There are several ways of confirming placement, but unfortunately almost all are fallible. Thus, a combination of techniques is generally used in the ED.

Vocalization

 

Auscultation

 

Aspiration

 

Radiography

 

CO2 Capnometry

VOCALIZATION

If the patient is unable to speak or has a newly hoarse voice, the tube has likely passed through the vocal cords and should be removed immediately. However, the absence of these symptoms does not exclude tracheal intubation and should not be relied upon as proof of esophageal placement. 25

AUSCULTATION

One of the most common techniques utilized to confirm NGT placement is auscultation. This is done by insufflating 30cc of air via a catheter-tipped (Toomey) syringe into the main lumen of the NGT and listening over the stomach for a rush of air or gurgling sounds. While the presence of such sounds is reassuring, it does not definitively prove gastric placement, as air insufflated into the lungs, mediastinum, or pleural space (as may occur with a malpositioned tube-- see the Complications section for further discussion) may also produce gurgling epigastric sounds. 26 , 27 , 28 , 29

ASPIRATION

When the NGT is connected to suction, the quality of the aspirate should be noted. Presence of gross amounts of bloods or coffee grounds (as seen in upper gastrointestinal hemorrhage) or feculent material (as seen in high-grade bowel obstruction) strongly suggests proper placement of the tube. However, the mere presence of fluid in the aspirate does not unequivocally prove the NGT terminates in the stomach, as esophageal or refluxed gastric contents may be aspirated as well. 29 The pH of the aspirate may be checked (it has been reported that 81% of properly placed NGTs have aspirate pH levels between 1-4 26 ); however, this is not definitive proof that the NGT is within the stomach.

RADIOGRAPHY

The gold standard for confirming proper NGT placement is the chest radiograph. Visualization of the tip of the tube beneath the diaphragm in the area of the stomach proves that the NGT is indeed in proper position. It has been argued that radiographs are not always necessary when other confirmation techniques are used 30 and the mandatory use of chest radiographs has been debated. 28 , 31 However, given the numerous case reports (see Complications section) of materials such as charcoal and tube feeds instilled directly into the lungs via improperly placed NGTs 26 , 27 , 28 , 32 , we recommend that a chest radiograph be obtained in all cases in which any type of fluid is to be infused through the tube.

Below is an example of a misplaced nasogastric tube, diagnosed by chest radiography.

CO2 CAPNOMETRY

Several studies have evaluated the use of CO 2 capnometry to detect inadvertent endotracheal placement of NGTs, with favorable results. 25 , 33 , 34   While this is a promising approach, these studies focused upon small-bore feeding tubes in ICU patients, and their results may not be applicable to ED patients with larger-bore NGTs.

 

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