Abstract

Objective: In a randomised trial, pressure support with synchronised intermittent mandatory ventilation (SIMV) compared to SIMV alone was associated with a significant reduction in supplementary oxygen duration. The hypothesis that the addition of pressure support to SIMV compared to SIMV alone would reduce the work of breathing was examined.

Design: Prospective study.

Setting: Perinatal service.

Patients: 20 infants, with a mean gestational age of 31 weeks, being weaned from mechanical ventilation were studied.

Interventions: 1 h periods of SIMV and SIMV with pressure support at 50% of the difference between the peak inflating pressure and positive end expiratory pressures.

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 pressure support was 112 cm H₂O.s/min, approximately 20% lower than that on SIMV alone (141 cm H₂O.s/min) (p<0.001).

Conclusion: The addition of pressure support to SIMV reduces the work of breathing in infants being weaned from the ventilator.