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 end-expiratory pressure modifications by ASV-CO2-O2.
Trial registration: ClinicalTrials.gov: NCT01095406.