Lung assist devices influence cardio-energetic parameters: Numerical simulation study.

We aim at an analysis of the effects mechanical ventilators (MVs) and thoracic artificial lungs (TALs) will have on the cardiovascular system, especially on important quantities, such as left and right ventricular external work (EW), pressure-volume area (PVA) and cardiac mechanical efficiency (CME). Our analyses are based on simulation studies which were carried out by using our CARDIOSIM(©) software simulator. At first, we carried out simulation studies of patients undergoing mechanical ventilation (MV) without a thoracic artificial lung (TAL). Subsequently, we conducted simulation studies of patients who had been provided with a TAL, but did not undergo MV. We aimed at describing the patient's physiological characteristics and their variations with time, such as EW, PVA, CME, cardiac output (CO) and mean pulmonary arterial/venous pressure (PAP/PVP). We were starting with a simulation run under well-defined initial conditions which was followed by simulation runs for a wide range of mean intrathoracic pressure settings. Our simulations of MV without TAL showed that for mean intrathoracic pressure settings from negative (-4 mmHg) to positive (+5 mmHg) values, the left and right ventricular EW and PVA, right ventricular CME and CO decreased, whereas left ventricular CME and the PAP increased. The simulation studies of patients with a TAL, comprised all the usual TAL arrangements, viz. configurations "in series" and in parallel with the natural lung and, moreover, hybrid configurations. The main objective of the simulation studies was, as before, the assessment of the hemodynamic response to the application of a TAL. We could for instance show that, in case of an "in series" configuration, a reduction (an increase) in left (right) ventricular EW and PVA values occurred, whereas the best performance in terms of CO can be achieved in the case of an in parallel configuration.

Telecar: an Italian telecardiology project.

The Telecar (tele-assistance cardiology) project was an example of tele-assistance between health centres of the Regione Lazio in Italy. The project was approved by the Ministry of Health, financed with 500,000,000 lire and carried out by an operative station within 'La Sapienza' University (Rome). About 40 of the health centres in Lazio that did not have cardiologists or electrocardiography (ECG) equipment were provided with telematic instruments (Cardiophone and fax). With this equipment, they were able to transmit ECG signals and receive copies of ECG reports. The 40 health centres included first-aid clinics, 'guardia medica' surgeries and community centres. The project was carried out between 1989 and 1992. During these three years the health centres transmitted a total of 4807 ECGs, 2057 (43%) of which were routine, the remaining 2750 (57%) being suspected emergencies. Of the suspected emergencies, 681 cases (25%) had a confirmed abnormality. We can confirm that telematic aids are very important for an operative station, where all kinds of emergencies must be dealt with.

Equilibrium radionuclide ventriculography in Duchenne's cardiomyopathy.

Rest and stress (handgrip) equilibrium radionuclide ventriculography was performed in 20 patients with Duchenne muscular dystrophy. The mean value of LVEF was normal, but two patients showed values below 35% and another two patients values over 70%. Mean regional wall motion values were less than 2 in lateral (posterior and inferior) and septal walls. Handgrip usually produced a reduction of LVEF and regional wall motion: in three cases severe decrease of motility was observed. Equilibrium ventriculography appears to be useful in the selection of patients with high functional cardiac involvement, integrating the characteristic ECG and echography, and, perhaps, in the assessment of myocardial tolerance to physical therapy.