The International journal of artificial organs
-
We studied in 13 hemodialysis patients intradialytic variations of blood volume (BV) and cardiac output, by means of non-invasive methods. We found a weak correlation, r 0.2 or less, between BV variations and intradialysis blood pressure variations. The sensitivity of the former in describing the variations of the latter was only 32%. ⋯ On the contrary, the correlation between percent variations of cardiac output index and MAP was 0.68 with a sensitivity and specificity of 90% and 59%, respectively. Unfortunately these promising results were obtained only with an estimate of cardiac output obtained by echocardiography and not by transthoracic impedance cardiography, which is much more feasible than the former as on-line monitoring of cardiac output. On-line monitoring of hemodynamic parameters is an appealing but still unsolved task.
-
Comparative Study
Can the artificial heart make the circulation become fractal?
In order to analyze the hemodynamic parameters in prosthetic circulation as an entity and not as decomposed parts, non linear mathematical analyzing techniques, including the fractal dimension analyzing theory, were utilized. Two pneumatically actuated ventricular assist devices were implanted, as biventricular bypasses (BVB), in chronic animal experiments, using four healthy adult goats. For the comparison between the natural and prosthetic circulation in the same animals, the BVB type complete prosthetic circulation model with ventricular fibrillation, was adopted. ⋯ By the use of the Box counting method, fractal dimension analysis of the hemodynamics was performed. Return map of the hemodynamics during natural and artificial circulation showed fractal characteristics, and fractal dimension analysis of the arterial blood pressure revealed the fact that lower dimensional fractal dynamics were evident during prosthetic circulation. Fractal time series data is suggested to have robustness and error resistance, thus our results suggest that the circulatory regulatory system with an artificial heart may have these desired characteristics.
-
Clinical Trial Controlled Clinical Trial
Uncomplicated central vein catheterization of high risk patients with real time ultrasound guidance.
Internal jugular vein cannulation has become a routine and clinically important aspect of medical care of critically ill patients. The landmark guided technique usually affords rapid and easy vascular access, but is not always successful and may be complicated by arterial puncture, hematoma, or pneumothorax. Some categories of patients, in particular patients with no external landmarks and patients with coagulopathies, appear to be at an increased risk of complications. ⋯ In particular the 13 cannulations performed in 12 high risk patients were all successful at the first attempt, with no complications. In the overall population successful cannulations improved from 80% to 100%, first attempt success from 20% to 87% and carotid punctures decreased from 33% to 3.2%. Our results confirm that ultrasound guided cannulation of the internal jugular vein allows safer operation in high risk patients or when access problems are anticipated.
-
Clinical Trial Controlled Clinical Trial
The outcome of critically ill elderly patients with severe acute renal failure treated by continuous hemodiafiltration.
To study the outcome of critically ill elderly patients with severe acute renal failure managed by continuous hemodiafiltration. ⋯ A greater than 40% survival was achieved in critically ill elderly patients with severe acute renal failure by the use of continuous hemodiafiltration. These patients had an in hospital survival comparable to that of younger patients. These findings support an aggressive renal replacement approach in such patients and suggest that continuous hemodiafiltration may be ideally suited to their management.