Department of Critical Care, Clinica Luganese Moncucco, Lugano, Ticino, Switzerland.
Service of Anesthesiology, Ospedale Regionale di Bellinzona e Valli, Bellinzona, Ticino, Switzerland.
PLoS One. 2022 Jun 2;17(6):e0269024. doi: 10.1371/journal.pone.0269024. eCollection 2022.
Nasogastric tube (NGT) placement is a procedure commonly performed in mechanically ventilated (MV) patients. Chest X-Ray is the diagnostic gold-standard to confirm its correct placement, with the downsides of requiring MV patients' mobilization and of intrinsic actinic risk. Other potential methods to confirm NGT placement have shown lower accuracy compared to chest X-ray; end-tidal CO2 (ETCO2) and pH analysis have already been singularly investigated as an alternative to the gold standard. Aim of this study was to determine threshold values in ETCO2 and pH measurement at which correct NGT positioning can be confirmed with the highest accuracy.
MATERIALS & METHODS: This was a prospective, multicenter, observational trial; a continuous cohort of eligible patients was allocated with site into two arms. Patients underwent general anesthesia, orotracheal intubation and MV; in the first and second group we respectively assessed the difference between tracheal and esophageal ETCO2 and between esophageal and gastric pH values.
From November 2020 to March 2021, 85 consecutive patients were enrolled: 40 in the ETCO2 group and 45 in the pH group. The ETCO2 ROC analysis for predicting NGT tracheal misplacement demonstrated an optimal ETCO2 cutoff value of 25.5 mmHg, with both sensitivity and specificity reaching 1.0 (AUC 1.0, p < 0.001). The pH ROC analysis for predicting NGT correct gastric placement resulted in an optimal pH cutoff value of 4.25, with mild diagnostic accuracy (AUC 0.79, p < 0.001).
In patients receiving MV, ETCO2 and pH measurements respectively identified incorrect and correct NGT placement, allowing the identification of threshold values potentially able to improve correct NGT positioning.
NCT03934515 (www.clinicaltrials.gov).
经鼻胃管（NGT）置管是机械通气（MV）患者中常见的操作。胸部 X 光片是确认其正确位置的诊断金标准，但需要 MV 患者移动和固有辐射风险。其他可能用于确认 NGT 位置的方法与胸部 X 光片相比准确性较低；呼气末二氧化碳（ETCO2）和 pH 值分析已被单独研究作为金标准的替代方法。本研究的目的是确定 ETCO2 和 pH 值测量中的阈值，在这些阈值下可以以最高的准确性确认正确的 NGT 定位。
这是一项前瞻性、多中心、观察性试验；合格患者的连续队列按地点分配到两组。患者接受全身麻醉、经口气管插管和 MV；在第一组和第二组中，我们分别评估了气管和食管 ETCO2 之间以及食管和胃 pH 值之间的差异。
从 2020 年 11 月至 2021 年 3 月，共纳入 85 例连续患者：40 例在 ETCO2 组，45 例在 pH 组。用于预测 NGT 气管错位的 ETCO2 ROC 分析显示，ETCO2 的最佳截断值为 25.5mmHg，敏感性和特异性均为 1.0（AUC 为 1.0，p < 0.001）。用于预测 NGT 正确胃内放置的 pH ROC 分析得出 pH 的最佳截断值为 4.25，具有轻度诊断准确性（AUC 为 0.79，p < 0.001）。
在接受 MV 的患者中，ETCO2 和 pH 值测量分别识别出不正确和正确的 NGT 放置，允许确定潜在能够改善正确 NGT 定位的阈值。
NCT03934515（www.clinicaltrials.gov）。
