The levels of evidence (I-IV) and grades of recommendations identifying the type of supporting evidence (A+, A, A-, B+, B, B-) are defined at the end of the "Major Recommendations" field.
The following evidence-based recommendations were ratified at the guideline development conference.
- Enteral Nutrition (EN) in preference to Standard Care (nothing by mouth [NPO]), Grade B+ recommendation
5 Level II randomized controlled trials (RCTs). Ratified by positive meta-analysis and validated evidence-based guideline (Algorithms for Critical Care Enteral and Parenteral Therapy [ACCEPT]).
- Early EN (<24 hours) in preference to delayed EN, Grade B recommendation
3 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- Parenteral Nutrition (PN) in preference to Standard Care (Intravenous [IV] Glucose), Grade B recommendation
5 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- Early EN (<24 hours) in preference to PN, Grade B recommendation
6 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- Early PN (<24 hours) in preference to delayed (>24 hours) EN, Grade B+ recommendation
5 Level II RCTs. Ratified by positive meta-analysis and validated evidence-based guideline (ACCEPT). The results of the meta-analysis supporting this evidence-based recommendation (EBR) have been published elsewhere.
- Post-pyloric feeding when gastric feeding not tolerated, Grade B recommendation
8 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- Use of prokinetics when gastric feeding not tolerated, Grade B recommendation
5 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- EN supplemented with PN if 80% of goals not met with EN alone (after attempts at postpyloric feeding and use of prokinetics) by 72 hours, Grade B recommendation
4 Level II RCTs. Ratified by validated evidence-based guideline (ACCEPT).
- PN with glutamine vs. standard PN, Grade B- recommendation
4 Level II RCTs. Ratified by meta-analysis, heterogeneity present.
Glutamine may be beneficial in select patients. To identify which patients may benefit, each constituent RCT should be reviewed and clinical judgement should be exercised.
- Management of diarrhoea, Grade B recommendation
Ratified by validated evidence-based guideline (ACCEPT).
- Gastric residual values and tolerance, Level B evidence
Ratified by validated evidence-based guideline (ACCEPT).
Definitions:
Levels of Evidence
Level I: adequately powered* (low false +ve or false -ve), well conducted trials
Level II: small, under-powered (high false +ve and false -ve), well conducted trials
Level III**: non-randomised concurrent (contemporary) controls
Level IV**: non-randomised historical controls
Level V**: case series without controls
*The guideline developers defined power as a measure of the probability that a clinical trial will detect a treatment effect of a given magnitude (X), under the assumption that the treatment effect actually exists. To qualify as a Level I trial (adequately powered), the trialists must have established that it was plausible to assume that the treatment effect of magnitude X actually existed. Data from earlier trials is the best way to establish the plausibility of the magnitude of the expected treatment effect (Halpern, S.D., Karlawish, J.H., and Berlin, J.A. [2002]. The continuing unethical conduct of underpowered clinical trials. JAMA 288, 358-362).
** These Levels of Evidence were not considered at this guideline conference.
Grades of Recommendations
A+: More than one well conducted, adequately powered randomized controlled trial (RCT) with consistent results between studies (no heterogeneity), Level of Evidence Required: I
A: At least one well conducted, adequately powered RCT, Level of Evidence Required: I
A-: More than one well conducted, adequately powered RCT with inconsistent results (heterogeneity) between studies, Level of Evidence Required: I
B+: More than one well conducted RCT with consistent results between studies, Level of Evidence Required: II
B: At least one well conducted RCT, Level of Evidence Required: II
B-: More than one well conducted RCT with inconsistent results (heterogeneity) between studies, Level of Evidence Required: II
