Stool Monitoring in the Neonatal Intensive Care Unit (NICU)
Routine stool monitoring for occult blood and reducing substances in the NICU is not recommended as there is no evidence that it predicts necrotizing enterocolitis (NEC) or decreases its rate or severity. 1
Current Evidence on Stool Monitoring
Lack of Utility for Routine Testing
- Studies show that routine stool screening tests (occult blood, reducing substances) are not useful as diagnostic or screening tools for NEC 1
- These tests have significant direct costs and potential unintended consequences:
- Cost of secondary tests
- Unnecessary restriction of nutritional intake
- Accumulation of distracting, useless data
- Demands on nursing time
- Challenges in maintaining quality control
Appropriate Monitoring Approaches
Instead of routine stool testing, the following monitoring approaches are recommended:
- Individualize monitoring requirements for vital signs and observations based on the neonate's clinical condition 2
- Maintain fluid balance records and document concerning symptoms such as:
- Bilious or repetitive vomiting
- Abdominal distention that may indicate need for ultrasound exploration 2
Monitoring for Specific Conditions
Necrotizing Enterocolitis (NEC) Monitoring
For detection of NEC, point-of-care ultrasound (POCUS) is more valuable than stool monitoring:
- POCUS can detect signs of NEC when radiographs are inconclusive 2
- POCUS provides prognostic value by identifying:
- Free fluid
- Bowel wall thickness
- Pneumatosis intestinalis
- Portal venous gas
- Vascular perfusion 2
The International Neonatal Consortium's NEC subgroup recommends the "two out of three" model for diagnosis, which includes pneumatosis intestinalis or portal venous gas detected by abdominal X-rays and/or POCUS 2.
Infection Prevention and Monitoring
- Regular monitoring of bacterial colonization patterns is important, as abnormal flora can develop in the NICU 3
- C. perfringens in stool has been associated with gastrointestinal signs including:
- Flatulence
- Distended abdomen
- Foul-smelling stools
- Diarrhea
- Blood in stool 4
Recommended Approach to Neonatal Monitoring
Clinical observation for signs of feeding intolerance or GI distress:
- Increased episodes of apnea, desaturations, bradycardia
- Lethargy and temperature instability
- Feeding intolerance, emesis
- Bloody stools
- Abdominal distention and tenderness
- Abdominal wall discoloration 5
Targeted diagnostic testing when clinically indicated:
- Complete blood count with differential
- Blood culture
- Imaging studies (X-ray, ultrasound) 6
Avoid routine stool testing for occult blood or reducing substances 1
For urine collection and monitoring:
- Avoid adhesive bags
- Attempt clean-catch collection or dipstick testing 2
Special Considerations
- Premature infants are at higher risk for NEC and require more vigilant monitoring of feeding tolerance 5
- Infants on antibiotics may have altered gut colonization, potentially favoring opportunistic bacteria like C. perfringens 4
- Infants delivered by cesarean section may have different colonization patterns and increased risk of certain pathogens 4
Conclusion
The evidence strongly suggests moving away from routine stool testing in the NICU and toward a more targeted approach based on clinical signs and symptoms, with appropriate use of imaging modalities like POCUS when indicated. This approach is more cost-effective, reduces unnecessary interventions, and focuses nursing time on more valuable monitoring activities.