in order to measure cardiac output by the conventional way described above to thereby determine the overall pumping function of the heart in liters of blood pumped per minute. Of special interest also is the knowledge of cardiac output in diagnosing the degree of severeness of valvular stenosis or regurgitation. The prior art required the use of
REFERENCES:
patent: 3446073 (1969-05-01), Auphan et al.
patent: 3726269 (1973-04-01), Webster, Jr.
patent: 3733899 (1973-05-01), Auphan et al.
patent: 4508103 (1985-04-01), Calisi
patent: 4543961 (1985-10-01), Brown
patent: 4587975 (1986-05-01), Salo et al.
patent: 4595015 (1986-06-01), Jansen et al.
patent: 4621646 (1986-11-01), Bryant
patent: 4632125 (1986-12-01), Webler et al.
patent: 4718423 (1988-01-01), Willis et al.
patent: 4730623 (1988-03-01), Lee
patent: 4777951 (1988-10-01), Cribier et al.
patent: 4796640 (1989-01-01), Webler
Michael J. Ackerman, Ph.D., Computer Applications in Medical Care, Nov. 10-Nov. 13, Baltimore, pp. 41-44.
Brown Laurence R.
Howell Kyle L.
Lacyk John P.
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