Characteristics of the ventilator pressure- and flow-trigger variables.
Pressure- and flow-triggering are available in the Puritan Bennett 7200ae and Siemens SV 300. Using a mechanical lung model, we described the characteristics of the pressure- and flow-triggered continuous positive airway pressure (CPAP) of both ventilators. In the Puritan Bennett 7200ae, the pressure-triggered CPAP is characterized by the relatively insufficient flow delivery after the triggering, resulting in a greater lung pressure-time product (total PTP) than the flow-triggered CPAP. Pressure support of 5 cmH2O results in total PTP less than that with flow-triggered CPAP. In the Siemens SV 300, total PTP with pressure- or flow-triggered CPAP is comparable. Total PTP is less with pressure- or flow-triggered CPAP of the Siemens SV 300 than that of the Puritan Bennett 7200ae, respectively. The application of small pressure- or flow-triggered pressure support in the Puritan Bennett 7200ae eliminates the difference. The impact of these differences on patient inspiratory muscle work remains to be determined.
Sassoon
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Pulmonary and Critical Care Section, UCI-Long Beach Medical Program, Veterans Affairs Medical Center, CA 90822, USA.
Gruer
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D000399:Air Pressure; D006801:Humans; D008838:Microcomputers; D011175:Positive-Pressure Respiration / Q000295:instrumentation; D014160:Transducers, Pressure; D012122:Ventilators, Mechanical; D014939:Work of Breathing