Confirming gastric tube placement in neurocritical patients using the combined effects of end-tidal CO2 and pH testing: A prospective diagnostic study

Objective: To assess the predictive effects of end-tidal carbon dioxide partial pressure (PETCO2) in combination with pH measurement in confirming gastric tube placement in neurologically critical patients. Methods: This study included 105 patients with gastric tubes placed in the neurological intensive care unit of Henan Provincial People's Hospital between November 2023 and April 2024. By employing X-ray as a gold standard, we compared the predictive value of PETCO2, pH testing, or PETCO2 in combination with pH measurement on the position of the tubes. Results: Receiver operating characteristic curve analysis of the three methods revealed varying diagnostic efficiencies. The PETCO2 method exhibited low performance, with an area under the curve (AUC) of 0.714, sensitivity of 42.9 %, specificity of 100 %, positive predictive value (PPV) of 100 %, and negative predictive value (NPV) of 96.1 %. In contrast, the pH method demonstrated better diagnostic capability, with an AUC of 0.821, sensitivity of 71.4 %, specificity of 92.9 %, PPV of 41.7 %, and NPV of 97.8 %. PETCO2 in combination with pH method showed the highest efficiency, achieving an AUC of 0.964, sensitivity of 100 %, specificity of 92.9 %, PPV of 50%, and NPV of 100 %. Conclusion: Using PETCO2 combined with pH measurement to confirm gastric tube placement demonstrated high accuracy and reliability, consistent with X-ray results. This combined approach offers a reliable, non-invasive alternative to X-ray for confirming gastric tube placement in neurologically critical patients. Trial Registration: Chinese Clinical Trial Registry (Registration No. ChiCTR2300078001).