The SA Journal Diabetes & Vascular Disease Vol 11 No 4 (November 2014)

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174 VOLUME 11 NUMBER 4 • NOVEMBER 2014
LEARNING FROM PRACTICE SA JOURNAL OF DIABETES & VASCULAR DISEASE
was first challenged in the 1980s and, as a result, many patients
were allowed clear fluids up until two hours prior to surgery. The
development of low osmolality carbohydrate drinks during the mid-
1990s opened up the opportunity of providing surgical patients
with a carbohydrate load two to three hours prior to anaesthesia.
In a comparative study of 14 patients undergoing colorectal surgery
Nygren et al. halved post-operative insulin resistance by the use of
such oral therapy.15 In a meta-analysis of three small prospective
studies, Ljungqvist’s team showed that such an approach can
lead to a reduction in hospital stay by about 20%.16 However, a
randomised study in Toronto of 26 patients undergoing coronary
artery bypass grafting and 12 patients having spinal surgery who
received oral carbohydrate supplements in the evening and two
hours before surgery showed no improvement in post-operative
insulin sensitivity. The patients who received the carbohydrate
supplements did, however, have lower blood glucose and higher
insulin levels than the traditionally fasted patients, although these
differences were not significant.17 In contrast, in a randomised
study from Brazil of gastrointestinal surgery, the addition of whey
protein to the carbohydrate drink appeared to have some added
value in terms of reduced inflammatory response and lesser insulin
resistance.18
The benefits of the ERAS approach to colorectal surgery have
been confirmed in several reports.19-21 It can extend for a significant
period after surgery.22 The role of pre-operative carbohydrate
supplementation has been assessed in a number of trials. The
mechanism by which it acts includes a reduction in catabolism of
fat and protein. This was shown in a study of 40 patients who
underwent an elective laparoscopic colectomy.23 However, most
studies on the role of pre-operative carbohydrate supplementation
have excluded diabetic patients. Clearly the concept of giving a
patient with inherent insulin resistance a carbohydrate load prior to
surgery is seen by many as ‘a step too far’. Indeed, in 2011 the Joint
British Diabetes Societies guideline on the management of adults
with diabetes undergoing surgery stated: ‘The Enhanced Recovery
Partnership Programme recommends the administration of high-
carbohydrate drinks prior to surgery. This may compromise blood
glucose control and is not recommended for people with insulin-
treated diabetes.’24
However, such a blanket recommendation against the use of
high-carbohydrate drinks prior to surgery requires re-evaluation.
Concerns about potential delays in gastric emptying among
patients with diabetes and, therefore, the re-introduction of the
risk of aspiration, appear unfounded. In a study of 25 patients
with type 2 diabetes Gustaffson et al. found no delay in gastric
emptying compared to healthy volunteers among patients given a
carbohydrate drink.25 In 2011, in a study from Poland, Jodlowski et
al. investigated the benefit of such drinks in 48 patients who were
to undergo elective colorectal surgery. Seven had type 2 diabetes.
Their conclusion was that a pre-operative oral carbohydrate load
was safe and well tolerated by them, although realistically this is
much too small a sample from which to make an inference. Overall
for both diabetic and non-diabetic patients it improved peri-
operative well-being, reduced hunger and reduced insulin blood
levels and insulin resistance on day two after surgery.26 This study
is of particular importance against the background of a report
from Michigan which investigated risk factors for anastamotic leak
following a colectomy amongst 5 123 patients.27 The occurrence of
a leak was not directly associated with the presence of diabetes but,
when it did happen, patients with diabetes had a four-fold mortality
of 26.3% compared with 6% for patients without diabetes. Other
evidence would suggest that the use of pre-operative carbohydrate
loading might reduce this difference in mortality subsequent to an
anastamotic leak.20,21 Unfortunately none of these studies included
any reference to whether these patients’ diabetes was well
controlled or whether they had complications of their diabetes.
The importance of insulin resistance as an independent factor
associated with prolonged hospital stay cannot be over emphasised.
The potential benefits of carbohydrate loading for patients with
diabetes have been shown in the field of cardiac surgery. A
randomised, double-blind, placebo-controlled trial in Germany
among 160 patients undergoing elective cardiac surgery, including
31 with non-insulin-treated type 2 diabetes, reported that blood
glucose levels, gastric fluid volume and insulin requirement did not
differ between groups. However, patients receiving a carbohydrate
load required less intra-operative inotropic support after initiation of
cardiopulmonary bypass weaning ( p < 0.05).28 This study provided
no details on how well controlled the patients were or the presence
of complications, but did specifically exclude patients with type 1
diabetes after initial recruitment.
Conclusions
Although patients with diabetes have been excluded from most
trials looking at the role of carbohydrate loading as part of an ERAS
programme, there is certainly a need to stimulate a call for a properly
conducted large-scale, randomised, controlled trial of its efficacy in
this group of patients. There is some evidence, albeit from small
studies, to suggest that carbohydrate loading pre-operatively can
be safe in patients with diabetes. Naturally there will be a need to
carefully monitor and support such patients – but this is integral
to the ERAS approach. Clearly, its potential to shorten hospital
stay, give a more rapid return to normal activities and reduce the
frequency of serious complications would be of particular benefit.
Conflict of interest None.
Funding None.
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