Background: Haemodynamic monitoring of septic patients is impeded by the discrepancy between the macrohaemodynamics and the microcirculation of internal organs. Pulse contour analysis (PiCCO) provides new parameters for an improved assessment of the volume status of critically ill patients. However, changes in regional circulation, in particular those affecting the splanchnic perfusion, have proven to be especially important. The aim of our study was to compare macrohaemodynamic parameters (PiCCO) with microcirculation (OPS imaging) in severely septic patients with multiple organ failure.
Patients and methods: In seven patients suffering from septic shock and multiple organ failure (APACHE II score > 25) repeated examinations at a twenty-four hour interval were carried out by PiCCO monitoring and OPS imaging. OPS data were recorded for twenty seconds at 6 different buccal and sublingual localisations, adequately reflecting microvascular perfusion of the liver and the small intestine. Data were videotaped for off-line analysis, calculating current velocity in small and large venules (< 25 and > 25 microm), as well as functional capillary density.
Results: Significant correlations were found for current velocity in small venules with systemic vascular resistance (r(2) = 0.252, p < 0.05), mean arterial blood pressure (r(2) = 0.259, p < 0.05), and pH value (r(2) = 0.265, p < 0.05). In addition, a significant correlation was found between the oxygen transport index and the density of small vessels (r(2) = 0.355; p < 0.05).
Conclusion: According to our findings, data acquired through PiCCO monitoring may be used for a rough estimation of the microcirculation during severe sepsis and multiple organ failure. For an assessment of the local conditions of perfusion, however, there are limits in the use of the parameters that were the object of our research. For the measurement at localisations which are accessible non-invasively and representative of the splanchnic perfusion, OPS is the more accurate method for characterisation of the microcirculation, although a more extensive and time-consuming analysis is needed.