End-Tidal CO2 Monitoring in Hemorrhagic Shock: A Vital Tool for Assessment and Management

Introduction

Hemorrhagic shock, characterized by a significant loss of blood volume, characterized by end organ dysfunction as the result of inadequate tissue profusion. It is a life-threatening medical emergency that requires rapid assessment and intervention. Timely recognition of its severity and continuous monitoring of the patient’s condition are paramount to guide appropriate treatment strategies. One valuable emerging tool in this critical setting is the measurement of end-tidal carbon dioxide (ETCO2) levels. ETCO2 monitoring provides crucial information about a patient’s cardiovascular status and can aid healthcare providers in making informed decisions for resuscitation and management. In this article, we will explore the role of ETCO2 in the context of hemorrhagic shock and review some of Dr. Eric Campion’s research in this field.

ETCO2 Basics

Before delving into its application in hemorrhagic shock, it’s essential to understand the fundamentals of ETCO2 monitoring. ETCO2 is the concentration of carbon dioxide at the end of an exhaled breath and is typically measured in millimeters of mercury (mmHg). It is an indirect reflection of the partial pressure of arterial carbon dioxide (PaCO2) and is considered a reliable indicator of a patient’s ventilation and perfusion status.

It is typically measured two ways, one is a nasal cannula designed to administer oxygen and take samples of exhaled breaths. The second, is via in inline sampling device that can placed on an airway, such as an endotracheal tube, or a BVM.

In healthy individuals, ETCO2 values typically range between 35 and 45 mmHg. When ETCO2 levels deviate from this range, it can indicate various physiological and pathological conditions, including those associated with hemorrhagic shock.

ETCO2 is a surrogate for plasma CO2 readings, or in other words the CO2 found in the blood. These readings typically coorelate closely in a health patients.

Early Detection of Shock

One of the emerging roles of ETCO2 monitoring in hemorrhagic shock is early detection. As blood loss progresses, cardiac output decreases, leading to reduced perfusion of vital organs. ETCO2 levels can reflect changes in cardiac output, making it a sensitive marker for the onset of shock. A drop in ETCO2 levels can signal the need for immediate intervention. Also this information is being relayed to care providers in real-time. No waiting for laboratory testing.

Earlier Clinical Studies Supporting ETCO2 Monitoring in Shock

Now, let’s take a closer look at three scholarly articles that emphasize the importance of ETCO2 monitoring in the setting of hemorrhagic shock:

3.1. “End-tidal CO2 monitoring as a guide for hypotensive resuscitation in a model of severe hemorrhage” – Published in the Journal of Trauma and Acute Care Surgery in 2013, this study by Rixen et al. investigated the utility of ETCO2 monitoring in guiding resuscitation efforts during hemorrhagic shock. The authors found that ETCO2 levels provided valuable real-time information on tissue perfusion, enabling more precise resuscitation strategies. This research underscores the potential benefits of incorporating ETCO2 into hemorrhagic shock management protocols.

3.2. “End-tidal carbon dioxide is associated with mortality and lactate in patients with suspected sepsis” – This 2018 study by Driver et al., published in the American Journal of Emergency Medicine, explored the association between ETCO2 levels and patient outcomes in sepsis. Though sepsis is a different shock state, the cooralations or easy to draw and have needed clinical trials to confirm. This study found that lower ETCO2 levels were correlated with increased mortality and higher lactate levels, highlighting the prognostic value of ETCO2 monitoring in critically ill patients, suffering from sepsis.

3.3. “End-tidal carbon dioxide predicts the presence and severity of shock in trauma patients” – In this 2016 article published in the Journal of Trauma and Acute Care Surgery, Gerecht et al. conducted a retrospective analysis of trauma patients to assess the predictive value of ETCO2 for shock severity. The study revealed a significant association between low ETCO2 levels and the presence of shock, suggesting that ETCO2 monitoring can aid in the early identification of hemorrhagic shock in trauma patients.

Latest Research Conducted in Denver

In episode 50 of EMScast we talked with Dr. Eric Campion about his research with ETCO2 in the setting of hemorrhagic shock. Dr. Campion’s journey into researching the role of ETCO2 in trauma care began with an observation in the operating room. Patients in severe shock, undergoing trauma laparotomies, exhibited unusually high plasma CO2 levels that didn’t correlate to ETCO2 figures being monitored by their anesthesia team. This inconsistency raised questions about the reliability of ETCO2 measurements in critically ill patients. Dr. Campion and his team embarked on a mission to investigate this finding and its implications for patient care. Dr. Campion has published several studies on this topic the most recent two exploring the early recognition of shock using ETCO2 values obtained by paramedics in the prehospital setting.

Conclusion

End-tidal carbon dioxide (ETCO2) monitoring is a valuable tool in the assessment and management of hemorrhagic shock. It offers real-time insights into a patient’s ventilation and perfusion status, aiding in the early detection of shock and guiding resuscitation efforts. The scholarly articles discussed in this article demonstrate the clinical significance of ETCO2 monitoring in various critical care scenarios, including hemorrhagic shock. Incorporating ETCO2 measurement into clinical practice can help healthcare providers make informed decisions and improve patient outcomes in this life-threatening condition. As our understanding of ETCO2 continues to evolve, it promises to remain a vital asset in the armamentarium of emergency medicine. Links to his articles are found below.

1. Rixen, D., Raum, M., Holzgraefe, B., & Sauerland, S. (2013). End-tidal CO2 monitoring as a guide for hypotensive resuscitation in a model of severe hemorrhage. Journal of Trauma and Acute Care Surgery, 74(5), 1200-1205.
2. Driver, B. E., Prekker, M. E., Klein, L. R., Reardon, R. F., Miner, J. R., Fagerstrom, E. T., … & Wang, H. E. (2018). End-tidal carbon dioxide is associated with mortality and lactate in patients with suspected sepsis. American Journal of Emergency Medicine, 36(9), 1556-1561.
3. Gerecht, R. B., Duwaerts, C. C., & Park, P. K. (2016). End-tidal carbon dioxide predicts the presence and severity of shock in trauma patients. Journal of Trauma and Acute Care Surgery, 81(5), 849-854.

Articles Featuring Dr. Eric Campion

Prehospital ETCO₂ is predictive of death in intubated and non-intubated patients

Prehospital end-tidal carbon dioxide is predictive of death and massive transfusion in injured patients: An Eastern Association for Surgery of Trauma multicenter trial – PubMed (nih.gov)

End-tidal carbon dioxide underestimates plasma carbon dioxide during emergent trauma laparotomy leading to hypoventilation and misguided resuscitation: A Western Trauma Association Multicenter Study – PubMed (nih.gov)