Continuous Monitoring of Cardiac Output and Left Atrial Pressure
Cardiac output (CO) is the volume of blood ejected by the heart per unit time, while left atrial pressure (LAP) is the blood pressure in the left heart during the cardiac filling phase. Both CO and LAP permit the diagnosis of various cardiovascular disease processes and thereby facilitate imminent therapeutic decisions. Thus, the ability to monitor effectively CO and LAP is extremely desirable. Several conventional methods exist to measure CO and LAP. However, they are generally too invasive and unsafe, too impractical and/or too inaccurate for clinical use.
Description of Technology
This invention provides a method and apparatus for continuous and automatic monitoring of CO and LAP by mathematical analysis of either a pulmonary artery pressure (PAP) waveform, or a right ventricular pressure (RVP) waveform. These waveforms may be measured accurately via pulmonary artery catheterization, which is frequently performed in intensive care units and operating and recovery rooms, as well as by using existing implantable device technology. The resulting blood pressure waveforms are used to calculate a personalized circulatory system for a given patient by fitting a general circulatory model to the waveforms to obtain a personalized circulatory model, and from that model, to calculate predicted CO and LAP waveforms. The invention is superior to existing clinical methods, as it permits continuous and accurate monitoring of both CO and LAP. Moreover, in contrast to the clinical and conventional methods, the invention may be used with existing implantable devices, allowing ambulatory monitoring of CO and LAP. A prototype system was constructed and successfully tested.
- Increased prediction accuracy: Made possible by the superior mathematical analysis tool in software form.
- Personalized circulatory systems: Ability to construct personalized circulatory systems for individual patients, with improved prediction accuracy and usefulness as a diagnostic and treatment tool.
- Real time predictions: Ability to generate the above predicted blood pressure and blood flow values in real time, on a continuous basis, and automatically.
- Lack of competing technologies: No other technology is able to generate CO and LAP predictions on a continuous basis, so this technology has no real competitors at present.
- Safety and versatility of use: Existing implantable device technology can be used to allow ambulatory monitoring of CO and LAP.
- Low cost: The invention is primarily a mathematical analysis tool put into software. The rest of the invention uses existing medical technology.
- Non-invasive improvements: In the future, non-invasive blood pressure readings may allow the determination of the PAP and/or RVP waveforms used as inputs in this invention for predicting CO and LAP.
Continuous monitoring of CO and LAP in ICUs, and use in conjunction with implantable devices for ambulatory patients.
US 2007/0197921 A1 (filed Feb 21, 2006)
Ramakrishna Mukkamala, Richard Cohen