The objective of this study was to investigate the relationship between exhaled end-tidal carbon dioxide (ETCO₂) and serum lactate via nasal capnography and to assess the ability of ETCO₂ to predict disease severity in children with suspected sepsis in a pediatric emergency department.

This prospective study included patients (≥ 30 days to ≤21 years of age) who presented with suspected sepsis to a tertiary pediatric emergency department. Pearson correlation coefficient was generated to measure the linear relationship between ETCO₂ and lactate. Receiver operating characteristic curves (ROC) were generated to assess the performance of ETCO₂ to predict a lactate ≥2 mmol/L and severe disease. Severe disease was defined as severe sepsis and septic shock.

From November 1, 2018 to March 31, 2020, 105 emergency department patients underwent evaluation for suspected sepsis. Sixty-nine patients met the inclusion criteria for the study. There was an inverse relationship between ETCO₂ and lactate with a correlation coefficient of −0.34 (p = .005). Severe disease had lower ETCO₂ (32 ± 6 mmHg, p < .001) and higher lactate (3.3 ± 1.7 mmol/L, p < .001). The area under the curve (AUC) for ETCO₂ to predict severe disease was 0.75 (95% CI 0.63, 0.86). An ETCO₂ cut off point of 30 mmHg correlated with a sensitivity of 93% and specificity of 32%.

We observed a significant inverse relationship between ETCO2 and lactate in children presenting with suspected sepsis. A lower ETCO2 was predictive of severe disease.