Journal of clinical monitoring and computing
-
The pulmonary artery catheter (PAC) has been widely used for monitoring of critically ill patients over the years, but with advances in less invasive monitoring techniques, notably echocardiography, there are fewer indications for PAC insertion. Nevertheless, the PAC provides simultaneous monitoring of pulmonary artery pressures, cardiac filling, cardiac output and mixed venous oxygen saturation, and still has an important role in complex cases. Adequate and continued training are required to ensure that PAC-derived data are correctly interpreted and applied.
-
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.
-
One of the main goals of hemodynamic support is to preserve tissue perfusion. However issue perfusion is related more to microvascular perfusion than aortic blood flow. Monitoring the microcirculation has long been difficult. ⋯ Transcutaneous PCO2 measurement at ear lobe is particularly promising. Finally, near infrared spectroscopy can also provide interesting information, especially using vascular occlusion tests which reactivity of the microcirculation to a transient hypoxic insult. These different devices have provided important data helping us to better understand the pathophysiology of sepsis and multiple organ failure.
-
J Clin Monit Comput · Oct 2012
Radial-femoral concordance in time and frequency domain-based estimates of systemic arterial respiratory variation.
Commonly used arterial respiratory variation metrics are based on mathematical analysis of arterial waveforms in the time domain. Because the shape of the arterial waveform is dependent on the site at which it is measured, we hypothesized that analysis of the arterial waveform in the frequency domain might provide a relatively site-independent means of measuring arterial respiratory variation. Radial and femoral arterial blood pressures were measured in nineteen patients undergoing liver transplantation. ⋯ Assuming a PPV treatment threshold of 12 % (or equivalent), differences in treatment decisions based on radial or femoral estimates would arise in 12, 14, 5.4, 5.7, 4.8, and 5.5 % of minutes for SPV, PPV, AUCV, MAPV, spectral peak ratio, and spectral power ratio, respectively. As compared to frequency domain-based estimates of respiratory variation, SPV and PPV are relatively dependent on the anatomic site at which they are measured. Spectral peak and power ratios are relatively site-independent means of measuring respiratory variation, and may offer a useful alternative to time domain-based techniques.