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).