Capnography: An Accurate Method to Assess the Position of the Feeding Tube in a Porcine Model

Abstract

Objective To test the accuracy of capnography in the differential placement of feeding tubes into the trachea versus the oesophagus. Method Nineteen pigs were anesthetised, and feeding tubes were placed into their tracheas and oesophagi. A naïve examiner attached a capnography to the tube and evaluated the presence or absence of flow waveforms on the capnography. In the next step experiment, we gave 20 intentional oesophageal ventilations to the animals to create a distended stomach. The feeding tubes were reinserted, and examined by a naïve examiner by capnography. Results Capnography demonstrated continuous flow waveforms for the feeding tubes placed in the tracheas, but no waveforms were observed for those placed in the oesophagi. In the next step experiment, we found the same results. Conclusion Capnography can be used to accurately determine the placement of tracheal versus oesophageal feeding tubes based on the presence or absence of flow waveforms.