PubMed Health⌕ Search

Biomedical subjects

F Huber

Publications and source records attributed to F Huber.

At least 37 records · Page 2Linked to original sources
PubMed1976

On-line cardiac output by digital computer.

Many devices for fast cardiac output calculations employ special assumptions and departures from the Stewart-Hamilton method. These assumptions and departures can cause substantial errors. This publication describes an on-line computer system for evaluating dye-dilution curves according to the classical Stewart-Hamilton method. Dilution curves are smoothed, using a digital filter to eliminate heartbeat noise. Recirculation is removed using the constant ratio property of exponentials. The quality of the curves is evaluated by determining the length of the base line, the extent and the fit to an exponential downslope, and a figure of merit based on the five tanks-in-series model. Dilution curves, the logarithmic form, and the exponential ratios are displayed on a CRT for visual checks. Comparison of cardiac outputs obtained by this on-line system with results obtained by hand calculations showed a mean difference of 150 ml. Repeated evaluation of one electronically simulated dye curve resulted in SD = 10 ml for computer results and SD = 200 ml for hand calculations.

Animals↗
PubMed1976

On-line impedance analysis system for studying the pulmonary vascular response to hypoxia.

The response of the pulmonary circulation to hypoxia is generally assessed in terms of cardiac output and pulmonary vascular resistance. However, due to pulsatility, the opposition to blood flow can be described accurately only by the input impedance to the pulmonary bed. For assessment of impedance, a system was developed consisting of implantable pressure transducers and an improved muitichannel continuous wave Doppler flow meter. A computer system was used to analyze the data, which was based on power output of the right heart, power dissipation in the pulmonary circulation, and impedance spectra. Data have been obtained from dogs exposed to various levels of acute hypoxia.

Animals↗