Evaluation of the expert system for respiratory therapy of newborns on archival data.

The aim of this study was to evaluate the artificial ventilation expert system for neonates (AVES-N) using archival data. The recommendations of the system were compared to the decisions made by the expert-physician in the same clinical situation (patient condition, respirator settings). In our retrospective study we used data of 320 newborns which were ventilated in the Neonatal Intensive Care Unit of the Vanderbilt University Hospital in Nashville (USA).

Inhibition of phrenic nerve activity during positive-pressure ventilation at high and low frequencies.

A study was made to determine whether the ventilatory pattern, in terms of ventilatory frequency, insufflation period and end-expiratory pressure, influences the arterial blood gas level at which central inspiratory activity is inhibited, and whether further expansion of the lung changes this activity. This was accomplished by measuring arterial pH and blood gases, and intratracheal, intrapleural and transpulmonary pressures, at the setting of positive-pressure ventilation causing inhibition of phrenic nerve activity in chloralose-anaesthetized cats. Spontaneous breathing movements were prevented by muscle relaxation.

Alveolar deadspace during high frequency positive pressure ventilation. Influence of ventilatory pattern.

Pulmonary gas exchange was studied in association with high frequency ventilation and its relation to the duration of insufflation and end-expiratory pressure investigated. Alveolar deadspace, alveolar ventilation and the alveolar-arterial oxygen difference were obtained in cats receiving a constant minute ventilation. Alveolar deadspace increased with ventilatory frequency when a long insufflation time was used.