How is carbon dioxide level in breath checked?

How is carbon dioxide level in breath checked?

Most of you may be aware that oxygen level in blood can be easily checked by keeping a small device known as pulse oximeter on your finger. But carbon dioxide level cannot be checked with that device. Blood carbon dioxide level can be checked by taking a blood sample from the artery and analyzing it in the blood gas analyzer.
Artery is a blood vessel carrying oxygenated blood to a part of the body. Carbon dioxide level in the air you breath out can be checked by collecting a small sample and analyzing it in a device. Instantaneous values can be displayed on a monitor as well.
This screen shot of an intensive care monitor shows ECG, breathing rate, blood pressure, pulse oximetry and breath carbon dioxide from top to bottom. Instantaneous tracings are seen, and corresponding numerical values shown on one side of the display. Carbon dioxide tracing has been labelled as ETCO2. ETCO2 stands for end tidal carbon dioxide, meaning that the value at the end of breathing out is displayed. Carbon dioxide monitoring is also known as capnography.
Capnography is useful after putting a tube in the windpipe to confirm the position of the tube in the windpipe and is used routinely in most modern centres in the emergency department. This will make sure that the tube has not gone into the food pipe. Carbon dioxide sensor is attached to the air tubing.
ETCO2 monitoring is common place in the operating room and most of the state-of-the-art intensive care units. Capnography provides instantaneous information on breathing, whether the cells are getting enough blood and working well to produce carbon dioxide after utilizing oxygen in the blood.
Hence ETCO2 monitoring is useful in assessing the effectiveness of artificial breathing and cardiopulmonary resuscitation. Artificial breathing is given by a device known as ventilator when the person is not able to breathe well due to some reason or when under general anaesthesia.
Cardiopulmonary resuscitation is given as an emergency life support measure when the heart has stopped beating. Regular chest compressions and artificial breaths are given during CPR. Carbon dioxide monitoring during CPR tells you whether your chest compressions and artificial breaths are adequate so that cells get enough blood and oxygen to maintain life. This helps to improve the quality of CPR.