Colorimetric capnography to ensure correct nasogastric tube position

J Crit Care. 2009 Jun;24(2):231-5. doi: 10.1016/j.jcrc.2008.06.003. Epub 2008 Sep 11.


Purpose: We evaluate a procedure, combining colorimetric capnography with epigastric auscultation, to ensure nasogastric (NG) feeding tube correct position without any radiograph.

Methods: We first evaluated the accuracy of colorimetric capnography in detecting tracheal positioning in a control group of 100 mechanically ventilated patients. The procedure was thereafter evaluated in a study group including patients requiring an NG tube. The NG tube was first inserted 30 cm and connected to a colorimetric capnograph (first step). If the capnograph did not detect carbon dioxide, insertion was completed to a total distance of 50 cm. An epigastric auscultation after air insufflation and a second capnography (second step) were performed. A radiograph evaluated correct tube position.

Results: In the control group, colorimetric capnograph sensitivity to detect tracheal placement was 100%. In the study group, negative predictive value of first-step capnography to rule out tracheobronchial insertion was 100%. The association of a first-step negative capnography with a positive epigastric auscultation correctly identified all but one gastric insertions, yielding a sensitivity of 98.5% (95% confidence interval, 95.7-100). The positive predictive value of this association to detect gastric placement was 100%.

Conclusion: Colorimetric capnography combined with epigastric auscultation is safe and accurate in ensuring correct gastric tube insertion.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Auscultation*
  • Calorimetry, Indirect
  • Capnography / methods*
  • Female
  • Humans
  • Intubation, Gastrointestinal / methods*
  • Male
  • Middle Aged
  • Prospective Studies
  • Trachea*