Objective: In a randomised trial, pressure support (PS) with synchronized intermittent mandatory ventilation (SIMV) compared to SIMV alone was associated with a significant reduction in supplementary oxygen duration.
To test the hypothesis that addition of PS to SIMV compared to SIMV alone would reduce the work of breathing.
Design: Prospective study.
Setting: Perinatal service.
Patients: Twenty infants, mean gestational age 31 weeks, being weaned from mechanical ventilation were studied.
Interventions: One hour periods of SIMV and SIMV with PS at 50% of the difference between the peak inflating pressure and positive end expiratory pressure.
Main outcome measures: The work of breathing was assessed by measurement of the transdiaphragmatic pressure time product (PTPdi).
Results: The mean PTPdi on SIMV plus PS was 112 cm H2O.sec/min, approximately 20% lower than that on SIMV alone (141 cm H2O.sec/min) (p<0.001).
Conclusion: Addition of pressure support to SIMV reduces the work of breathing in infants being weaned from the ventilator.