Endotracheal Tube Block

This patient was admitted with CKD, pulmonary edema, and sepsis. Chest examination revealed crackles in both lungs. Tube block was suspected as the waveforms showed increased airway resistance that can be identified by loss of exponential decay in the inspiratory and expiratory flow time scalars and more horizontal course of the flow-time scalar.

Waveform changes associated with increased airway resistance:

1) Flow spike at the beginning of inspiration

2) Decreased peak inspiratory flow

3) Decreased slope/ more horizontal course of inspiratory flow time scalar

4) Inspiratory flow time scalar fails to reach the baseline at the end of the inspiration (indicates long time constant)

5) Flow oscillations at the beginning of expiration due to the pressure release function of the ventilator during early expiration while managing increased airway resistance

6) Loss of exponential decay of the flow-time scalar

7) Auto-PEEP/ air trapping- expiratory flow-time scalar fails to reach the baseline before the next breath

Waveform changes after changing the ET tube: 

You can notice the nice exponential decay of the expiratory flow-time scalar, increased slope of the inspiratory flow-time scalar, absence of air-trapping, and improved tidal volumes.