In these groups parenteral nutrition is often used, either to supplement or replace the enteral route. Parenteral nutrition delivers nutrients but does not maintain gut integrity.
This paper considered whether in patients not meeting their nutritional requirements through enteral nutrition, parenteral nutrition should be used in the first week of treatment.
The results were of interest: Rates of infection were lower in the late initiation group. Do you think this is related to sugar control, and how would a more liberal BM target (as is now standard care) potentially alter the results? Or do you think that the lower rate of infection is due to some (unexplained) immunosuppression caused by PN? How could you support the latter view by the observed differences in CRP?
Why were the benefits of late initiation so much greater in those in whom no EN was given (i.e. surgical contraindication)? Is there something different about this group? Is it the removal of trophic feeding? Is it that PN is in itself harmful, and that this subgroup represented those with the greatest ‘dose’ of PN (i.e. all their calories were delivered via this route)? Or is it something else?
I look forward to seeing what you think about these points or anything else by your comments below.
* As far as nutrients go this is often taken as read, but I do sometimes wonder if this is another example of the (outdated) critical care practice of ‘normalising’ everything – illness seems to cause a reduction in appetite - could this be protective to survival? Does the maintenance of gut integrity have such a benefit it overshadows the ‘harm’ of providing nutrition? I wouldn’t make this argument in an exam however!