Search results for "Cardiac"
showing 10 items of 1495 documents
Continuous measurement of cardiac output by the Fick principle in infants and children: comparison with the thermodilution method.
1996
To compare a system that continuously monitors cardiac output by the Fick principle with measurements by the thermodilution technique in pediatric patients.Prospective direct comparison of the above two techniques.Pediatric intensive care unit of a university hospital.25 infants and children, aged 1 week to 17 years (median 10 months), who had undergone open heart surgery were studied. Only patients without an endotracheal tube leak and without a residual shunt were included.The system based on the Fick principle uses measurements of oxygen consumption taken by a metabolic monitor and of arterial and mixed venous oxygen saturation taken by pulse- and fiberoptic oximetry to calculate cardiac…
An integrated approach based on uniform quantization for the evaluation of complexity of short-term heart period variability: Application to 24 h Hol…
2007
We propose an integrated approach based on uniform quantization over a small number of levels for the evaluation and characterization of complexity of a process. This approach integrates information-domain analysis based on entropy rate, local nonlinear prediction, and pattern classification based on symbolic analysis. Normalized and non-normalized indexes quantifying complexity over short data sequences (â¼300 samples) are derived. This approach provides a rule for deciding the optimal length of the patterns that may be worth considering and some suggestions about possible strategies to group patterns into a smaller number of families. The approach is applied to 24 h Holter recordings of …
Evaluation of Hemodynamic Parameters for Adaptive Control of the Artificial Heart by Simulation of the Vascular System
1984
Abstract A nonlinear dynamic mathematical model of the cardiovascular system is outlined, which is employable to analyse the hemodynamic system behaviour under normal as well as under pathological conditions. By modifying this model, assuming that cardiac output is constant at a preset level (which is in accordance with most of the total artificial heart systems, since their pumps output is preselected with fixed driving parameters), the hemodynamic behaviour of a circulation system with an artificial heart was simulated. Comparing the simulation results with those obtained from total artificial heart experiments, a good agreement in right atrial and aortic pressure under exercise condition…
Hemodynamic Parameters Change Earlier Than Tissue Oxygen Tension in Hemorrhage
2010
BACKGROUND: Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS: Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after p…
Pulmonary haemodynamics in obstructive sleep apnoea.
1995
In patients with obstructive sleep apnoea syndrome (OSAS), pulmonary haemodynamics can show both transient perturbations during sleep and permanent alterations. During sleep, repeated fluctuations in pulmonary artery pressure and pulmonary wedge pressure, coincident with apnoeas, can be observed. Calculation of transmural pressure values is preferable to intravascular pressures in OSAS, due to the marked swings in intrathoracic pressure associated with obstructive apnoeas. Pulmonary artery pressure may progressively increase during sleep, particularly in close sequences of highly desaturating apnoeas. Apnoea-induced hypoxia appears as the most important determinant of this pulmonary artery …
Cardiac output following fetoscopic coagulation of major placental vessels in fetal sheep.
2008
Objectives To measure changes in cardiac output (CO) after partial cord occlusion in fetal sheep in order to investigate pathophysiological fetal adaptation mechanisms in a simulated acute placental insufficiency model under standardized conditions, with the aim of finding relevant methods for monitoring human fetuses during stress situations. Methods We used minimally invasive, percutaneous endoscopic techniques to close umbilical vessels in mid-gestational fetal sheep. Placental blood flow was reduced by preferentially closing first arterial and then the concomitant venous umbilical vessels within a short time interval. The investigations were carried out on 11 pregnant ewes at a median g…
In vitro cardiac performance in the sub-antarctic notothenioids Eleginops maclovinus (subfamily eleginopinae), Paranotothenia magellanica, and Patago…
1997
There is lack of information concerning species diversification in the Non-Antarctic Nototheniid fish both in relation with their variation in organismal performance and in the morphofunctional characteristics underlying this variation. This work was designed to study in three Sub-Antarctic Nototheniids, Eleginops maclovinus, Patagonotothen tessellata, and Paranotothenia magellanica, cardiocirculatory features that may reflect interspecific differences in organismal performance, which in rum may explain aspects of evolutionary and ecological diversity. Haematocrit values were similar in all three species (between 28 and 3?), being in the range of that observed in other red-blooded Nototheni…
Structural and Mechanical Characteristics of the Heart of the Icefish Chionodraco hamatus (Lönnberg)
1991
The absence of haemoglobin from the blood of icefish, antarctic teleosts of the family Chaenichthydae, has stimulated important physiological mechanisms which serve to compensate for the absence of the respiratory pigment. In view of the central role played by the circulation in meeting the oxygen demands of the tissues, it is not surprising to find that the cardiocirculatory system has been extensively remodelled in icefish. These adaptations include: (1) increases in blood volume, from two to four times larger than that in many teleosts (Hemmingsen and Douglas 1970; Holeton 1970); (2) increases in blood flow associated with lowered oxygen demands (Hemmingsen and Douglas 1970; Holeton 1970…
Comparison between doppler-echocardiography and uncalibrated pulse contour method for cardiac output measurement. a multicenter observational study
2016
Objectives: Echocardiography and pulse contour methods allow, respectively, noninvasive and less invasive cardiac output estimation. The aim of the present study was to compare Doppler echocardiography with the pulse contour method MostCare for cardiac output estimation in a large and nonselected critically ill population. Design: A prospective multicenter observational comparison study. Setting: The study was conducted in 15 European medicosurgical ICUs. Patients: We assessed cardiac output in 400 patients in whom an echocardiographic evaluation was performed as a routine need or for cardiocirculatory assessment. Interventions: None. Measurements and Main Results: One echocardiographic car…
Ultrasonography in Heart Failure: A Story that Matters
2019
Abstract Heart failure (HF) is a clinical syndrome caused by structural and/or functional cardiac abnormalities, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress. It is the leading cause of hospitalization in Internal Medicine departments. This article aims at reviewing evidence of the importance of ultrasound in HF both for hospitalized patients and in the follow-up. Ultrasound may be used as a recovery monitoring instrument at the bedside and also as a global cardiovascular assessment tool for these patients. HF represents an exciting opportunity to create an integrative ultrasound approach in Internal Medicine and/or Geriatric departme…