From the Guidelines
True, EtCO2 monitoring can be used on both intubated and non-intubated patients. For intubated patients, EtCO2 monitoring is typically performed through a sensor placed in-line with the ventilator circuit that directly measures exhaled CO2 levels, as noted in the 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care 1. For non-intubated patients, EtCO2 can be monitored using nasal cannulas with CO2 sampling capability or specialized face masks with built-in sampling ports.
The technology works by measuring the concentration of carbon dioxide at the end of exhalation, which reflects alveolar ventilation and indirectly indicates perfusion status. In intubated patients, EtCO2 confirms proper endotracheal tube placement and monitors ventilation adequacy, while in non-intubated patients, it can detect respiratory depression, assess response to treatments, and monitor patients receiving procedural sedation. However, it's crucial to consider the limitations and potential inaccuracies of EtCO2 measurements in non-intubated patients, as highlighted in the same guidelines update 1, which emphasizes that EtCO2 levels may not consistently reflect the true value in such cases.
Key points to consider include:
- EtCO2 monitoring is valuable for assessing ventilation and perfusion status in both intubated and non-intubated patients.
- The method of EtCO2 measurement may vary between intubated and non-intubated patients, with intubated patients typically using in-line sensors with the ventilator circuit and non-intubated patients using nasal cannulas or specialized face masks.
- The normal EtCO2 range is typically 35-45 mmHg, with values outside this range potentially indicating respiratory or circulatory problems, as discussed in the context of cardiopulmonary resuscitation guidelines 1.
- Clinical guidelines, such as those from the American Heart Association, provide recommendations on the use of EtCO2 in different clinical scenarios, including its role in prognostication during CPR and in monitoring patients receiving emergency care 1.
From the Research
EtCO2 Monitoring
- EtCO2 can be used on both intubated and non-intubated patients, as shown in a study published in 2007 2.
- The study found that sidestream EtCO2 monitoring is feasible during air medical transport of both intubated and non-intubated patients.
- However, another study published in 2016 found that transcutaneous CO2 measurement may be more accurate than EtCO2 in nonintubated ICU patients with acute respiratory failure 3.
- A study published in 2017 found that EtCO2 often provides inadequate instrument sensitivity when detecting changes in ventilation in non-intubated patients undergoing procedural sedation 4.
- A comparison of flow-through and sidestream capnometry found that both methods performed equally well in non-intubated, sedated patients 5.
- EtCO2 is also used to confirm endotracheal tube placement in patients requiring general anesthesia, although upper airway ultrasonography may be a promising alternative method 6.
Key Findings
- EtCO2 monitoring can be used in both intubated and non-intubated patients.
- The accuracy of EtCO2 monitoring may vary depending on the patient's condition and the method used.
- Alternative methods, such as transcutaneous CO2 measurement and upper airway ultrasonography, may be more accurate or reliable in certain situations.