As the case of a 77 year old man with septic shock evolves, the 8th installment of the NEJM’s Critical Care Challenge focuses on feeding critically unwell patients. The vexed question of when to start feeding and by what route has been debated by respondents worldwide, and series editors Simon Finfer and Jean-Louis Vincent have reviewed the evidence relating to nutrition in this context.
A well-nourished 77-year-old man whose medical history includes previous heavy alcohol intake has been admitted to the ICU after a Hartmann’s procedure for fecal peritonitis. He is in septic shock, mechanically ventilated and his arterial blood pressure is supported with a noradrenaline infusion. He is noted to have low-grade DIC and does not currently merit any specific treatment other than withholding previously prescribed heparin and repeating the laboratory tests in 8 to 12 hours.
At this point, the poll asked what strategy would you use to provide nutrition for this patient?
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A small majority of the respondents (53%) would have commenced enteral nutrition within 24 to 48 hours of ICU admission and would then initiate parenteral nutrition on day 7 if the caloric target was not being met. 30% of voters however would favour early parenteral nutrition, commencing it as soon as possible after the patient’s arrival in the ICU, switching to enteral nutrition “once bowel sounds return”.
In their recommendations, the series editors support the early commencement of enteral feeding on the basis of potential benefits to gut mucosal integrity and the some weak evidence of benefit, such as that seen in a metaanalysis of trials on early EN (within 24 hours) which demonstrated a significant reduction in mortality [OR = 0.34], but which was limited by the poor quality of included trials.
Where enteral nutrition is either contraindicated or not sufficiently tolerated to allow provision of full caloric requirements, the role of supplemental parenteral nutrition is controversial, and no significant benefit has been demonstrated in a number of trials. Indeed, as outlined in the accompanying review article, the EDEN trial (as well as a number of smaller RCTs) demonstrated no significant harm (or benefit) associated with underfeeding with “trophic feeding” protocols compared to full caloric replacement.
In the absence of strong evidence of the most appropriate time to initiate supplemental parenteral nutrition, the editors suggest that it may be appropriate to commence parenteral nutrtion if there is likely to be a significant delay to the establishement of trophic feeding either because of intolerance or surgical issues (the patient has, after all, been admitted post colectomy)
The associated review article can be found here.
