Question 30

College Answer

a)

Minnesota tube (Sengstaken-Blakemore or gastro-oesophageal balloon tamponade device acceptable) for balloon tamponade of bleeding oesophageal varices.

b)

Intubate patient to protect airway and simplify insertion. Check balloon for leaks & lubricate tube.

Pass via nares (or mouth if severe coagulopathy present) and guide under laryngoscopic control into oesophagus, until 50cm inserted.

Slowly inflate gastric balloon: 250ml air.

Gently withdraw tube until resistance felt (~30-35cm) as balloon engages with gastro-oesophageal junction.

Aspirate both ports. Check volume of fresh blood: reducing?

If bleeding has ceased (~80%) then leave oesophageal balloon deflated. Apply traction to tubing (as below)

If bleeding from mouth or oesophageal aspiration port continues, then inflate oesophageal balloon with air to 25-30mmHg (max 40).

Deflate oesophageal balloon for 10 min every 2-hrs.

Apply traction to tubing by tying 500ml bag of fluid over pulley.

Check position on CXR: identify gastric balloon below diaphragm & radio-opaque marker along course.

Or any acceptable technique

c)

Oesophageal stricture

Recent oesophageal surgery

Hiatus hernia

Unknown cause of GI bleed

d)

Trauma to nose, pharynx, oesophagus

Incorrect placement or dislodgement of gastric balloon in pharynx or oesophagus (may result in acute upper airway obstruction if airway not secured)

Oesophageal tear or rupture Failure to control bleeding. Aspiration pneumonitis.

Secondary infection: pneumonia, sinus

Nasal or oral mucosal ulceration & necrosis from traction.

Discussion

In order to be specific: that image above is of a Minnesota tube, not  an SB tube (see the number of ports?). This question is essentially identical to Question 30 from the first paper of 2013 and Question 18.3  from the first paper of 2008.

b)

The sequence of insertion should be as follows:

1. Protect the airway.
   Ideally, the patient should be intubated.
   This prevents you from inserting the tube into the trachea accidentally, and prevents aspiration of pooling oesophageal blood or displaced gastric content.
2. Inspect the tube and check the balloons for leaks.
   LITFL also recommend to calculate the compliance of the balloon "by inflating the  balloon with incremental 100ml aliquots of air to maximal recommended volume (usually 250 -300ml for SBT, 450-500ml for Minnesota) and note the corresponding balloon pressure at each step". This is highly appealing to any person who enjoys graphs.
3. Lubricate the tube.
4. Position the patient sitting up to 45°
   This protects them from aspiration
5. Insert the tube into the mouth or nose.
   The college answer offers the nares as an option, but realistically everybody always uses the orogastric route because these patients are always coagulopathic and thrombocytopenic from their chronic liver disease. Moreover, the tube is huge and thick, with big balloons- they will shred the nasal mucosa on the way in regardless of how much lube you cake them in. The insertion should ideally be performed under direct laryngoscopy so that you can be sure you are in the oesophagus.
6. The tube should be advanced to 50cm.
   The college answer prescribes a depth of 50cm, which is consistent with the classical technique for insertion (Bauer et al, 1974). The alternative is to measure from mouth to angle of the jaw, then suprasternal notch and xiphisternum. LITFL authors recommend the latter method, acknowledging that humans vary in the length of their oesophagus.
7. Inflate the gastric balloon. Check position with a chest Xray.
   There seems to be some disagreement as to how much one might inflate. The college recommend 250ml; LITFL mention that the Minnesota tube should take 450-500ml. Locally, we are more cautions: we inflate with about 100ml and then check position with an AXR. If one has produced a compliance curve for their balloon, one may check the balloon pressure against their curve to see whether it has been inflated in the oesophagus (LITFL offer a 15mmHg increase in pressure as a rough guide: if the post-inserion pressure for a given volume is more than 15mmHg higher than the pre-insertion pressure, then the balloon needs to be repositioned as it is likely in the oesophagus. )
8. Withdraw the tube until resistance is felt (at 30-35cm)
   This is usually the depth to the gastro-oesophageal junction. Tension develops, which gives one the impression that the balloon is up against an obstacle of some sort. If one has not inflated with enough air there will be no resistance, and the balloon will come out of the mouth to the embarrassment of the operator. 
9. Aspirate the gastric and oesophageal ports.
   If there was vigorous bleeding, it should have stopped by balloon tension.
10. Decide whether or not to inflate the oesophageal balloon.
    If you already know where the varices are on the basis of a gastroscopy result, you may use your judgment (i.e. there is no point of inflating the oesophageal balloon for gastric varices). Otherwise, one is guided by blood loss.  If bleeding from oesophageal and gastric ports has ceased,  then you may leave oesophageal balloon deflated. Bauer et al (1974) recommend to irrigate the suction ports with warm saline, to assure oneself that the aspirate returns clear and that there is no new bleeding.
11. If appropriate, inflate the oesophageal balloon to 25-30 mmHg pressure.
    The maximum oesophageal pressure is 40mmHg. If the bleeding in the oesophagus has stopped, one should deflate the oesophageal balloon by 10mmHg every 2 hours.
12. Apply traction to the tubing
    The precise amount of traction is uncertain. Some centres specify 1kg, others 2kg. The college answer calls for a 500ml bag of fluid, suspended over a pulley.

Contraindications to SB tube insertion include the following:

• Unprotected airway
• Oesophageal rupture (eg. Boerhaave syndrome)
• Oesophageal stricture
• Uncertainty regarding the source of bleeding (how do you know it is not duodenal?)
• Well-controlled variceal bleeding

Complications of SB tube insertion and measures to prevent them:

	Preventative measure
Aspiration	Use only in intubated patients Sit the patient up to 45° Aspirate all gastric content before inflating the gastric balloon
Oesophageal rupture	Ensure both balloons completely deflated prior to insertion Avoid inflation of oesophageal balloon Ensure gastric balloon is correctly positioned during inflation
Gastric balloon migration; upper airway obstruction	Only use in intubated patients An older paper recommends the tube be fixed in position to the face mask of a standard football helmet
Oesophageal necrosis	Dont inflate the oesophageal balloon Avoid using this device for longer than 24-36 hrs Avoid using traction for prolonged periods Deflate the balloon regularly to check for rebleeding Monitor the gastric/oesophageal pressure carefully - keep it under 15mmHg