The Anatomic Structure of Pulmonary Arteries as a Source of Unreliability in Thermodilution Cardiac Output Measurement

Abstract

One of the most fundamental examination in intensive care medicine is cardiac output measurement, realized by pulmonary artery catherization. The thermodilution cardiac output estimation method is not resistant to various kinds of disturbances, which significantly decreases its sensitivity and specificity. The paper depicts investigations related to analysis of presumable new source of unreliability -asymmetric blood flow through pulmonary vessels. The investigations consisted of two phases: clinical examination (to obtain anatomical data) and computer modeling (to simulate the flow symmetry).

State of the Work Diagram of the Artificial Heart

“…In the case of heart problems caused by diseases, mechanical support is one of the methods of helping heart muscle recovery [1][2][3][4]. The main purpose of the ventricular assist device (VAD) is to aid the human circulatory system by introducing an external blood pump connected with the human vascular system.…”

The Possibility of a Simultaneous Transmission οf Ultrasound and Laser Radiation via Flexible Optical Silica Glass Fibre

“…The number of fringes can be used to calculate the displacement amplitude of an optical fibre (D). One fringe corresponds to half of the length of light wave [13][14][15][16][17]. Displacement amplitudes of the optical fibre were specified on the basis of the graphs presented in Fig.…”

Theoretical and model analysis of the unreliability of cardiac output measurement by means of the thermodilution method

“…Many papers [2,3,5,6,8,10,14,20,21] maintain, that iced thermodilution is more reliable than room temperature. In the presented work this thesis was confirmed theoretically (see Table 2) -relative sensitivity indices concerning the roomtemperature indicator are 3-10 times bigger than in the case of iced ones.…”

“…It is known, that the following components may influence the results obtained by the thermodilution method: spontaneous respiration [5,20], indicator injection rate [5,15] and hypothermia [14,15,20]. In the analysis the dynamic features of the thermistor were omitted.…”