What Is Capnography (Continued)

The measurement of carbon dioxide (CO2) in exhaled air over time, capnography can be used to diagnose diseases, gauge their severity, and measure the response to treatment. Carbon dioxide concentrations are represented as a waveform. Thus, waveform capnography is effective at measuring what’s known as tidal carbon dioxide.

The maximum CO2 concentration at the end of each tidal breath, or end-tidal CO2 (EtCO2), helps see how severe a respiratory problem is and how to adapt a given treatment method to the patient’s condition.

Capnography is used by medical services personnel to assess a patient’s:

• Ventilation: How efficiently the pulmonary system is eliminating CO2
• Perfusion: The ability of the vascular system to transport CO2
• Metabolism: The efficiency of cellular metabolism in producing CO2

By contrast, pulse oximetry provides real-time information on oxygenation. Along with ventilation, this is also a physiologic respiratory function measured in patients who are intubated or who can breathe on their own.

How Is Respiratory CO2 Measured?

Monitoring the partial pressure of carbon, or its gas concentration in exhaled air, can be accomplished with mainstream sensors placed in the airway. In this configuration, the sensor is placed on an endotracheal tube’s airway adapter. A side-stream sensor measures respiratory gas by sampling it via a nasal or nasal-oral cannula. Small samples of exhaled breath are aspirated through the tubing to the monitor’s sensor.

When Is Capnography Used?

By measuring ETCO2, it’s possible to track respiratory effort in addition to other important parameters, such as the respiratory rate and sounds of a patient’s breath. It can be used when the brain doesn’t respond to changes in carbon dioxide, which can happen in cases of a head injury, seizure, or overdose.

Patients with conditions such as asthma, pneumonia, or chronic obstructive pulmonary disease may struggle to get air out. Waveform capnography can be used to measure their effort vs. how effectively their bodies are eliminating CO2. Changes in tidal volume can cause EtCO2 levels to rise or fall.

These measurements can also help to provide real-time feedback on treatments such as medications and bag valve masks or to determine how fast a patient should be ventilated. This is important since under- or over-ventilating a patient can cause serious harm. Low EtCO2 levels can accompany other signs of shock and provide clues about circulation to the lungs and body. The ideal EtCO2 range is around 35-45 mmHg.1

Where Do I Find the Best Capnography Equipment?

Medical Device Depot carries leading-brand waveform capnography systems from Welch Allyn, Criticare, and Masimo. We offer standalone CO2 monitors and multifunctional units that measure carbon dioxide output and other parameters.

Order your equipment directly online, and receive competitive financing, or call 877-646-3300 for information or help finding the equipment needed to provide critical care to patients. We offer worldwide shipping and accept purchase orders.

Source:

1. https://www.jems.com/articles/print/volume-42/issue-8/features/how-to-read-and-interpret-end-tidal-capnography-waveforms.html