does it have any bearing on outcome in the icu or during the post - icu period ?
although not evidence based in any prospective , controlled , randomized clinical trials , it is unlikely that anyone would dispute that under - feeding eventually leads to death .
this parallels the lack of controlled studies on the use of parachutes when jumping out of aeroplanes at high altitude .
nevertheless , a short period of starvation appears to be a part of clinical treatment in many icus .
this is highlighted by a report from colleagues in the netherlands presented in this issue of critical care .
intensive care medicine is a comparatively young speciality , and within our arsenal of treatments the amount of evidence - based knowledge is often embarrassingly low .
an illustration of this is seen in the guidelines for the surviving sepsis campaign , in which the evidence for different treatment modalities was evaluated in a formalized way .
when we come to icu nutrition , there is little evidence at hand in terms of prospective , randomized , controlled clinical trials ; this was highlighted in recently published canadian guidelines .
. some authors even call it ' poisonous nutrition ' and ban it from use in the icu .
most investigators and authorities in the field would advocate enteral nutrition before parenteral , merely on the grounds that it is the natural way to feed and is cheaper .
the evidence in favour of enteral over parenteral nutrition , or the other way around , is weak ; furthermore , it is obsolete because it was generated more than 10 years ago , with obscure indications for parenteral nutrition and with no blood sugar control . in studies comparing enteral and parenteral nutrition in patients
whose attending physician is unsure regarding which modality will be optimal , the results demonstrate a very low feeding success rate with enteral nutrition and that complications are related to the duration of nutritional treatment , regardless of the mode of administration . in general terms it has repeatedly been shown that when patients are given only enteral nutrition , the success of feeding is below 70% .
successful feeding may be defined in terms of the percentage of prescribed calories , number of days with at least 80% of prescribed calories delivered , or any other measure .
the study from the netherlands presented in this issue adds further evidence to a number of publications that demonstrate that clinical practice is equivalent to delivering as little as 50% of the prescribed kilocalories .
does this make any difference ? probably , a very large study population would be required to demonstrate that patients do worse when they are administered only 50% of the prescribed dose of antibiotics . the safety margin for bacterial kill
when administrating antibiotics is such that reducing doses to half would require 500010,000 patients to show a difference in a prospective study . still no - one would advocate such a regimen .
however , the side effects of antibiotics create renal insufficiency , liver insufficiency and drug fever , and predispose to development of multi - resistant bacteria .
nevertheless , no - one would deliberately give only 50% of the prescribed dose , stating that it does not matter whether 50% or 100% of the dose is administered .
when it comes to nutrition , however , many of us do this . in the study presented in this issue
, the post hoc analysis shows that any action that reflects an interest in nutrition , such as placing the tube in any other position than the stomach , using some type of enhanced formula , or having a percutaneous feeding device , increases success rates with nutrition .
these specially treated patient groups were small , and findings in these groups should perhaps not be used as a basis for clinical recommendations , but it is clear that an enhanced interest in nutrition and delivery of nutrition will increase success rates .
so , the main reason for the systematic under - feeding that is practiced in icus is probably a lack of interest by the attending physician .
binnekade and coworkers   do not give any information on success rates of feeding in relation to outcome .
this is a difficult area , and studies that try to link nutritional practice to outcome must be designed carefully .
there are examples in the literature of investigators jumping to conclusions based on insufficient information .
nevertheless , in any patient in whom a huge energy deficit is built up , resulting in malnutrition , increased risk for complications can be predicted .
in addition , evaluation of nutritional protocols in terms of success rate , nutrition related complications and outcome must be encouraged .
systematic under - feeding of icu patients may be used as a marker of suboptimal care . wherever it is considered a human right not be hungry
, the burden of producing proper evidence should be imposed on anyone who suggests that half the feed is good enough .
 systematic undernutrition of intensive care unit patients is common and neglected . is this inevitable or 
 can better routines and protocols make a difference ? the necessity of feeding may be regarded as self - evident , but more evidence is obviously needed to strengthen this issue . in rich countries it should be a human right not to be hungry . 
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