If the patient has a pulse and is breathing, look for a problem with the capnography circuit, such as secretions in the filter or kinks in the tubing.

If the patient has a pulse and is not breathing, initiate positive pressure ventilation. If a pulse is felt, then check for breathing, because respiratory arrest will also cause a loss of ETCO2. If a capnography waveform is lost, check for a pulse immediately, and initiate CPR if one cannot be felt. This is especially true in bradycardic patients receiving transcutaneous pacing. The tracing on an ECG monitor may not even change after the patient loses pulses the patient’s heart may still have electrical activity but no pumping action. Pulse-oximetry depends on circulation at the location where the probe is placed, which is inconsistent in patients in shock or with cold extremities. Other monitoring devices are less reliable for detecting cardiac arrest.

If a waveform is produced with exhalation, some circulation is present. Waveform capnography is also useful for hypotensive patients with decreased mentation, where detection of a carotid pulse can be difficult. This is even true for patients with good air movement while receiving positive pressure ventilation. As soon as the heart stops, the capnography waveform will disappear and the ETCO2 reading will change to zero. A change in any of those will be immediately detected with waveform capnography, which is valuable information while caring for critically ill and injured patients.īesides constant palpation of a carotid pulse, waveform capnography is the most reliable prehospital monitoring device to detect the immediate loss of circulation. Loss of ETCO2 may be the first sign that CPR is neededĮnd-tidal CO2 (ETCO2) detection requires air movement in and out of the lungs (ventilation), CO2 production from cellular metabolism, and blood flow to the lungs to excrete the CO2.

End tidal capnography