[A model for standardized treatment and therapeutic evaluation of severe ARDS. PIF and AaDO2 quotient with a demand-adapting respirator and a conventional respirator during ARDS].

In order to achieve a uniform, easy to teach and to manage respiratory management in severe adult respiratory distress syndrome (ARDS) a combined treatment--called "step by step scheme"--was settled. It was aimed towards a regulation of the arterial blood oxygen tension at levels between 90 and 130 mmHg and this was achieved by combination of PEEP and IRV in order to minimize the inspiratory fraction of oxygen. Nine patients underwent this schedule and Benzer's AaDO2 quotient as an estimation of lung function as well as PIF (PEEP X I:E X FiO2) as quantifying parameter for the "strength" of the respirator are calculated. AaDO2 Quotient showed no statistically significant differences but PIF performed a clearly marked day of maximum respiratory support during the clinical course. This seems to be a confirmation that a variable defined by therapeutic procedures may also be an estimation of a certain degree of sickness as a pure diagnostic parameter. In plotting AaDO2 quotient versus PIF characteristically formed loops result. These loops give some evidence about the interactions between improving or worsening ARDS and properly adjusted therapeutic efforts by means of a respirator. The diagram may be also helpful in deciding conventional respirator settings or weaning procedures and show marks, where one might consider to treat by new techniques like High Frequency Ventilation, extracorporeal devices or arteriovenous hemofiltration.