Article Text

other Versions

Work of breathing during SIMV with and without pressure support
  1. Deena Shefali Patel (deena.s.patel{at}
  1. King's College London, United Kingdom
    1. Gerrard F Rafferty (gerrard.rafferty{at}
    1. King's College London, United Kingdom
      1. Silke Lee (silke.lee{at}
      1. King's College London, United Kingdom
        1. Simon Hannam (simon.hannam{at}
        1. King's College London, United Kingdom
          1. Anne Greenough (anne.greenough{at}
          1. King's College London, United Kingdom


            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.

            Statistics from

            Request permissions

            If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.