use trophic feeds in intubated ARDS patients

This patient presented after an overdose of amitriptyline, but she aspirated during intubation and developed ARDS and shock. The clinical course suggests that she will need intubation and mechanical ventilation for at least a few days, being unable to feed herself or provide for her own nutrition. She has no signs of malnutrition. Numerous randomized controlled trials have helped delineate the risks and benefits of different nutritional strategies in critically ill patients. While observational studies hinted that earlier and more complete nutrition could improve outcomes, well-designed prospective trials have failed to demonstrate this. The ARDS Network EDEN trial demonstrated that trophic enteral feeds of 10 to 20 mL/h for the first 6 days (about 400 kcal/d) compared with goal enteral feedings (about 1,200 kcal/d) resulted in fewer GI intolerances (vomiting, regurgitation, abdominal distension, abdominal cramping) and similar short-term and long-term clinical outcomes.

Similarly, the randomized, blinded TARGET trial compared energy-dense enteral formula containing 1.5 kcal/mL with standard enteral formula containing 1 kcal/mL. Despite receiving 50% more calories (1,800 vs 1,200 kcal/d), the energy-dense group had similar 90-day mortality and other short-term clinical outcomes, including organ failure support, infectious complications, and lengths of stay as the group receiving fewer daily calories. Like the EDEN trial, patients fed with the energy-dense enteral formula experienced more vomiting and regurgitation despite receiving more promotility agents.

Viewed as a safety measure and means to prevent aspiration and ventilator-associated pneumonia, gastric residual volumes are often monitored in patients receiving enteral feedings. However, data supporting this practice are scant and suggest that gastric residual volume measurements are highly variable and not very predictive of impending emesis or regurgitation. The randomized NUTRIREA trial demonstrated that checking gastric residual volumes every 6 h and holding feeds for volumes above 250 mL did not reduce either the primary outcome of ventilator-associated pneumonia or secondary end points of GI intolerance. One caveat is that this trial was conducted in medical patients, and few surgical critically ill patients were enrolled, potentially limiting the generalizability of the results.

The NUTRIREA-2 trial investigated the role of parenteral and enteral nutrition in patients in shock. This randomized trial found that parenteral nutrition, instead of enteral nutrition, for the duration of the time the patient was receiving vasopressors resulted in less bowel ischemia and pseudo-obstruction, although rates were very low in both arms. Despite this, early parenteral nutrition failed to demonstrate any significant difference in clinical outcomes, including mortality, lengths of stay, or organ failure support.12345

Footnotes

  1. SEEK Questionnaires ↩

  2. National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network; Rice TW, Wheeler AP, Thompson BT, et al. Initial trophic vs full enteral feeding in patients with acute lung injury: the EDEN randomized trial. JAMA. 2012;307(8):795-803. PubMed ↩

  3. Reignier J, Boisramé-Helms J, Brisard L, et al; NUTRIREA-2 Trial Investigators; Clinical Research in Intensive Care and Sepsis (CRICS) group. Enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2). Lancet. 2018;391(10116):133-143. PubMed ↩

  4. Reignier J, Mercier E, Le Gouge A, et al; Clinical Research in Intensive Care and Sepsis (CRICS) Group. Effect of not monitoring residual gastric volume on risk of ventilator-associated pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized controlled trial. JAMA. 2013;309(3):249-256. PubMed ↩

  5. TARGET Investigators, for the ANZICS Clinical Trials Group; Chapman M, Peake SL, Bellomo R, et al. Energy-dense versus routine enteral nutrition in the critically ill. N Engl J Med. 2018;379(19):1823-1834. PubMed ↩