An ineffective effort is defined as a patient effort that is unable to trigger the delivery of a mechanical breath.
The most common causes are:
- Trigger threshold set too high
- Pressure support too high
- Set frequency and/or inspiratory time too high (in controlled/assisted modes)
- Tidal volume set too high
- Presence of AutoPEEP
- Low respiratory drive
- Weak inspiratory effort
Several waveform characteristics can assist in the diagnosis (see Figure 1):
- The pressure/time scalar waveform will show a decrease in baseline airway pressure not followed by ventilator support
- The flow/time scalar waveform will reveal an abrupt change in the steepness of the waveform (decrease in expiratory flow or increase in inspiratory flow not followed by ventilator support)
- The esophageal pressure/time scalar waveform will display a decrease in pleural pressure not followed by ventilator support
The most practical adjustments that can be made on the ventilator to reduce ineffective efforts are as follows:
- Minimize AutoPEEP by reducing minute ventilation
- Reduce pressure support and/or tidal volume
- Adjust the expiratory trigger sensitivity (ETS) to make it more sensitive to the patient's activity (Figures 2 and 3)
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The content of this Knowledge Base is intended for informational purposes only. Medin Medical AG provides no warranty with respect to the information contained in this Knowledge Base and reliance on any part of this information is solely at your own risk. For detailed instructions on operating your Medin Medical device, please refer to the official Medin Medical Operator’s Manual for the respective device.