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Page 6 of 18 Tebala et al. Mini-invasive Surg 2018;2:32 I http://dx.doi.org/10.20517/2574-1225.2018.37

Nutritional supplements are mandatory in malnourished patients and preoperative enteral or parenteral
feeding should be considered in patients who are not meeting the nutritional requirements.

Bowel preparation
Mechanical bowel preparation (MBP) has always been one of the cornerstones of colorectal surgery and
lower gastrointestinal endoscopy, but it may be associated with dehydration and electrolyte imbalance,
in particular in high risk patients (advanced age, renal impairment, liver failure). A Cochrane systematic
review published in 2005 indicated that MBP does not prevent anastomotic complications and therefore
should be avoided [6,44] . Although it was clear that this review was poorly significant due to high heterogene-
ity, it was suggested that no patient scheduled for colorectal resectional surgery should have his/her bowel
prepared. A RCT trial published in 2010 and a new Cochrane review published in 2011 found that, although
bowel preparation would make no difference in colonic surgery, it may be beneficial - and hence used selec-
tively - in patients undergoing rectal surgery [45,46] . More recent studies seem to give contrasting results.

Two recent meta-analyses on this subject, one conducted in the USA and the other in Europe, propose a
[47]
totally different approach. Yost et al. from Massachusetts found that MBP associated with oral antibiotics
can reduce the risk of anastomotic leak, wound infection and postoperative sepsis, and facilitate the manipu-
[48]
lation of the bowel in laparoscopic surgery. On the contrary, the systematic review by Leenen et al. from
the Netherlands arrives to the conclusion that MBP does not decrease the incidence of leak, but admits that
the study is flawed by the small size of the sample and the heterogeneity of the studies reviewed. Already
in 2015 a retrospective study on prospectively collected outcome data from the National Surgical Quality
Improvement Program on 8442 patients showed that MBP almost halves the risk of anastomotic leak, ileus
[49]
and surgical site infection .

The different approach to this issue between the two sides of the ocean reflects in the official guidelines.
The 2012 guidelines of the European ERAS Society clearly state, that MBP should be avoided in colonic and
rectal surgery [6,18] . On the contrary, the 2017 ASCRS/SAGES guidelines advocate the use of MBP with oral
[23]
antibiotics . This difference can be explained, at least partially, by the fact that the US review took into
account more recent evidences, clearly not available 5 years before, but also by the different cultural, and
probably financial attitude. Although local guidelines must be developed and validated, it is undeniable
that at the moment this is still matter for debate and a definitive answer is yet to come. We feel that with
the current status of evidence the ultimate choice must stay with the consultant in charge, as some sur-
geons may feel more confident to operate on a completely empty and deflated bowel, mostly in laparoscopy,
whereas others do not see the presence of a non-prepared bowel as a limitation or increasing difficulty. The
role of oral antibiotics associated with MBP is gaining popularity after the studies of Alverdy and his team
[50]
[23]
in Chicago and the ERAS guidelines of the ASCRS/SAGES .
INTRAOPERATIVE STAGE
Intra and postoperative fluid therapy
The traditional liberal infusion of fluids during and after a major operation, either by open or laparoscopic
surgery, has been demonstrated to be one of the causes of prolonged postoperative ileus, probably due to
the tissue oedema or sodium excess, and other perioperative complications, therefore is has been suggested
to have a more restrictive fluid regimen [51,52] . The so called “goal-directed fluid therapy” has been consid-
ered as the first choice to correctly titrate the amount of fluids to be infused during and after a surgical
[53]
operation . Invasive and non-invasive monitoring systems have been used to utilize cardiac output as
a guide for fluid infusion [18,54] , but currently most teams prefer to adopt a more “empiric” system, with a
low volume of intraoperative infusions followed by free oral fluid in the immediate postoperative period,