Recent experience with a respiratory monitoring system in intensive care.
Computer based instrumentation for continuous monitoring of airway flow, pressure, O2 and CO2 concentration offers an improved noninvasive management technique for patients on mechanical ventilators. Computation of these basic signals provides routinely the following measurements: respiratory rate, tidal volume in and out, minute ventilation, positive end-expiratory pressure, mean airway pressure, inspiration-expiration ra measurements, except for O2 consumption and partially for tco2 production. The system works as a monitor of the respirator (detection of malfunction) and as a monitor of the lung function of the patient. It is particularly useful when adjusting the respirator and at time of weaning a patient from the respirator. These maneuvers can be made more safely because they are based on objective measurements and followed by immediate new sets of data. Defining the optimal values of tidal volume and positive end-expiratory pressure has been simplified by the use of pressure-volume plots. A "fighting", is now used as a measure of the severity of "fighting", that is of the effort of the patient to breathe spontaneously while being ventilated. It can detect fighting before it is diagnosed clinically and so can provide a warning that significant physiological changes will occur unless the fighting is controlled. New information about the distribution of ventilation-perfusion ratio can be derived from the expired concentration curve for CO2. Quantitative measurement of the distribution of ventilation shows a very close correlation with clinical events and can be carried out automatically during the normal routine of care of the patient. These on-line quantitative measurements, with the immediate reporting of results, appear to make a positive contribution to patient care.
D001530:Belgium; D003201:Computers; D006801:Humans; D007362:Intensive Care Units; D008991:Monitoring, Physiologic; D012129:Respiratory Function Tests / Q000379:methods*; D012122:Ventilators, Mechanical