Experience with continuous monitoring of lungcompliance and airway resistance

Recently the Auprem apparatus is developed and enables to compute automatically on line the values of compliance and airway resistance, by means of a pneumotachograph. The application in anesthesiology are manifold. As illustration, a study of enflurane (Ethrane) on respiratory dynamics is described. In a group of 10 patients, we found a slight although not significant decrease of airway resistance by +/- 10% (5.2 +/- 0.5 before enflurane and 4.9 +/- 0.4 cm H2O/1/sec. after enflurane). Elastance was nearly unchanged as well as compliance. Some examples of the study of ventilation patterns are given. In a same patient the Engström respirator 300 and the Servoventilator with constant flow pattern and with increasing flowpattern are compared. When the plateau phase is suppressed, the computed values of airway resistance and elastance differ markedly. The ability to use central venous pressure instead of oesophagial pressure is an important innovation and opens a new research area for studying critical care patients.