Monitoring respiratory function by computer in ICU. Preliminary work

The structure of the respiratory monitoring system under construction in Brussels University Hospitals is described. It is modular and hierarchized. It is based on the observation of the lung mechanics, of the flows of inspired and expired gases and of continuous blood measurements in patients artificially ventilated. Respiratory monitoring may be confined to the continuous observation of the natural evolution of a large number of parameters and the extraction of the most possible information with the aid of automatic calculations effected in real time. The authors propose to add deliberate and controlled aggressions of the pulmonary system in order to observe its dynamic behavior. Practical function tests are described. They lead to the calculation of functional residual capacity, continuous distribution of tidal volume, and pulmonary capillary blood flow. These tests can be performed automatically by using a new electronic unit built in our laboratory. It enables a digital computer to control the functioning of a commercially available ventilator.