When assessing gastric residual volume, should the aspirated gastric fluid be returned to the stomach or discarded if the volume is small?

Should Aspirated Gastric Fluid Be Returned or Discarded?

Return small volumes of aspirated gastric fluid to the stomach rather than discarding them. This practice reduces the incidence and severity of delayed gastric emptying without increasing complications 1.

Evidence-Based Recommendation

The highest quality evidence directly addressing this question comes from a randomized controlled trial by Juve-Udina et al. (2009) involving 125 critically ill patients 1. This study demonstrated that:

• Returning gastric aspirates significantly reduced delayed gastric emptying episodes (p=0.001) compared to discarding
• No significant differences occurred in feeding complications, aspiration pneumonia, nausea/vomiting, or diarrhea between groups
• Mean gastric residual volumes were similar between return and discard groups (p=0.111)
• The only notable difference was in hyperglycemia rates, but this did not translate to clinically significant harm

Supporting Evidence and Consensus

A 2019 systematic review and meta-analysis of 4 RCTs (314 patients) confirmed these findings 2:

• No significant differences in 48-hour residual volumes between returning vs. discarding (MD = 8.89,95% CI: -11.97 to 29.74)
• No differences in potassium levels, gastric emptying delays, aspiration pneumonia, or gastrointestinal symptoms
• The authors concluded that returning aspirates does not increase complications

The 2021 Cochrane review further supports this approach, finding very uncertain evidence about whether discarding or returning aspirated gastric residual volume affects clinical outcomes 3. When evidence is equivocal, the safer clinical approach is to return the fluid to preserve electrolytes and gastric pH.

Clinical Rationale

Why Return Small Volumes:

• Preserves electrolytes (particularly potassium, chloride, and hydrogen ions)
• Maintains gastric pH balance and digestive enzyme content
• Reduces metabolic complications from fluid and electrolyte losses
• No increased risk of aspiration, pneumonia, or feeding intolerance

When Volume is Small:

The ESPEN ICU guideline suggests that enteral feeding should only be delayed when gastric residual volume exceeds 500 mL per 6 hours 4. Volumes below this threshold should be returned to the stomach and feeding continued.

Practical Algorithm

1. Aspirate and measure gastric residual volume per your institution's protocol
2. If volume < 500 mL per 6 hours: Return the aspirate to the stomach and continue feeding
3. If volume ≥ 500 mL per 6 hours:
   • Hold feeding temporarily
   • Consider prokinetic therapy (erythromycin 100-250 mg IV three times daily as first-line) 4
   • Reassess in 4-6 hours
4. Always return the aspirate unless there are specific contraindications (e.g., feculent material, suspected obstruction)

Important Caveats

• This recommendation applies to liquid gastric aspirates during routine residual volume assessment
• Do not return aspirates containing solid/particulate matter, blood, or feculent material
• The evidence base is primarily from critically ill adults receiving enteral nutrition
• Gastric residual volume monitoring itself has uncertain benefit 3, but when performed, returning aspirates is the preferred approach

The evidence consistently shows that returning small volumes of gastric aspirate is safe and may reduce feeding complications compared to routine discarding 1, 2.