Characteristics of the ventilator pressure- and flow-trigger variables

Area of Science:

• Mechanical Ventilation
• Respiratory Physiology

Background:

• Pressure- and flow-triggering are key features in modern mechanical ventilators.
• Continuous positive airway pressure (CPAP) modes are widely used for respiratory support.
• Understanding ventilator triggering mechanisms is crucial for optimizing patient-ventilator synchrony.

Purpose of the Study:

• To compare the triggering characteristics of pressure- and flow-triggered CPAP between the Puritan Bennett 7200ae and Siemens SV 300 ventilators.
• To evaluate the impact of these triggering methods on the lung pressure-time product (total PTP) using a mechanical lung model.

Main Methods:

• Utilized a mechanical lung model to assess ventilator performance.
• Measured the total pressure-time product (PTP) for pressure- and flow-triggered CPAP on both ventilator models.
• Investigated the effect of applying 5 cmH2O pressure support.

Main Results:

• The Puritan Bennett 7200ae exhibited a greater total PTP with pressure-triggered CPAP compared to flow-triggered CPAP due to insufficient flow delivery.
• Total PTP was comparable between pressure- and flow-triggered CPAP in the Siemens SV 300.
• The Siemens SV 300 demonstrated lower total PTP than the Puritan Bennett 7200ae for both triggering methods.
• Applying minimal pressure support to the Puritan Bennett 7200ae eliminated the difference in total PTP between triggering modes.

Conclusions:

• Ventilator triggering mechanisms and specific ventilator models significantly influence the work of breathing, as indicated by total PTP.
• The Siemens SV 300 appears more efficient in delivering CPAP compared to the Puritan Bennett 7200ae.
• Further research is needed to determine the clinical implications of these findings on patient inspiratory muscle work.