Should EMS Monitor EtCO2? Yes!

Scott Stoneburner

Emergency Medical Service and Capnography Monitoring

The Surviving Sepsis campaign recommends measuring blood lactate level to guide the identification of tissue hypoperfusion and initiation of treatment.⁴ However, obtaining blood lactate can frequently be delayed, which may postpone recognition and treatment.⁵Microstream™ EtCO2 provides a rapid, non-invasive measure that correlates with blood lactate and can be performed in a pre-hospital setting.^2,3 Microstream™ EtCO2 measurements may give EMS providers additional accuracy to detect suspected sepsis during pre-hospital screening.

In this blog post you’ll learn how:

Early recognition of sepsis can be associated with improved outcomes⁶
EtCO2 monitoring provides a rapid, non-invasive measure that correlate with blood lactate^2,3
To implement a prehospital sepsis screening program with Microstream™ capnography¹

Related: Learn more about Sepsis and End-tidal CO2 in the emergency department.

Early Recognition of Sepsis is Associated with Improved Outcomes⁶

Early recognition and timely intervention are key to improving outcomes in septic patients.⁶ However, often the early presentation of sepsis is subtle and can go unrecognized. For example, a retrospective review of ED patients requiring ICU transfer found that sepsis patients tend to spend more time in the ED prior to transfer, resulting in the delayed care. ⁷ This circumstance is especially problematic for sepsis patients as delayed treatment can lead to adverse outcome. For example, Kumar et al. found that each hour that antimicrobial treatment is delayed, mortality increases 7.6 percent. ⁸

Consequently, the Society for Critical Care Medicine and European Society of Intensive Care Medicine developed the Surviving Sepsis Campaign Hour-1 Bundle, which identifies the most critical actions you should implement to assure early recognition and immediate intervention in adult patients presenting with sepsis or septic shock.⁴ The initial step in the bundle involves measuring serum lactate as a prognostic marker for patients who are at-risk for end-organ dysfunction and are eligible for aggressive resuscitation therapy.⁴ Unfortunately, receiving lactate values may significantly delay the initiation of treatment. For example, Goyal et al. determined that median time from ED triage to whole blood lactate results is 172 minutes.⁵

EtCO2 Monitoring Correlates with Blood Lactate^2,3

Because patients compensate for tissue hypoperfusion induced acidosis with respiratory alkalosis, reduced EtCO2 can serve as a surrogate marker of lactic acidosis.² EtCO2 has been demonstrated as a reliable method for identifying patients with acidosis in emergency department patients suffering from multiple conditions, such as pediatric gastroenteritis, metabolic disturbances, and penetrating trauma.^9-11 Both McGIllicuddy et al. and Hunter et al. found the EtCO2 is associated with mortality and lactate levels in suspected sepsis patients.^2,3

Model demonstrating the relationship between severity of sepsis-induced acidosis and end-tidal carbon dioxide values.

Implementing a Pre-Hospital Sepsis Screening Program with Microstream™ Capnography

Integration of EtCO2 into sepsis screening protocols may improve success in early recognition of septic patients.¹ In July 2014, Orlando Regional Medical Center in Orange County, Florida implemented a pre- hospital sepsis screening protocol to facilitate the early identification of patients presenting with sepsis or severe sepsis.¹ Temperature, respiratory rate, heart rate, and EtCO2 were recorded in patients where EMS personnel suspected infection. In patients meeting all the screening protocol criteria (see Figure 3), a pre-arrival “Sepsis Alert” was initiated to facilitate rapid assessment and treatment. The “Sepsis Alert” provided a high sensitivity and specificity for patients with sepsis and severe sepsis (Table 1). Furthermore, of the recorded vital signs, EtCO2 had the highest sensitivity and specificity for predicting sepsis severe sepsis and mortality.

Table 1. Sensitivity and specificity of sepsis screening protocol for identifying patients with sepsis or severe sepsis

Criteria for a "Sepsis Alert”

Learn more about Microstream™ Capnography for EMS

References:
1. Hunter CL, Silvestri S, Ralls G, Stone A, Walker A, Papa L. A prehospital screening tool utilizing end-tidal carbon dioxide predicts sepsis and severe sepsis. The American journal of emergency medicine. 2016;34(5):813-819.
2. Hunter CL, Silvestri S, Dean M, Falk JL, Papa L. End-tidal carbon dioxide is associated with mortality and lactate in patients with suspected sepsis. The American journal of emergency medicine. 2013;31(1):64-71.
3. McGillicuddy DC, Tang A, Cataldo L, Gusev J, Shapiro NI. Evaluation of end-tidal carbon dioxide role in predicting elevated SOFA scores and lactic acidosis. Internal and emergency medicine. 2009;4(1):41-44.
4. Levy MM, Evans LE, Rhodes A. The Surviving Sepsis Campaign Bundle: 2018 Update. Critical care medicine. 2018;46(6):997-1000.
5. Goyal M, Pines JM, Drumheller BC, Gaieski DF. Point-of-care testing at triage decreases time to lactate level in septic patients. The Journal of emergency medicine. 2010;38(5):578-581.
6. Xu JY, Chen QH, Liu SQ, et al. The Effect of Early Goal-Directed Therapy on Outcome in Adult Severe Sepsis and Septic Shock Patients: A Meta-Analysis of Randomized Clinical Trials. Anesthesia and analgesia. 2016;123(2):371-381.
7. Yurkova I, Wolf L. Under-triage as a significant factor affecting transfer time between the emergency department and the intensive care unit. Journal of emergency nursing: JEN : official publication of the Emergency Department Nurses Association. 2011;37(5):491-496.
8. Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Critical care medicine. 2006;34(6):1589-1596.
9. Caputo ND, Fraser RM, Paliga A, et al. Nasal cannula end-tidal CO2 correlates with serum lactate levels and odds of operative intervention in penetrating trauma patients: a prospective cohort study. The journal of trauma and acute care surgery. 2012;73(5):1202-1207.
10. Hunter CL, Silvestri S, Ralls G, Bright S, Papa L. The sixth vital sign: prehospital end-tidal carbon dioxide predicts in-hospital mortality and metabolic disturbances. The American journal of emergency medicine. 2014;32(2):160-165.
11. Nagler J, Wright RO, Krauss B. End-tidal carbon dioxide as a measure of acidosis among children with gastroenteritis. Pediatrics. 2006;118(1):260-267.