Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2012
Combination of continuous pulse pressure variation monitoring and cardiac filling pressure to predict fluid responsiveness.
To assess if combining central venous pressure (CVP) and/or pulmonary capillary wedge pressure (PCWP) information with arterial pulse pressure variation can increase the ability to predict fluid responsiveness in patients under general anesthesia. This study is a retrospective analysis of patients scheduled for coronary artery bypass surgery and monitored with a pulmonary artery catheter who underwent a volume expansion after induction of general anesthesia. Among the 46 patients studied, 31 were responders to volume expansion. ⋯ Combining information on right and/or left cardiac filling pressures with PPV did not increase the ability to predict whether a patient will be a responder or a non-responder to volume expansion. The ability to identify a potentially fluid responsive patient was no better using PPV plus cardiac filling pressures when compared to using PPV alone. Therefore, if PPV values are being monitored in a patient, CVP and PCWP values do not provide additional information to predict fluid responsiveness.
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J Clin Monit Comput · Oct 2012
ReviewHemodynamic management of cardiovascular failure by using PCO(2) venous-arterial difference.
The difference between mixed venous blood carbon dioxide tension (PvCO(2)) and arterial carbon dioxide tension (PaCO(2)), called ∆PCO(2) has been proposed to better characterize the hemodynamic status. It depends on the global carbon dioxide (CO(2)) production, on cardiac output and on the complex relation between CO(2) tension and CO(2) content. ⋯ The difference between central venous CO(2) tension and arterial CO(2) tension, which is easy to obtain can substitute for ∆PCO(2) to assess the adequacy of cardiac output. Differences between local tissue CO(2) tension and arterial CO(2) tension can also be obtained and provide data on the adequacy of local blood flow to the local metabolic conditions.
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The transpulmonary thermodilution technique (TPTD) is a safe, multi-parametric advanced cardiopulmonary monitoring technique that provides important parameters required for making decisions in critically ill patients. The TPTD provides more reliable indicators of preload than filling pressures, the unique measurement of extravascular lung water (EVLW) and comparable accuracy in measuring cardiac output (CO). Intermittent measurement of the CO by TPTD when coupled with pulse contour analysis, offer automatic calibration of continuous CO, as well as accurate assessment of volumetric preload, fluid responsiveness and EVLW. TPTD-guided algorithms have been shown to improve the management of high-risk surgical and critically ill patients.
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Recent advance in imaging modalities used frequently in clinical routine can provide description of the geometrical and hemodynamical properties of the arterial tree in great detail. The combination of such information with models of blood flow of the arterial tree can provide further information, such as details in pressure and flow waves or details in the local flow field. Such knowledge maybe be critical in understanding the development or state of arterial disease and can help clinicians perform better diagnosis or plan better treatments. ⋯ Our development of a generic and patient-specific model of the human arterial tree permitting to study pressure and flow waves propagation in patients is presented. The predicted pressure and flow waveforms are in good agreement with the in vivo measurements. We discuss the utility of these models in different clinical application and future development of interest.