Authors (including presenting author) :
Kwan WY(1), Luk C(2), Lam YL(2), Mak KH(2), Mok CP(1), Poon KY(1), Yeung KH(1)
Affiliation :
(1)Accident and Emergency Department, Tuen Mun Hospital, (2)Accident and Emergency Department, Tin Shui Wai Hospital
Introduction :
Diabetic Ketoacidosis (DKA) is one of the potentially life-threatening emergencies among adult diabetic population, and yet difficult to be identified at triage due to non-specific clinical presentation and a lack of reliable screening tool. In spontaneous breathing patients, nasal capnography allows non-invasive and instantaneous measurement of end-tidal carbon dioxide (ETCO2) which may reflect acid-base status. Therefore, we conducted the first local study to explore the utility of ETCO2 measurement via nasal capnography in identifying adult DKA patients by triage nurses in A&E departments.
Objectives :
(1)To evaluate the correlations between venous blood gas parameters and ETCO2 measured via nasal capnography in adult diabetic patients (2)To characterize the overall performance of ETCO2 in predicting DKA by area under ROC curve (AUC) (3)To determine the sensitivities, specificities and likelihood ratios at different ETCO2 cut-offs
Methodology :
A cross-sectional, prospective observational study of adult diabetic patients who presented to the A&E departments of Tuen Mun Hospital and Tin Shui Wai Hospital between October 2019 and April 2020. Information on patient’s demographic data and triage information was recorded. Measurement of ETCO2 using nasal capnography and venous blood gas analysis were performed.
Result & Outcome :
184 patients were enrolled of which 17 had DKA. DKA patients had significantly lower median levels of ETCO2, pH, pCO2, HCO3 and base excess. ETCO2 significantly correlated with pCO2 (r=0.639), HCO3(r=0.690) and base excess(r=0.634). The AUC of ETCO2 was 0.977 (95%CI, 0.944 - 0.994). An ETCO2 cut point of ≤23mmHg had a sensitivity of 88.24% (95%CI, 63.6-98.5) and a specificity of 98.20% (95%CI, 94.8-99.6) in predicting DKA. To conclude, ETCO2 value demonstrates outstanding performance in predicting adult patients with or without DKA. Use of nasal capnography in conjunction with clinical assessment may enhance triage nursing assessment in A&E departments.
