What gastric aspirate volume is a contraindication to enteral feeding?

Gastric Residual Volume Threshold for Enteral Feeding

A gastric residual volume (GRV) exceeding 200 ml is considered a contraindication to enteral feeding and should prompt a review of the feeding policy. 1

Understanding Gastric Residual Volume Monitoring

• GRV monitoring is a common practice to assess feeding tolerance and reduce the risk of aspiration pneumonia in patients receiving enteral nutrition 1
• High GRVs may indicate gastric dysmotility, which increases the risk of regurgitation and aspiration 2, 3
• In critically ill patients, GI dysmotility is common and can lead to feeding intolerance 2

Evidence-Based GRV Thresholds

• According to the Gut guidelines for enteral feeding in adult hospital patients, if gastric aspirates exceed 200 ml when checked every four hours, the feeding policy should be reviewed 1
• This 200 ml threshold is particularly important in patients with doubtful gastrointestinal motility 1
• More recent evidence suggests that in some non-surgical critically ill patients, routine GRV monitoring may not be necessary unless feeding intolerance is present 1, 4

Management Algorithm for High GRV

When GRV exceeds 200 ml:

1. Review feeding regimen:

   • Consider reducing the rate of feeding 5
   • Evaluate for transition from continuous to intermittent feeding when appropriate 1

2. Consider pharmacological interventions:

   • Prokinetic agents such as metoclopramide or erythromycin may improve gastric emptying 1, 6
   • Erythromycin (200 mg IV) has been shown to improve gastric emptying in critically ill patients with large volume gastric aspirates 6

3. Evaluate feeding route:

   • Consider post-pyloric feeding (jejunal) for patients with persistent high GRVs 5, 4
   • Small bowel feeding can bypass gastric emptying issues 5

Special Considerations

• Patients at high risk for aspiration (e.g., those with surgery, hemodynamic instability, or impaired consciousness) require more vigilant monitoring of GRVs 1, 4
• Position patients at 30° or more during feeding and for 30 minutes afterward to minimize aspiration risk 1
• Continuous pump feeding can reduce gastrointestinal discomfort but should not be given overnight in patients at risk for aspiration 1

Common Pitfalls and Caveats

• Relying solely on GRV measurements may lead to unnecessary interruptions in enteral nutrition, resulting in underfeeding 7
• Patients received only 64% of goal energy intake in one study, with interruptions averaging 5.23 hours per day 7
• Other signs of feeding intolerance should be monitored, including vomiting, abdominal distension, and reflux of feeds into the oral cavity 1
• The threshold of 200 ml applies to gastric feeding; jejunal feeding typically bypasses this concern 5

Conclusion for Clinical Practice

• Check GRV every four hours in patients with doubtful gastrointestinal motility 1
• If GRV exceeds 200 ml, review and potentially modify the feeding strategy 1
• Consider prokinetic agents and/or post-pyloric feeding for persistent high GRVs 5, 6
• Balance the risks of aspiration against the benefits of adequate nutritional support 2, 3