capnometers

A capnometer is a medical device used to measure and display the concentration of carbon dioxide in exhaled breath. This measurement is known as end-tidal carbon dioxide (ETCO2). Capnometry is a non-invasive technique that provides real-time information about a patient's ventilation, circulation, and metabolism. The device works by passing a beam of infrared light through a sample of exhaled gas. Carbon dioxide absorbs infrared light at a specific wavelength, and the amount of light absorbed is proportional to the CO2 concentration. This information is then processed and displayed as a numerical value and often as a waveform on a monitor.

Capnography, which is the graphical display of expired CO2 over time, is often performed in conjunction with capnometry. The resulting waveform, called a capnogram, provides additional diagnostic information. Capnometers are commonly used in anesthesia, intensive care units, emergency medicine, and during cardiopulmonary resuscitation. They are essential for monitoring the adequacy of ventilation, detecting esophageal intubation, confirming endotracheal tube placement, and assessing the effectiveness of chest compressions. Changes in ETCO2 levels can indicate various physiological events, such as changes in cardiac output, pulmonary blood flow, or metabolic rate.