How to check Gastric Residual Volume (GRV) in a patient being fed through a nasogastric tube?

How to Check Gastric Residual Volume (GRV) in Patients with Nasogastric Tube Feeding

Routine GRV monitoring is not necessary for all tube-fed patients and should be limited to those with feeding intolerance or at high risk for aspiration. 1, 2

When to Check GRV

• GRV monitoring should be performed during initial stabilization of tube feeding regimen (typically every 4-6 hours) 3
• GRV should be checked in patients with signs of feeding intolerance such as:
  • Vomiting or regurgitation 3, 2
  • Abdominal distension or pain 2
  • Absence of bowel sounds 1, 2
• High-risk patients who benefit from GRV monitoring include:
  • Patients with impaired consciousness 2
  • Patients with neurological disorders affecting swallowing 2
  • Patients in prone position 2
  • Post-surgical patients 1
  • Patients with hemodynamic instability 1

Procedure for Checking GRV

1. Position the patient at a 30-45° angle (semi-recumbent) to reduce aspiration risk 1, 3
2. Use a small diameter nasogastric tube (8 French) for patients at risk of aspiration 1
3. Verify proper tube placement before checking GRV (via x-ray, aspiration of gastric content, or pH measurement) 1, 4
4. Use a 60 mL syringe to aspirate gastric contents slowly 5, 6
5. Record the volume of aspirated contents 5, 6
6. Return the aspirated contents to the stomach unless contraindicated (volume >500 mL) to prevent electrolyte imbalances and loss of nutrients 1, 3

GRV Thresholds and Management

• Continue enteral feeding if GRV is <500 mL/6 hours 1, 3
• If GRV exceeds 500 mL/6 hours:
  • Temporarily hold enteral feeding 1, 2
  • Perform abdominal examination to rule out acute abdominal complications 2
  • Consider prokinetic agents (e.g., erythromycin) 1, 2
  • Reassess in 2-4 hours 3
• If persistent high GRV despite prokinetics:
  • Consider post-pyloric feeding tube placement 2
  • Evaluate for mechanical obstruction or ileus 1

Alternative Assessment Methods

• Ultrasound assessment of gastric antrum is more reliable than gastric suctioning for evaluating residual volume 7
• Refractometry and Brix value measurement can help distinguish between retained formula and gastric secretions 5, 6

Important Considerations

• The correlation between GRV and aspiration pneumonia is weak 1, 8
• Routine GRV monitoring may lead to unnecessary interruptions in nutritional support 8, 9
• Maintaining patient in semi-recumbent position (30-45° angle) during and after feeding reduces aspiration risk 1, 3
• For surgical patients or those in shock, more frequent GRV monitoring may be warranted 1

Special Patient Populations

• For patients with severe gastroparesis, consider post-pyloric (jejunal) feeding 3
• In stroke patients, dysphagia therapy should start early regardless of tube feeding status 1
• For patients with high aspiration risk, consider thickened liquids after appropriate swallowing assessment 1