What do systematic reviews say?

Higher threshold (500 mL per six hours or greater) vs lower threshold (less than 500 mL per six hours) at time of aspiration

It is very uncertain whether higher threshold (500 mL per six hours or greater) changes mortality (at the end of compared with lower threshold (less than 500 mL per six hours) at time of aspiration (very low certainty).

• Monitoring of gastric residual volume during enteral nutrition 2021 · Cochrane Headline outcomes only
  RR 1.01 [0.74, 1.38]
  1 study · 322 participants
  Very low

Higher threshold (500 mL per six hours or greater) vs lower threshold (less than 500 mL per six hours) at time of aspiration

It is very uncertain whether higher threshold (500 mL per six hours or greater) changes pneumonia (until discontinued or up to 28 days) compared with lower threshold (less than 500 mL per six hours) at time of aspiration (very low certainty).

• Monitoring of gastric residual volume during enteral nutrition 2021 · Cochrane Headline outcomes only
  RR 1.03 [0.72, 1.46]
  1 study · 322 participants
  Very low

Higher threshold (500 mL per six hours or greater) vs lower threshold (less than 500 mL per six hours) at time of aspiration

• Monitoring of gastric residual volume during enteral nutrition 2021 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 322 participants
  Very low