Nadler Opher A, Finkelstein Marsha J, Reid Samuel R
Pediatric Emergency Medicine, Legacy Emanuel Medical Center, Portland, OR, USA.
Pediatr Emerg Care. 2011 Oct;27(10):907-10. doi: 10.1097/PEC.0b013e3182302769.
The objective of the study was to determine whether serum bicarbonate (HCO₃) concentration can accurately predict venous pH in the evaluation of diabetic ketoacidosis (DKA).
A retrospective review of patients who presented to a children's hospital emergency department and received an International Classification of Diseases, Ninth Revision code related to DKA or diabetes mellitus was performed. To be eligible for inclusion and data abstraction, patients had blood sampled simultaneously for venous blood gas and metabolic panel. A linear regression model was created using pH (dependent variable) and HCO₃ (predictor). The diagnostic performance and accuracy of HCO₃ to discriminate abnormal pH were evaluated using receiver operating characteristic curve analysis.
Three hundred patients met the inclusion criteria. The linear relationship between pH and HCO₃ using the Pearson correlation coefficient was found to be R = 0.89 (confidence interval [CI], 0.83-0.95; R = 0.79). Receiver operating characteristic curve analysis that maximized sensitivity and specificity demonstrated that a HCO₃ 18.5 or less predicts pH less than 7.3 (area under the curve = 0.97; CI, 0.94-0.99; sensitivity, 93%; specificity, 91%), and a HCO₃ 10.5 or less predicts pH less than 7.1 (area under the curve = 0.97; CI, 0.95-0.99; sensitivity, 97%; specificity, 88%).
Serum bicarbonate accurately predicts abnormal venous pH in children with DKA. Venous pH determination may not be necessary for all patients being evaluated for DKA.
本研究的目的是确定在评估糖尿病酮症酸中毒（DKA）时，血清碳酸氢盐（HCO₃）浓度能否准确预测静脉血pH值。
对一家儿童医院急诊科收治的、被赋予与DKA或糖尿病相关的国际疾病分类第九版代码的患者进行回顾性研究。为符合纳入标准并进行数据提取，患者需同时采集血液用于静脉血气分析和代谢指标检测。使用pH值（因变量）和HCO₃（预测变量）建立线性回归模型。采用受试者工作特征曲线分析评估HCO₃区分异常pH值的诊断性能和准确性。
300名患者符合纳入标准。通过Pearson相关系数发现pH值与HCO₃之间的线性关系为R = 0.89（置信区间[CI]，0.83 - 0.95；R² = 0.79）。使敏感性和特异性最大化的受试者工作特征曲线分析表明，HCO₃≤18.5可预测pH值＜7.3（曲线下面积 = 0.97；CI，0.94 - 0.99；敏感性，93%；特异性，91%），HCO₃≤10.5可预测pH值＜7.1（曲线下面积 = 0.97；CI，0.95 - 0.99；敏感性，97%；特异性，88%）。
血清碳酸氢盐可准确预测DKA患儿的异常静脉血pH值。对于所有接受DKA评估的患者，可能无需测定静脉血pH值。
