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Radiology of the Endotracheal and Nasogastric tubes
Radiology of the Endotracheal and Nasogastric tubes
Ravi Ramakantan
Ravi Ramakantan
The Endotracheal Tube
The Endotracheal Tube
Extension
Extension
Flexion
Flexion
The length of the effective 'air passage" between the superior thyroid notch and the suprasternal notch varies significantly between Extension and Flexion
The length of the effective 'air passage" between the superior thyroid notch and the suprasternal notch varies significantly between Extension and Flexion
Neutral
Neutral
Flexion
Flexion
Extension
Extension
In the image above, the distance between the carina and the top of the rubber band - representing the air passage length - dramatically changes between the neutral, flexion and extension positions. However, the distance between the tip of the endotracheal tube and the point of proximal fixity (corresponding to the fixation point at the lips or the nose) of the endotracheal tube does not change (see the white double bracket on the left of each image remains of the same length. This effectively shows that, in essence, it is not the endotracheal tube per se that moves; but, its movement is relative to the length of the air passage.).
In the image above, the distance between the carina and the top of the rubber band - representing the air passage length - dramatically changes between the neutral, flexion and extension positions. However, the distance between the tip of the endotracheal tube and the point of proximal fixity (corresponding to the fixation point at the lips or the nose) of the endotracheal tube does not change (see the white double bracket on the left of each image remains of the same length. This effectively shows that, in essence, it is not the endotracheal tube per se that moves; but, its movement is relative to the length of the air passage.).
Therefore it is logical that:
Therefore it is logical that:
In extension, as the length of the air passage increases , the tip of the endotracheal tube moves away from the carina.
In extension, as the length of the air passage increases , the tip of the endotracheal tube moves away from the carina.
On flexion, as the length of the air passage decreases and the tip of the endotracheal tube moves towards the carina.
On flexion, as the length of the air passage decreases and the tip of the endotracheal tube moves towards the carina.
The Nasogastric tube
The Nasogastric tube
Irrespective of the brand, the proximal-most side-hole is the only side-hole on the radio-opaque marker line
Irrespective of the brand, the proximal-most side-hole is the only side-hole on the radio-opaque marker line
(Above) With the proximal side-hole proximal to the LES, aspiration fills the lower esophagus and spill into the trachea - the nasogastric tube acts like a stent.
(Above) With the proximal side-hole proximal to the LES, aspiration fills the lower esophagus and spill into the trachea - the nasogastric tube acts like a stent.
(Below) With the proximal side-hole distal to the LES, aspiration does NOT fill the lower esophagus
(Below) With the proximal side-hole distal to the LES, aspiration does NOT fill the lower esophagus
(Left) With the proximal side-hole distal to the LES, injection does not fill the esophagus
(Left) With the proximal side-hole distal to the LES, injection does not fill the esophagus
(Right) With the proximal side-hole proximal to the LES, injection fills the esophagus
(Right) With the proximal side-hole proximal to the LES, injection fills the esophagus
Pediatric enteral feeding tube (above), The tip should be beyond the duodeno-jejunal flexure (all side holes should be well beyond the pyloric sphincter) . Normal infant feeding tube (below). Same rules as an NGT
Pediatric enteral feeding tube (above), The tip should be beyond the duodeno-jejunal flexure (all side holes should be well beyond the pyloric sphincter) . Normal infant feeding tube (below). Same rules as an NGT
Thus: The only correct position of the nasogastric tube is when the proximal most side hole (the only one that is seen on the radiograph) is well distal to the lower esophageal sphincter with the tip of the nasogastric tube within the stomach - preferably in the distal body.
Thus: The only correct position of the nasogastric tube is when the proximal most side hole (the only one that is seen on the radiograph) is well distal to the lower esophageal sphincter with the tip of the nasogastric tube within the stomach - preferably in the distal body.
A video of such a lecture is here.
A video of such a lecture is here.
ET too far distal . Neck in extension
ET too far distal . Neck in extension
ET too far proximal . Neck in flexion
ET too far proximal . Neck in flexion
The LES is usually about a centimeter distal to the level of the diaphragm. In all three examples above the NGT is far too proximally placed
The LES is usually about a centimeter distal to the level of the diaphragm. In all three examples above the NGT is far too proximally placed
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