A crossover analysis of mandatory minute ventilation compared to synchronized intermittent mandatory ventilation in neonates

Background: Mandatory minute ventilation (MMV) is a novel ventilator mode that combines synchronized intermittent mandatory ventilation (SIMV) breaths with pressure-supported spontaneous breaths to maintain a desired minute volume. The SIMV rate is automatically adjusted to maintain minute ventilation. Objective: To evaluate MMV in a cohort of infants without parenchymal lung disease alternately ventilated by MMV and SIMV. Design/methods: Neonates >33 weeks' gestational age and electively intubated for medical or surgical procedures were enrolled. Exclusionary criteria included: nonintact respiratory drive or active pulmonary disease. Infants were randomized to receive 2 hours of either SIMV or MMV and then crossed over to the other mode for 2 hours. Ventilator parameters and end-tidal CO₂ (etCO₂) were measured via inline, mainstream monitoring and recorded every minute. Results: In total, 20 infants were evaluated. No statistically significant differences were found for overall means between etCO₂, minute volumes, peak inspiratory pressure (PIP), or positive end expiratory pressure (PEEP). However, there was a significant difference in the type of ventilator breaths given and in the mean airway pressure. Additionally, there was a statistically significant negative trend in MMV over time compared to SIMV, although this was subtle and could have been due to extreme cases. Conclusions: Neonates with an intact respiratory drive can be successfully managed with MMV without an increase in etCO2. While this mode generates similar PIP and PEEP, the decrease in mechanical breaths and the mean airway pressure generated with MMV may reduce the risk of some of the long-term complications associated with mechanical ventilation.