A pilot prospective study on closed loop controlled ventilation and oxygenation in ventilated children during the weaning phase.

Introduction: The present study is a pilot prospective safety evaluation of a new closed loop computerised protocol on ventilation and oxygenation in stable, spontaneously breathing children weighing more than 7 kg, during the weaning phase of mechanical ventilation. Methods: Mechanically ventilated children ready to start the weaning process were ventilated for five periods of 60 minutes in the following order: pressure support ventilation, adaptive support ventilation (ASV), ASV plus a ventilation controller (ASV-CO₂), ASV-CO₂ plus an oxygenation controller (ASV-CO₂-O₂) and pressure support ventilation again. Based on breath-by-breath analysis, the percentage of time with normal ventilation as defined by a respiratory rate between 10 and 40 breaths/minute, tidal volume > 5 ml/kg predicted body weight and end-tidal CO₂ between 25 and 55 mmHg was determined. The number of manipulations and changes on the ventilator were also recorded. Results: Fifteen children, median aged 45 months, were investigated. No adverse event and no premature protocol termination were reported. ASV-CO₂ and ASV-CO₂-O₂ kept the patients within normal ventilation for, respectively, 94% (91 to 96%) and 94% (87 to 96%) of the time. The tidal volume, respiratory rate, peak inspiratory airway pressure and minute ventilation were equivalent for all modalities, although there were more automatic setting changes in ASV-CO₂ and ASV-CO₂-O₂. Positive end-expiratory pressure modifications by ASV-CO₂-O₂ require further investigation. Conclusion: Over the short study period and in this specific population, ASV-CO₂ and ASV-CO₂-O₂ were safe and kept the patient under normal ventilation most of the time. Further research is needed, especially for positive endexpiratory pressure modifications by ASV-CO₂-O₂. [ABSTRACT FROM AUTHOR]