How do you perform a hydrostatic (enema) reduction of intussusception in a hemodynamically stable patient without perforation, peritonitis, severe abdominal distension, or a known pathological lead point?

Hydrostatic Reduction of Intussusception: Technical Procedure

Hydrostatic reduction under ultrasound guidance using normal saline is the preferred non-operative technique for pediatric intussusception, with success rates of 82-91% when performed in hemodynamically stable patients without peritonitis or perforation. 1, 2, 3

Pre-Procedure Requirements

Patient Selection Criteria:

• Hemodynamically stable after fluid resuscitation 1, 4
• No signs of peritonitis (no guarding, rigidity, or rebound tenderness) 1
• No radiological evidence of perforation (no pneumoperitoneum) 1
• No clinical signs of bowel ischemia (no markedly elevated lactate, severe continuous pain) 1
• Symptom duration ideally <48 hours, as delays beyond this significantly increase mortality 1, 5

Equipment Setup:

• Real-time ultrasound machine with high-frequency transducer 6, 7, 3
• Normal saline (room temperature or warmed) 6, 7, 3
• Rectal catheter (Foley catheter or specialized enema catheter) 6, 7
• Saline bag elevated 1 meter above the patient 6, 3
• Resuscitation equipment immediately available 2

Step-by-Step Technique

Patient Positioning:

• Place patient supine on examination table 6, 7
• Mild sedation and analgesia may be administered for comfort 2

Catheter Insertion:

• Insert rectal catheter gently into the rectum 6, 7
• Secure catheter in place (tape buttocks together or inflate Foley balloon if used) 6, 3

Ultrasound Monitoring:

• Position ultrasound transducer over the intussusception mass (typically right upper quadrant near hepatic flexure in 90% of cases) 7
• Maintain continuous real-time visualization throughout the procedure 3

Saline Administration:

• Begin gravity-fed normal saline flow through rectal catheter 6, 7, 3
• Maintain hydrostatic pressure by keeping saline reservoir 1 meter above patient 3
• No time limit should be imposed on the procedure duration - average successful reduction takes 14-22 minutes 6, 7
• Apply steady, continuous pressure rather than intermittent boluses 3

Definitive Criteria for Successful Reduction

Ultrasound Findings (Primary Indicators):

• Complete disappearance of the "target sign" or "pseudokidney sign" 3
• Visualization of the ileocecal valve in its normal position 3
• Direct observation of saline reflux into the terminal ileum 6, 3
• Fluid filling of small bowel loops proximal to the ileocecal valve 3

Clinical Findings (Secondary Indicators):

• Dramatic improvement in patient's clinical condition (decreased pain, improved activity) 6
• Palpable mass disappears on abdominal examination 6

Management of Partial or Failed Reduction

Partial Reduction:

• If reduction is incomplete but patient remains stable, a second attempt may be performed after a brief rest period 6
• Three patients in one series achieved complete reduction on second attempt 6

Failed Reduction:

• Proceed immediately to surgical exploration without further delay 1, 5
• Failure occurs in 9-18% of cases 6, 3
• Underlying pathological lead points (lymphoma, duplication cysts, Meckel's diverticulum) are found in some failed cases 6

Post-Reduction Monitoring

Mandatory Observation Period:

• Close monitoring for at least 24 hours after successful reduction to detect early recurrence 1, 5
• Recurrence occurs in 0.1-0.3% of cases, with highest risk in first 10 days 4

Critical Pitfalls to Avoid

Do Not Attempt Hydrostatic Reduction When:

• Signs of peritonitis are present 1
• Hemodynamic instability persists despite resuscitation 1
• Pneumoperitoneum is visible on imaging 1
• Patient is an adult (86-93% have pathological lead points requiring surgical exploration) 1, 5

Technical Errors:

• Do not use excessive pressure that could cause perforation 2, 8
• Do not declare success based solely on clinical improvement without ultrasound confirmation of complete reduction 3
• Do not delay surgical consultation if reduction fails 1, 5

Comparative Success Rates

Pneumatic reduction has higher success rates (61%) compared to hydrostatic reduction (44%) in direct comparison studies, though both are safe when performed by experienced operators. 8 However, ultrasound-guided hydrostatic reduction avoids radiation exposure entirely and provides superior real-time visualization of the reduction process, making it the preferred method in many institutions. 2, 3