[Registration and analysis of airway pressure and gas flow in ventilated patients. The "Hyper-DAQ Respiration Mechanics Recorder"].

Respiratory data monitored in ventilated patients commonly consists of monitoring some inspiratory and expiratory pressures and volumes. For a more sophisticated analysis of respiratory mechanics in ventilated patients, a combined hardware and software system is presented that allows for continuous monitoring of airway pressure and gas flow. Gas flow is measured using a pneumotach. The "Hyper-DAQ" is an 8-channel 12-bit analog to a digital converter that can be connected to IBM PCs as well as to Macintosh computers using a standard RS 232 link. A special module consisting of three pressure transducers (airway pressure, differential pressure for a Fleisch head and ambient pressure) and five additional analog inputs is used for recording respiratory data. Once set up, the Hyper-DAQ records all the data in real time, independently of the host system that can query the data via the RS 232 link. The software runs on IBM and compatible PCs, as well as on Macintosh computers. The software simulates a strip-chart recorder and can be controlled by the keyboard and the mouse. We developed special software for the calibration of pressure and flow. Using models of the gas distribution in the lung compliance, resistance and lung time constants can be calculated from the raw data. For special purposes the data can be transferred to spread-sheet software. A mainstream CO2-detector connected to one of the additional analog inputs allows for additional data: alveolar ventilation, series deadspace, etc. The system presented can be recommended in routine work as well as for scientific studies in ventilated patients.