Flatus Tube Insertion for Bowel Decompression
Flatus tube insertion is primarily performed endoscopically under direct visualization after successful detorsion of sigmoid volvulus or for decompression of colonic obstruction, with the tube advanced past the point of obstruction and secured in place to maintain decompression. 1
Pre-Procedure Assessment
Before attempting flatus tube placement, confirm the absence of:
- Colonic perforation (absolute contraindication)
- Bowel ischemia (requires immediate surgery)
- Active peritonitis
Plain abdominal radiographs or CT imaging should be obtained if there is any suspicion of these complications 1. CT with intravenous contrast is particularly useful for assessing colonic ischemia 1.
Equipment Preparation
- Flexible endoscope (preferred over rigid sigmoidoscopy due to superior diagnostic performance and lower perforation rates) 1
- Flatus/decompression tube (typically 8F-12F caliber)
- Water-soluble lubricant
- Suction capability
Step-by-Step Insertion Technique
1. Endoscopic Approach (Primary Method)
The procedure should be performed with flexible endoscopy as first-line treatment 1:
- Position the patient in left lateral decubitus position
- Advance the flexible endoscope through the rectum toward the point of obstruction
- Identify the transition point(s) - typically two points are visualized in sigmoid volvulus 1
- Perform detorsion if treating volvulus by advancing past both transition points 1
- Assess mucosal viability endoscopically - this is mandatory to rule out ischemia 1
2. Flatus Tube Placement
After successful decompression/detorsion:
- Advance the flatus tube through or alongside the endoscope to the site beyond the obstruction
- The tube can be "lassoed" onto the side of the flexible endoscope using a snare wire technique for accurate placement under direct vision 2
- Position the tube tip past the point of obstruction or torsion
- Withdraw the endoscope while maintaining tube position
- Secure the tube externally to the patient's buttocks with tape
3. Confirmation and Securing
- Confirm adequate decompression by observing gas and stool passage through the tube
- Leave the tube in place to maintain reduction and allow continued colonic decompression 1
- The tube facilitates mechanical bowel preparation if needed 1
Post-Insertion Care
Immediate management:
- Connect tube to gravity drainage or intermittent suction
- Monitor output volume and character
- Assess for signs of perforation (acute abdominal pain, peritoneal signs, fever)
Common pitfall: The tube must be positioned past the transition point(s) - simply reaching the obstruction is insufficient for successful decompression 1.
Success Rates and Complications
Endoscopic decompression with flatus tube placement achieves success in 60-95% of sigmoid volvulus cases 1. The procedure carries approximately 4% morbidity and 3% mortality 1.
Critical warning: Flexible endoscopy is strongly preferred over rigid sigmoidoscopy, as rigid techniques can miss ischemia in up to 24% of cases 1.
Alternative Considerations
For colonic obstruction from malignancy where endoscopic access is limited, tube decompression can serve as a bridge to surgery with technical success rates of 80-100% and clinical success of 72.5-100% 3. However, perforation risk exists (0-10%) from pressure of the tube tip against the colonic wall 3.
After successful placement, definitive surgical intervention should be strongly considered during the index admission or soon thereafter, as recurrence rates reach 43-75% without surgery 1.