What indicates normal carbon dioxide movement through the respiratory system on capnography?

A waveform with a square shape on capnography indicates normal carbon dioxide movement through the respiratory system. This square shape reflects a consistent and effective exhalation phase where carbon dioxide is being expelled from the lungs. In a healthy individual, the capnography waveform rises sharply as CO2-rich air is exhaled, peaking when the lungs empty and then falling back down as inhalation begins again.

The square waveform is characteristic of normal ventilation, where the rate and depth of breathing are sufficient to allow for the adequate exchange of gases in the lungs. This shape provides a clear indication that there is a steady flow of carbon dioxide, confirming that both ventilation and perfusion are occurring appropriately within the lungs. Maintaining this function is crucial for preventing hypercapnia or hypoxia, conditions that can result in serious physiological effects.

In contrast, other waveform appearances such as a flat waveform or jagged waveform would suggest abnormalities in breath mechanics or gas exchange and could indicate issues such as inadequate ventilation, obstruction, or lung disease, which do not reflect normal carbon dioxide movement.