Predicting diabetic ketoacidosis in children by measuring end-tidal CO2 via non-invasive nasal capnography

AIM: To determine if nasal capnography can be used as a screening tool to predict diabetic ketoacidosis (DKA) in children with Type 1 diabetes mellitus (T1DM) presenting to the emergency department. METHODS: Cross-sectional, prospective, observational study of children with T1DM who presented to the Emergency Department of Princess Margaret Hospital for Children, Western Australia, over a 12-month period from June 2003 to June 2004. Information on demographic data and T1DM was recorded. Nasal capnography, venous blood gases and urinary analysis were performed on patients. Data were analysed using chi(2) tests and receiver operating characteristic curve analysis. Sensitivities and specificities were calculated at different end-tidal carbon dioxide (ETCO(2)) levels to predict presence of DKA. RESULTS: Fifty-eight patients aged 1-18 years (mean 10.7, SD 4.7) were analysed. Thirty-three (57%) were male and 30 (52%) presented with new onset of T1DM. Of the 58 cases, 15 (26%) had DKA, and 11 of these were new T1DM patients. No patients with an ETCO(2) > 30 mmHg had DKA (sensitivity 1.0, specificity 0.86). Six patients with an ETCO(2) < 30 mmHg did not have DKA. CONCLUSIONS: Nasal capnography in conjunction with clinical assessment is predictive of DKA. Further research into this area with larger numbers could help validate ETCO(2) as a screening tool for DKA in the emergency department.