Colorimetric capnography to ensure correct nasogastric tube position.

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.