May 4, 2016 | Josh Farkas
The most widely feared complication of placing a Blakemore tube is complete inflation of the gastric balloon while it is not in the stomach. If the gastric balloon is fully inflated anywhere outside the stomach (i.e. esophagus, trachea, bronchus, duodenum), this may cause visceral perforation.
Two cases of ultrasound-guided Blakemore placement
A patient required Blakemore tube placement due to refractory variceal hemorrhage. With continuous monitoring via transgastric ultrasonography, the Blakemore tube was advanced. The tube could be visualized entering the stomach. When the tube was advanced to a depth of 50 cm, the gastric balloon was inflated with 50ml of air. The balloon was well visualized by ultrasonography to be inflating within the stomach.
Since ultrasonography is not a validated tool to confirm placement in the stomach, an abdominal X-ray was also ordered and waiting at the bedside. A portable X-ray was obtained, which confirmed that the balloon was inflated below the diaphragm.
Abdominal ultrasonography was resumed following the X-ray, but at that point the Blakemore tube could no longer be seen within the stomach. Further evaluation revealed that the tube had been inadvertently withdrawn while positioning the patient after the X-ray. The tube was re-advanced to 50cm, at which point the balloon could again be visualized within the stomach. At this point, the balloon was fully inflated under direct ultrasonographic guidance.
This case demonstrates how the traditional approach to confirming location prior to inflation of the gastric balloon can fail. In practice, there is often a lot of blood and this can make it difficult to secure tubes. The use of real-time ultrasonography allowed us to recognize malposition of the Blakemore tube and immediately reposition it.
Subsequent to this case, I have repeated this technique once. The second case was ultrasonographically identical to the first, with excellent views of the stomach. It was performed solely under ultrasound guidance, since the patient was crashing and radiology was not immediately available.
Simple approach to ultrasound-guided Blakemore placement
(1) Image the stomach
The first step is finding a good window to view the stomach. The stomach will typically be mostly filled with blood, facilitating examination (blood is an excellent transmitter of ultrasound waves). The presence of air may block visualization from an anterior approach. However, it may be possible to visualize the stomach using a more lateral or posterior approach:
Once an adequate window is found, the contents of the stomach may be viewed by fanning the probe back and forth. The figure below shows a long-axis view of the stomach, but the probe could also be rotated 90 degrees to fan along a short-axis view of the stomach as well.
(2) Place the Blakemore tube to ~50 cm & confirm location in the stomach
While viewing the stomach, the Blakemore tube may be advanced to 50 cm, a depth at which it should enter the stomach. With careful attention to ultrasonography, the tube may be seen entering the stomach (the combination of blood and gastric juice creates small particles within the stomach, “ultrasonographic coffee grounds,” which get stirred up when the tube enters the stomach). The tube itself should be directly visualized within the stomach at this point (seen as either two parallel lines or a small circle, depending on whether it is viewed in a longitudinal or transverse orientation).
If there is any doubt about whether the tube is in the stomach, a small amount of air could be injected into the distal port of the tube. This should immediately generate ultrasonographic microbubbles in the stomach.
(3) Inflate the gastric balloon under direct vision.
At this point, 50 ml of air can be inflated gradually into the gastric balloon. This should be immediately visualized within the stomach. Under direct visualization, the gastric balloon may be fully inflated.
Lock et al., 1997
These authors utilized the method described above. Unfortunately it is unclear how many times this was performed.
These authors describe an alternative technique to confirm entry of the Blakemore tube into the stomach:
- The transducer is placed sagitally along the midline of the epigastrum and then tilted towards the patient’s left to visualize the gastroesophageal junction.
- The transducer is then rotated 90 degrees to obtain a transverse view of the gastroesophageal junction and aorta (adjacent image)
- The Blakemore tube should be seen passing through the gastroesophageal junction as it is advanced
However, they note that this view may be impossible to obtain in patients with obesity or ascites. This is not my preferred approach because it doesn’t allow direct visualization of the balloon inflating within the stomach, which is arguably the best way to avoid balloon misplacement.
Should this technique be used? There is little evidence to support it, mostly this post and Lock 1997. Given that Blakemore placement is a rare and emergent procedure, it is doubtful that high-level evidence (i.e. an RCT) will ever become available.
Currently, such decisions may be deferred to the judgment of the bedside clinician, depending on factors including the adequacy of gastric ultrasound views and operator proficiency with ultrasonography. If the Blakemore tube and balloon are unequivocally seen within the stomach, ultrasonography may facilitate tube placement in a smooth fashion within minutes. However, if there is any doubt about the quality or significance of ultrasonographic images, then confirmation with abdominal radiographs should be obtained.
- Inflation of the gastric balloon of a Blakemore tube anywhere other than the stomach may cause visceral perforation (e.g. esophagus, trachea, duodenum).
- These patients typically have a stomach filled with blood, which facilitates gastric ultrasonography.
- Ultrasonography may allow for visualization of the Blakemore tube and gastric balloon within the stomach. This can guide rapid tube placement, without interrupting the procedure for X-ray confirmation.
Read article here