This was a randomized, double-blind, clinical study carried out at the Julio Muller
University Hospital (Mato Grosso State, Brazil). The study was approved by the hospital
Research Ethics Committee registered under number 723/CEP-HUJM/09 and is in accordance with
the ethics principals set out in the Helsinki Declaration (2000), and meets Brazilian
national legal specifications.
Inclusion criteria includes adults (18-65 years-old), of both sexes, and candidates to
elective major operations such as subtotal gastrectomy, colectomy, and anterior resection of
the rectum for malignancies. Exclusion criteria were having diabetes mellitus, chronic kidney
failure, chronic liver disease or serum bilirubin greater than 2 mg/dL, body mass index (BMI)
above 35Kg/m2, American Anesthesiologists Association (ASA) score above 3, gastro-esophageal
reflux, gastroparesis or intestinal obstruction. Patients with any non-compliance with the
study protocol, or who had associated operations, or presented severe intraoperative
complications (any type of shock, cardiac arrest, coagulations problems), or experienced
prolonged operations (lasting more than 6 hours) were also excluded.
Patient randomization was carried out on admission to the hospital using random numbers
issued by a computer program (www.graphpad.com). For the randomization the precepts of the
CONSORT flow diagram were followed.
The patients were randomized into two groups: the study group and the control group. The
patients were given a specific drink to their group on the evening prior to surgery and three
hours before the operation. The study group received 400 ml (evening drink) or 200 ml (3h
prior to operation drink) of a solution containing 11% de protein (pea hydrolized proptein),
89% de carbohydrates (maltodextrin 79% and saccharose 21%) e 0% of lipids (Providextra,
Fresenius Kabi, São Paulo, Brasil) and the control group received conventional 6-8h fast. All
the patients fasted for solids at least 6 hours from the operation.
On the day before the surgery and on the second postoperative day blood samples were
collected for glucose, insulin, triglycerides, albumin, pre-albumin, CRP, and α-1-acid
glycoprotein (α-1-GA) assays. The HOMA-IR (Homeostasis Model Assessment-Insulin Resistance)
equation was used to assess insulin resistance according to the formula: HOMA-IR = insulin
(µU/mL) x glycaemia (mg/dL) / 405. To assess inflammatory activity the PINI (CRP (mg/L) x
α-1-GA (mg/L)/ albumin (g/L) x pre-albumin (mg/L) and the CRP/albumin ratio were used.
The mean outcome variable was the length of postoperative stay. Other endpoints included the
infectious morbidity, the insulin resistance assessed by HOMA-IR, and the inflammatory
indexes or markers mentioned above.