The following ventilator waveforms shown below (Figure 2) are from a patient who is sedated, paralysed and ventilated in a pressure regulated volume control mode (pressure control mode with a target tidal volume). The patient has a history of bronchiectasis.
Give the most likely cause for the abnormal oscillations in the waveforms . (10% marks)
Secretions in ETT or fluid in circuit.
The college image was somewhat unlike the one I have presented here; their oscillations were much more impressive. Some of the settings on the ventilator were also different, and flow/pressure/volume loops were available (showing the exact same oscillations) However, none of that really does much to change the interpretation of this SAQ. Like a very similar SAQ from long ago (Question 5.1 from the first paper of 2012) this one tends to have only two main interpretations: either it is pus bubbling in the patient's lungs, or this is water "rain-out" collecting in the circuit.