Table 1 PICOS criteria for inclusion and exclusion of criteria
| Parameter | Inclusion criteria | Exclusion criteria |
|---|---|---|
| Population | Adult tube-fed critically ill patients | Partial EN |
| Intervention | Supplementation with pre, pro, or synbiotics | |
| Comparison | Placebo or nothing | |
| Outcome | Enteral feed volume, Time to reach full enteral nutrition, the prevalence of feed intolerance and related GI complications (diarrhea, distention, high residual volume) | |
| Study design | Randomized controlled trials | In vitro studies |