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Published on: December 5, 2025

Comparison of the pressure time product during synchronous intermittent mandatory ventilation and continuous positive

T Manczur1, A Greenough, G F Rafferty

  • 1Departments of Child Health and Respiratory Medicine, King's College Hospital, London SE5 9RS, UK.

Archives of Disease in Childhood
|August 22, 2000
PubMed

Insights

Synchronous intermittent mandatory ventilation (SIMV) significantly reduces respiratory muscle work compared to continuous positive airway pressure (CPAP) in children. This suggests SIMV is a more effective weaning mode, and CPAP use should be minimized during this process.

Area of Science:

  • Pediatric critical care medicine
  • Respiratory physiology
  • Mechanical ventilation

Background:

  • Mechanical ventilation is crucial for critically ill children.
  • Weaning from mechanical ventilation requires careful management to minimize respiratory burden.
  • Pressure time product (PTP) is a key indicator of respiratory muscle workload.

Purpose of the Study:

  • To compare the efficacy of synchronous intermittent mandatory ventilation (SIMV) versus continuous positive airway pressure (CPAP) in reducing respiratory muscle work during weaning in children.
  • To quantify the difference in pressure time product (PTP) between SIMV and CPAP in pediatric patients.

Main Methods:

  • A study involving 40 children (median age 14 months) undergoing weaning from mechanical ventilation.
  • Pressure time product (PTP) was measured using airway pressure changes recorded via a pneumotachograph.
  • PTP was assessed during both SIMV (with or without pressure support) and CPAP modes.

Main Results:

  • The median PTP was significantly lower during SIMV (17.1 cm H(2)O/sec/min) compared to CPAP (32.6 cm H(2)O/sec/min) (p < 0.001).
  • This indicates a substantially reduced workload on respiratory muscles with SIMV.

Conclusions:

  • SIMV appears to be a more effective mode for weaning children from mechanical ventilation than CPAP.
  • Minimizing the duration of CPAP application during the weaning process in pediatric patients is recommended.
Abstract

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