lithium-chloride and Cardiac-Output--High

The LiDCO plus system is a minimally/non-invasive technique of continuous cardiac output measurement. In common with all cardiac output monitors this technology has both strengths and weaknesses. This review discusses the technological basis of the device and its clinical application.

Topics: Cardiac Output; Cardiac Output, High; Cardiac Output, Low; Humans; Indicator Dilution Techniques; Lithium Chloride; Monitoring, Intraoperative; Monitoring, Physiologic; Technology Assessment, Biomedical; Thermodilution

Lithium dilution cardiac output (LiDCO trade mark; LiDCO, London, UK) is a minimally invasive indicator dilution technique for the measurement of cardiac output. It was primarily developed as a simple calibration for the PulseCO trade mark (LiDCO, London, UK) continuous arterial waveform analysis monitor. The technique is quick and simple, requiring only an arterial line and central or peripheral venous access. These lines would probably already have been inserted in critical care patients. A small dose of lithium chloride is injected as an intravenous bolus, and cardiac output is derived from the dilution curve generated by a lithium-sensitive electrode attached to the arterial line. Studies in humans and animals have shown good agreement compared with results obtained with other techniques, and the efficacy of LiDCO trade mark in pediatric patients has also been proven. Compared with thermodilution, lithium dilution showed closer agreement in clinical studies with electromagnetic flow measurement.PulseCO trade mark is a beat-to-beat cardiac output monitor that calculates stroke volume from the arterial pressure waveform using an autocorrelation algorithm. The algorithm is not dependent on waveform morphology, but, rather, it calculates nominal stroke volume from a pressure-volume transform of the entire waveform. The nominal stroke volume is converted to actual stroke volume by calibration of the algorithm with LiDCO trade mark. Initial studies indicate good fidelity, and the results from centers in the United States and the United Kingdom are extremely encouraging. The PulseCO trade mark monitor incorporates software for interpretation of the hemodynamic data generated and provides a real-time analysis of arterial pressure variations (ie, stroke volume variation, pulse pressure variation, and systolic pressure variation) as theoretical guides to intravascular and cardiac filling.

Topics: Adult; Animals; Cardiac Output; Cardiac Output, High; Cardiac Output, Low; Child, Preschool; Critical Care; Dose-Response Relationship, Drug; Extracorporeal Membrane Oxygenation; Female; Horses; Humans; Indicator Dilution Techniques; Injections, Intravenous; Lithium Chloride; Male; Monitoring, Physiologic; Sensitivity and Specificity; Thermodilution

Lithium dilution cardiac output by LiDCOplus (LiDCO, Cambridge, UK) is a validated methodology for measuring cardiac output. It is used to calibrate a pulse pressure analysis algorithm (PulseCO) for the continuous measurement of subsequent changes in this variable. The variability of measurements, or precision, within patients of lithium dilution cardiac output has not previously been described.. Thirty-five hemodynamically stable patients in intensive care, with no significant variability in heart rate, mean arterial pressure or central venous pressure, were recruited. Fifty-three determinations of cardiac output were made, each using four lithium dilution measurement curves performed consecutively within a maximum period of 10 min. The coefficient of variation of the measurements was determined and used to derive the least significant change in cardiac output that this technique could reliably detect.. For a single measurement, the coefficient of variation was 8%. This equates to the technique being able to detect a change (least significant change) between two measurements of 24%. Averaging two lithium dilution measurements improved the coefficient of variation to 6% with a least significant change of 17%. Using the average of three curves reduced the coefficient of variation to 5% with a least significant change of 14%.. To achieve a good precision with this technique, three lithium dilution measurements should be averaged. This will allow changes in cardiac output of more than 14% to be reliably detected. The understanding of the precision of this technique allows the user to know when a real change has happened to their patient.

Topics: Aged; Cardiac Output, High; Cardiac Output, Low; Critical Care; Dose-Response Relationship, Drug; Female; Hemodynamics; Humans; Indicator Dilution Techniques; Injections, Intravenous; Intensive Care Units; Lithium Chloride; Male; Middle Aged; Models, Biological; Monitoring, Physiologic; Sensitivity and Specificity; Thermodilution