EtCO2, or End-Tidal Carbon Dioxide, refers to the concentration of carbon dioxide (CO2) in the gas exhaled by a patient at the end of the exhalation cycle. This critical physiological parameter is monitored in real-time by a high-precision infrared ETCO2 sensor, providing valuable data for clinical diagnosis and treatment.
The core principle of the ETCO2 sensor is based on the strong absorption characteristics of carbon dioxide molecules for specific wavelengths of infrared light. As the concentration of CO2 in exhaled gas increases, the amount of infrared light absorption by the ETCO2 sensor also increases correspondingly. The infrared ETCO2 sensor captures this change, converts the light signal into an electrical signal, which is then processed and amplified by the main control chip, and ultimately converted into readable data and intuitive waveform images for medical personnel to analyze and judge.
Monitoring ventilation function
The partial pressure of end-tidal carbon dioxide (EtCO2) is well correlated with the partial pressure of arterial carbon dioxide (PaCO2), accurately reflecting the patient's ventilation status. This helps doctors adjust the ventilator parameters in time, ensuring the patient receives enough oxygen and effectively expels excess CO2.
Determining the position of the endotracheal tube
During intubation, if the ETCO2 waveform is greater than 30mmHg, it clearly indicates that the endotracheal tube has been correctly placed in the airway, effectively avoiding risks such as incorrect insertion into the esophagus.
Reflecting circulatory function
ETCO2 levels not only reflect lung ventilation but also indirectly indicate pulmonary blood flow conditions. When ETCO2 maintains above 10-15mmHg, it indicates good pulmonary blood perfusion. In conditions such as hypotension, hypovolemia, shock, and heart failure, a reduction in pulmonary blood flow will lead to a corresponding drop in ETCO2 levels, providing doctors with important clues for evaluating circulatory function.
Timely detection of mechanical failure of the ventilator
The ETCO2 probe sensor can quickly capture issues with the ventilator or endotracheal tube connections, such as a detached endotracheal tube connector, which will lead to a rapid drop in ETCO2 to zero, or aspiration errors, which will cause a sharp increase in ETCO2, thereby timely alerting medical staff to take appropriate measures.
Adjusting ventilator parameters and guiding anesthesia
Based on the real-time changes in data monitored by the ETCO2 sensor, doctors can precisely adjust the tidal volume, respiratory rate, and other parameters of the ventilator to achieve optimal ventilation effects. Meanwhile, during anesthesia, ETCO2 is also an important indicator for assessing the depth of anesthesia and the state of awakening.
ETCO2 sensors are mainly divided into three categories: mainstream, sidestream, and microstream. Mainstream ETCO2 sensors are placed directly in the breathing circuit, providing accurate measurements but possibly affecting breathing resistance; sidestream ETCO2 sensors extract a small amount of gas from the breathing circuit for analysis via a sampling tube, having minimal impact on breathing but requiring maintenance of the sampling tube; microstream ETCO2 sensors are a recent advancement, combining the advantages of the other two types, offering higher sensitivity and lower breathing resistance.
Preheat and zeroing
Before each use, preheat the device to ensure stable operation of the ETCO2 sensor. For first-time use or after a long period of inactivity, zeroing operations should be performed to improve measurement accuracy.
Use of drying tubing
Sidestream ETCO2 sensor monitoring requires the use of drying tubing to prevent moisture in exhaled gas from affecting ETCO2 sensor performance.
Prevent liquid water ingress
During use, ensure the openings of the three-way connectors face upward to avoid liquid water entering the sampling tube. If water is detected in the adapter, stop using it immediately and dry it out.
Handling condensate
Regularly check for condensate accumulation in the tubing and promptly remove and dry it to ensure the accuracy of the measurement results.
Whether you have a question about APK Tech products or anything else, we're here to help and ready to answer your questions.
Whether you have a question about APK Tech products or anything else, we're here to help and ready to answer your questions.
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