Servicio de Aparato Digestivo, Hospital Universitari ParcTaulí. Institut d'Investigació i Innovació ParcTaulí, Barcelona, España. Departamento de Medicina. Universitat Autònoma de Barcelona, España.
Servicio de Aparato Digestivo, Hospital Universitari ParcTaulí. Institut d'Investigació i Innovació ParcTaulí, Barcelona, España. Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd). Instituto de Salud Carlos III, Madrid, España.
Emergencias. 2018;30(6):419-423.
The American College of Gastroenterology's 2016 clinical guidelines for treating lower gastrointestinal (GI) tract bleeding recommends evaluating of nasogastric tube aspiration and the ratio of blood urea nitrogen (BUN) to creatinine to differentiate upper from lower GI bleeds. However, the evidence base to support recommending these 2 diagnostic variables is low. This study aimed to evaluate the diagnostic utility of nasogastric tube aspiration and the BUN-to-creatinine ratio for distinguishing between upper and lower GI bleeding.
We conducted a systematic review of the literature to find studies reporting the diagnostic precision of the BUN-to-creatinine ratio and nasogastric aspiration in patients with GI bleeding without hematemesis.
The sensitivity of both methods is low for detecting upper GI bleeding. Both blood in the aspirate and an elevated BUN-to-creatinine ratio significantly increase the probability of finding an upper GI source. The positive likelihood ratio varies from positive 2 to 11. However, the sensitivity of both tests for a diagnosis of upper GI bleeding is very low (negative likelihood ratio of 0.6).
A negative result on either of the 2 diagnostic tests provides little useful information and does not firmly rule out an upper GI bleed. Nasogastric tube aspiration cannot be recommended for distinguishing between upper and lower GI bleeding. If the diagnosis is in doubt, endoscopic exploration of the upper GI tract is necessary.
美国胃肠病学院 2016 年治疗下胃肠道（GI）出血的临床指南建议评估鼻胃管抽吸和血尿素氮（BUN）与肌酐的比值，以区分上消化道和下消化道出血。然而，支持推荐这两个诊断变量的证据基础很低。本研究旨在评估鼻胃管抽吸和 BUN 与肌酐比值在区分上消化道和下消化道出血中的诊断效用。
我们对文献进行了系统回顾，以寻找报告 BUN 与肌酐比值和鼻胃抽吸在无呕血的 GI 出血患者中诊断精度的研究。
两种方法对上消化道出血的检测灵敏度均较低。抽吸物中的血液和升高的 BUN 与肌酐比值均显著增加发现上消化道来源的可能性。阳性似然比从阳性 2 到 11 不等。然而，两种测试对上消化道出血的诊断灵敏度都非常低（阴性似然比为 0.6）。
两种诊断测试中的任何一种结果呈阴性都提供的有用信息很少，不能确定是否存在上消化道出血。鼻胃管抽吸不能用于区分上消化道和下消化道出血。如果诊断有疑问，需要对上消化道进行内镜检查。
