Literature Summary
Major Literature
Casaer. Early versus Late Parenteral Nutrition in Critically Ill Adults. NEJM 2011;365:506-517
In a multicenter, randomized trial comparing early parenteral nutrition (within 48 hours of ICU admission) with late parenteral nutrition (within day 8 of ICU admission) to supplement inadequate enteral nutrition, in 4,640 critically ill patients, late parenteral nutrition was associated with multiple improvements, including shorter durations of ICU (3 days vs. 4 days;p=0.02) and hospital (14 vs. 16 days, p=0.004) stay, fewer ICU infections (22.8% vs. 26.2%, P=0.008), lower incidence of cholestasis (P<0.001), reduced requirement for ventilation for > 2 days (36.3% vs. 40.2%, P=0.006), less duration of renal-replacement therapy (7 vs. 10 days, P=0.008) and mean reduction in health care costs of £910 (P=0.04).
Doig et al performed a multicenter, randomized trial comparing standard care with early parenteral nutrition in 1,372 critically ill patients with relative contraindications to enteral nutrition remaining in ICU for > 2 days, and found no difference in 60 day mortality (standard care 22.8% vs. early PN 21.5%; risk difference −1.26%; 95% CI −6.6 to 4.1; P = 0.60). Early parenteral nutrition patients required fewer days of mechanical ventilation (7.73 versus 7.26, risk difference −0.47; 95% CI −0.82 to −0.11; P = 0.01), less muscle wasting based on subjective global assessment (0.43 versus 0.27; mean difference −0.16; 95% CI −0.28 to −0.038; P = 0.01) and less fat loss (0.44 versus 0.31; mean difference −0.13; 95% CI −0.25 to −0.01; P = 0.04). Day-60 quality of life (RAND-36 General Health Status) was statistically higher in the early PN group, which was not clinically meaningful. (45.5 versus 49.8; mean difference 4.3; 95% CI 0.95 to 7.58; P = 0.01).
Gastric vs. Postpyloric Feeds
2009 American Society for Parental and Enteral Nutrition (ASPEN) Guideline in the PICU
Post-pyloric compared with gastric feeds may improve caloric intake but insufficient data to recommend routine use of post-pyloric feeds
Post-pyloric feeding may be considered in children at high risk of aspiration who failed a trial of gastric feeding
2012 Surviving Sepsis Campaign Nutrition Guideline in the PICU
Enteral nutrition should be used who can tolerate it, parenteral feeding in those who cannot
Does not comment on gastric vs. post-pyloric
The most recent meta-analysis that includes trials from pediatric and adult population:
2013 Gastric vs. Post-pyloric Feeding on the Incidence of PNA in ICU (Jiyong) (attached)
Methods
15 randomized controlled trials included (13 adult and 2 pediatric trials)
Results
Post-pyloric group had PNA in 16% vs. 26% in the gastric group (statistically significant)
No difference between duodenal vs. jejunal tubes in post-pyloric group
No difference between 2 groups in aspiration
No difference between duodenal vs. jejunal tubes
No difference between 2 groups in vomiting
High quality trials showed lower rate of vomiting in post-pyloric group but no difference seen in low quality trials
Conclusion
Post-pyloric feed in the ICU associated with decreased PNA
No significant differences between jejunal vs. duodenal in PNA or aspiration
A deeper look at the 2 randomized studies only including the pediatric population from the above meta-analysis:
2004 Gastric vs. Small Bowel Feeding in Children Receiving Mechanical Ventilation (Meert) (attached)
Methods
32 pts in the gastric group, 30 in the small bowel group
Similar baseline characteristics
5pts in the small bowel group had tube displaced --> could not be replaced into the small bowel --> gastric tube was placed --> remained in the small bowel group (intention-to-treat)
Results
Gastric group achieved daily caloric goal less compared to small bowel group (statistically significant)
No difference between groups in vomiting, diarrhea, abd distension, feeding interruption
Mechanical ventilation days, ICU days, and hospital days longer in small bowel group (NOT statistically significant)
4 of 5 pts who died were in the small bowel group
No difference between groups in tracheal aspirates positive for pepsin (gastric enzyme)
No difference between pts with tubes proximal to 3rd duodenum vs. more distal tubes
Conclusion
Small bowel feeds enabled more calories to be delivered in PICU pts on vent
Small bowel feeds do not protect from aspiration, vomiting, diarrhea, abd distension, or interruption in feeds
2008 Use of Methylene Blue to Detect Subclinical Aspiration in Enterally Fed Intubated Pediatric Pts (Kamat) (attached)
Methods
27 pts in the NG group, 17 in the NJ group
Similar baseline characteristics
Aspiration detected by adding methylene blue to feeds and checking methylene blue in tracheal aspirate
Results
None of the pts in either group had aspiration PNA
No difference between groups in frequency of aspiration (via methylene blue test)
0 pts with subclinical aspiration in NG, 2 in post-pyloric
Time to initiation of feed longer in NJ group (median 6 vs. 24 hrs)
NG group achieved caloric goals earlier
Number of AXR required less in NG group (median 1 vs. 4 AXRs)
Conclusion
Placing post-pyloric tube delays feeding considerably and increases radiation exposure without the benefit of decreasing aspiration events
An interesting randomized study in the adult population NOT included in the above meta-analysis:
2012 Early NJ vs. NG Nutrition in Critical Illness (Davies)
Methods
17 medical/surgical ICUs in Autralia
181 mechanically ventilated adults with elevated gastric residual volumes (>150mL X1 or >500mL over 12 hrs) and receiving narcotic infusion (morphine, fent, meperidine) randomized to:
NJ feed
Continued NG feed
Results
No difference in amount of nutritional delivery
No difference in rates of VAP, vomiting, witnessed aspiration, diarrhea, or mortality
NJ was associated with more minor GI hemorrhage (GIB without drop in BP, increased HR, or decreased hgb)
Conclusion
Routine placement of NJ tube in pts with increased gastric residuals is NOT recommended
Bottom Line
Current pediatric guidelines do not recommend gastric vs. post-pyloric enteral feeds
Pediatric data suggests no increased risk of aspiration with gastric feeds
Combined adult and pediatric data suggests increased risk of PNA with gastric feeds
Pediatric data suggests post-pyloric feeds can achieve daily caloric goal more often than NG feeds in 1 study but but takes longer to achieve caloric goal in another study
Pediatric data suggests post-pyloric tube placement exposes pts to higher radiation than NG tube placement
Once post-pyloric tube placed, duodenal vs. jejunal does not seem to matter
Although the pediatric guideline suggests placing post-pyloric tube when a pt fails NG feeds, recent adult data suggests continuing with gastric feeds