Utilizing End-Tidal Carbon Dioxide to Diagnose Diabetic Ketoacidosis in Prehospital Patients with Hyperglycemia

Abstract

Background:Early identification of diabetic ketoacidosis (DKA) may improve clinical outcomes. Prior studies suggest exhaled end tidal carbon dioxide (ETCO2) provides a non-invasive, real-time method to screen for DKA in the emergency department (ED).Methods:This a retrospective cohort study among patients who activated Emergency Medical Services (EMS) during a one-year period. Initial out-of-hospital vital signs documented by EMS personnel, including ETCO2 and first recorded blood glucose level (BGL), as well as in-hospital records, including laboratory values and diagnosis, were collected. The main outcome was the association between ETCO2 and the diagnosis of DKA.Results:Of the 118 patients transported with hyperglycemia (defined by BGL >200), six (5%) were diagnosed with DKA. The mean level of ETCO2 in those without DKA was 35mmHg (95% CI, 33-38mmHg) compared to mean levels of 15mmHg (95% CI, 8-21mmHg) in those with DKA (P <.001). The Area Under the Receiver Operating Characteristics (ROC) Curve (AUC) for ETCO2 identifying DKA was 0.96 (95% CI, 0.92-1.00). The correlation coefficient between ETCO2 and serum bicarbonate (HCO3) was 0.436 (P <.001) and the correlation coefficient between ETCO2 and anion gap was -0.397 (P <.001).Conclusion:Among patients with hyperglycemia, prehospital levels of ETCO2 were significantly lower in patients with DKA compared to those without and were predictive of the diagnosis of DKA. Furthermore, out-of-hospital ETCO2 was significantly correlated with measures of metabolic acidosis.

Capnography as a tool for triaging and diagnosis of diabetic ketoacidosis in the emergency department: A prospective observational study

“…The positive and negative predictive values were 96.4% and 85.0% with an accuracy of 92.7%. The compelling predictive value of capnography in detecting diabetic ketoacidosis (DKA), as observed not only in this study but also in prior studies[ 5 6 7 8 9 10 ], strongly suggests the inclusion of end-tidal carbon dioxide (EtCO2) measurements in the diagnostic criteria for DKA.…”

“…While numerous studies have explored the association of metabolic acidosis with capnography, most have targeted the pediatric population or had small sample sizes. [ 8 9 10 11 ] The present study, in contrast, recruited all its participants from the adult population and had a comparatively large sample size. The study assessed three possible roles of EtCO 2 : (a) its role as a triage tool for excluding DKA; (b) as an additional diagnostic criterion for DKA; and (c) its role in monitoring the treatment (degree of acidosis).…”

Practical method in the diagnosis of diabetic ketoacidosis: end-tidal carbon dioxide

“…In our study, it was concluded that there was a significant correlation between EtCO2 and bicarbonate (P<0.05). Similarly, previous studies have reported a significant linear correlation between end-tidal CO2 and bicarbonate [20][21][22]. As low bicarbonate level explains the metabolic acidosis present in patients with DKA, the linear significant correlation found between EtCO2 and bicarbonate is another result supporting that EtCO2 measurement can be used for diagnostic purposes in these patients.…”

End‐tidal carbon dioxide measured at emergency department triage outperforms standard triage vital signs in predicting in‐hospital mortality and intensive care unit admission

“…[7][8][9][10][11] It has a significant association with lactate and anion gap elevation and has found to be an indicator of DKA in pediatric and adult populations. [12][13][14][15][16][17] Furthermore, numerous studies have shown ETCO 2 to have a strong association with acute disease severity and mortality in sepsis, trauma, and shock. 7,13,[18][19][20][21][22][23][24][25][26] Prior studies have explored the clinical utility of adding ETCO 2 to the initial triage assessment of patients.…”

“…It has been widely accepted as the criterion standard for confirming proper endotracheal tube placement and as a useful prognostic indicator of initial outcome of resuscitation in cardiopulmonary arrest 7–11 . It has a significant association with lactate and anion gap elevation and has found to be an indicator of DKA in pediatric and adult populations 12–17 . Furthermore, numerous studies have shown ETCO 2 to have a strong association with acute disease severity and mortality in sepsis, trauma, and shock 7,13,18–26 .…”