Volume-controlled intermittent mandatory ventilation in preterm infants with hypoxemic episodes

Abstract

Objective: To test the hypothesis in ventilated very low birth weight infants with frequent hypoxemic episodes that volume-controlled synchronized intermittent mandatory ventilation (SIMV) vs. pressure-controlled SIMV reduces by at least 20% the time with hypoxemia (defined as SpO(2)<80%).

Design: Randomized cross-over design.

Setting: University-based tertiary neonatal intensive care unit.

Patients: 15 mechanically ventilated very low birth weight infants with frequent hypoxemic episodes.

Interventions: The infants were exposed in random order to volume-controlled and pressure-controlled SIMV for 4 h each. The target tidal volume during volume-controlled SIMV was matched to the tidal volume measured during pressure-controlled SIMV. FIO(2) was adjusted using uniform criteria to maintain SpO(2) within the target range (SpO(2) 80-92%).

Measurements and results: Primary outcome measure was the time with an SpO(2)<80%. Although tidal volume was maintained better during desaturations with volume-controlled SIMV, there was neither a significant difference in time with an SpO(2)<80% (expressed as proportion of total experimental time; median, interquartile range)-volume-control 10.6% (9.2-13.7%) vs. pressure-control 10.8% (8.3-13.3%)-nor in FIO(2) exposure. During volume-controlled SIMV the infants spent less time with an SpO(2) above the target range and had fewer associated bradycardias.

Conclusion: Volume-controlled SIMV did not decrease the time with an SpO(2)<80%, although tidal volume was better maintained during these episodes and bradycardias were less frequent than with pressure-controlled SIMV in this population of very low birth weight infants with frequent hypoxemic episodes.