Diagnostic Accuracy of End-Tidal Carbon Dioxide for Assessing Diabetic Ketoacidosis: A Systematic Review and Meta-Analysis.

Abstract

<h4>Introduction</h4>Diabetic ketoacidosis (DKA) is one of the complications of diabetes mellitus that requires rapid and accurate diagnosis. End-tidal carbon dioxide (EtCO₂) has been used for diagnosing DKA, however, there is uncertainty about the predicting value of this tool. In the current systematic review and meta-analysis, we purposed to assess the predictive value of EtCO₂ in diagnosing DKA.<h4>Methods</h4>We conducted a comprehensive search in PubMed, Scopus, and Web of Science for relevant studies and after screening based on the inclusion criteria, we extracted data. DKA diagnosis in the included studies was based on a composite clinical reference standard, including arterial blood gas (ABG) analysis and ketone testing. We used the Joanna Briggs Institute (JBI) checklist for diagnostic test accuracy studies for quality appraisal. Meta-analysis was performed based on the methods of the Cochrane DTA Handbook using the MetaDTA: Diagnostic Test Accuracy Meta-Analysis v2.1.3.<h4>Results</h4>A total of 13 studies were included in the systematic review, eight of which were proceeding to meta-analysis. The pooled sensitivity and specificity of EtCO₂ for diagnosing DKA were 0.96 (95% confidence interval (CI): 0.85-0.93) and 0.88 (95% CI: 0.79-0.93), respectively. The pooled diagnostic odds ratio (DOR) was 211.07 (95% CI: 38.3- 1162.1). The positive and negative likelihood ratios were 8.27 (95% CI: 4.6-14.7) and 0.03 (95% CI: 0.009-0.18), respectively. The results of the quality appraisal of include studies indicated moderate to low risk of bias.<h4>Conclusions</h4>The findings of this systematic review and meta-analysis show the high sensitivity and specificity of EtCO₂ in diagnosing DKA, which indicates its potential as a reliable diagnostic tool in emergency settings. However, the overall quality of the included studies, which were assessed to have medium to high risk of bias, should be considered when using EtCO₂ in clinical practice. Further high-quality research is needed to confirm the diagnostic value of EtCO₂ in emergency settings.