Identifying Increased Airway Resistance in Pressure Control Mode

In pressure control mode, increased airway resistance alters the inspiratory flow waveform in the following ways:

• Reduced peak inspiratory flow

• Flattening of normal exponential decay, resulting in a decreased slope

• Flow may fail to return to baseline before expiration, reflecting long time constant

Similar abnormalities can also be seen in the expiratory flow-time curve (loss of normal exponential decay). Additionally, air trapping/ auto PEEP can be noticed at the end of expiratory phase.