From the Guidelines
End-tidal carbon dioxide (ETCO2) monitoring has significant value beyond assessing return of spontaneous circulation (ROSC) in cardiac arrest, and its applications extend to various clinical scenarios. ETCO2 is utilized for confirming endotracheal tube placement, where a reading above 10 mmHg indicates proper placement in the trachea rather than the esophagus 1. It serves as a continuous ventilation monitor during procedural sedation, where decreasing values may indicate respiratory depression requiring intervention. In mechanically ventilated patients, it helps optimize ventilator settings and can detect disconnections or circuit problems. During CPR, ETCO2 values reflect the quality of chest compressions, with values below 10-15 mmHg suggesting inadequate technique, as supported by guidelines from the American Heart Association 1. For patients with respiratory conditions like asthma or COPD, trending ETCO2 helps assess treatment effectiveness, while in trauma patients, falling ETCO2 may indicate developing shock.
Key Applications of ETCO2 Monitoring
- Confirming endotracheal tube placement
- Continuous ventilation monitoring during procedural sedation
- Optimizing ventilator settings in mechanically ventilated patients
- Assessing quality of chest compressions during CPR
- Evaluating treatment effectiveness in respiratory conditions
- Detecting potential shock in trauma patients ETCO2 monitoring works because exhaled carbon dioxide reflects ventilation, perfusion, and metabolism, making it a valuable vital sign across multiple clinical scenarios. The most recent and highest quality study, from 2021, suggests that maintaining an ETCO2 ≥ 10 mmHg during advanced life support may be reasonable in patients with perioperative cardiac arrest 1. This highlights the importance of considering ETCO2 in the context of the patient’s clinical status and individualizing targets based on the cause of arrest, degree of hypoxia, quality of CPR, and time to ROSC.
From the Research
EtCO2 in Non-ROSC Circumstances
- EtCO2 is used in various medical circumstances beyond Return of Spontaneous Circulation (ROSC), including:
- Procedural sedation: EtCO2 monitoring has been evaluated in non-intubated patients undergoing procedural sedation, showing that it may not be reliable in detecting changes in ventilation 2.
- Trauma surgery: Low EtCO2 values at the onset of emergent trauma surgery have been associated with nonsurvival, suggesting its potential use in guiding decision-making 3.
- Laparoscopic surgery: EtCO2 monitoring has been used to assess the effects of carbon dioxide insufflation on acid-base status during laparoscopy, showing a correlation between EtCO2 and PaCO2 4.
- General anesthesia: Outlying EtCO2 values during general anesthesia have been linked to postoperative pulmonary complications, with a median EtCO2 range of 35-38 mmHg associated with the lowest incidence of complications 5.
- Non-invasive mechanical ventilation: EtCO2 values have been compared to blood gas PCO2 values in patients receiving non-invasive mechanical ventilation, showing significant differences between the two measurements 6.
Clinical Applications
- EtCO2 monitoring can be used to:
- Assess ventilation in non-intubated patients undergoing procedural sedation 2.
- Guide decision-making in emergent trauma surgery 3.
- Monitor acid-base status during laparoscopy 4.
- Predict postoperative pulmonary complications in patients undergoing general anesthesia 5.
- Evaluate the effectiveness of non-invasive mechanical ventilation 6.
Limitations and Considerations
- EtCO2 monitoring may not be reliable in all clinical situations, such as in non-intubated patients undergoing procedural sedation 2.
- The correlation between EtCO2 and PaCO2 may vary depending on the clinical context 4, 6.
- Further research is needed to fully understand the clinical applications and limitations of EtCO2 monitoring in non-ROSC circumstances 2, 3, 5, 6.