Q; What is the "6 days rule" for enteral nutrition in very sick critically ill patients?

Answer:  In very sick critically ill patients, enteral nutrition can be started pre or post pyloric with "mucotrophic dose" at a rate of 10 to 30 mL/hour, and to leave it there for about six days and if situation allows start advancing towards the goal rate. This approach gives benefits like decrease residual volumes, less need of  prokinetic agents and better plasma glucose control beside protecting gastrointestinal mucosa. This approach is taken from famous EDEN trial which though failed to show any major difference in overall outcomes between full enteral feed versus nucotrophic feeding for six days (after which both groups were at full enteral feeding), but showed some minor benefits as said above.


References:

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

2. Needham DM, Dinglas VD, Morris PE, et al. Physical and cognitive performance of patients with acute lung injury 1 year after initial trophic versus full enteral feeding. EDEN trial follow-up. Am J Respir Crit Care Med 2013; 188:567.