Question: What is the error in this infographic?
According to the infographic, cardiac arrest causes a sudden complete loss of waveform. This isn't correct. Cardiac arrest will cause a prompt downtrending etCO2 tracing (the pattern shown in the bottom right box).
This is clinically important because if a patient in cardiac arrest is intubated, there should be some waveform capnography tracing present. The etCO2 will often be very low (e.g. 5-10 mm), but a tracing should be seen. If a completely flat trace occurs, the endotracheal tube is probably in the esophagus. Other possibilities may include a disconnection in the ventilator tubing or a dysfunctional etCO2 sensor (ideally the sensor was tested prior to intubation).
But the key point is that a completely flat etCO2 tracing should be assumed to indicate a misplaced endotracheal tube until proven otherwise. This is taught in airway management using the mantra “no trace, wrong place.”
For more on this, take a look at the Royal College of Anaesthetists “no trace, wrong place” campaign. Yup, it's a campaign. Who knew?
Late to the party and hate to play the “what ifs”, but what if non-invasive end tidal monitoring is in place? That’s the only scenario I envision.