capnografía

Capnography is a non-invasive method used to measure and display the concentration of carbon dioxide (CO2) in a patient's exhaled breath. It provides real-time information about ventilation, circulation, and metabolism. The device used is called a capnograph, and it typically displays the CO2 level as a waveform, known as a capnogram, and a numerical value.

The primary use of capnography is in monitoring patients undergoing mechanical ventilation or anesthesia. It helps confirm endotracheal tube placement, as CO2 should be detected in the lungs but not in the esophagus. It also allows for continuous assessment of the adequacy of ventilation, helping clinicians detect hyperventilation or hypoventilation. Changes in the capnogram waveform can indicate various physiological events, such as bronchospasm, pulmonary embolism, or cardiac arrest.

In addition to monitoring, capnography can be used in critical care settings to assess the effectiveness of chest compressions during cardiopulmonary resuscitation. A sudden increase in end-tidal CO2 during CPR can indicate the return of spontaneous circulation. The technology relies on infrared spectroscopy to measure CO2. The capnogram waveform typically shows an initial phase with minimal CO2, followed by a rise as CO2 from the alveoli is exhaled, and then a plateau representing alveolar CO2. A sharp decline or absence of the waveform can signal a critical event. Capnography is a valuable tool for improving patient safety and guiding clinical decisions.