Effects of preoperative fasting abbreviation with carbohydrate and protein solution on postoperative symptoms of gynecological surgeries: double-blind randomized controlled clinical trial.

Objective: to investigate the effects of preoperative fasting abbreviation, a recommendation of Postoperative Accelerated Total Recovery protocol (ACERTO protocol), on postoperative symptoms of patients undergoing gynecological surgeries. Methods: a double-blind randomized controlled study of 80 gynecological surgeries performed from January to June 2016. The patients were randomly allocated into two groups: Controle Group, with 42 patients, and Juice Group, with 38 patients, who received 200ml inert solution or 200ml carbohydrate- and protein-enriched liquid, respectively, four hours before surgery. The postoperative symptoms studied were thirst, hunger, pain, agitation, satisfaction, and well-being in both groups. To measure the intensity of symptoms, we used the Visual Analog Scale (VAS), associated with the Facial Scale (FS) for pain, applied ten hours after surgery. Results: patients in the Juice Group had less pain (3.51x1.59), thirst (3.63x0.85), hunger (3.86x2.09), and agitation (2.54x0,82) in relation to the Controle Group (P<0.05). Satisfaction (6.89x8.68) and well-being (5.51x7.12) variables were higher (P<0.05) when the carbohydrate- and protein-containing liquid (Juice Group) was ingested in relation to the inert solution (Controle Group). Conclusion: the abbreviation of preoperative fasting with carbohydrate- and protein-containing liquid before gynecological surgeries reduces thirst, hunger, pain, agitation, and favors greater satisfaction and well-being than inert solution ingestion.

In addition, current evidence-based guidelines from anesthesiology societies in the United States, Canada, and Europe support the abbreviation of preoperative fasting with clear carbohydrateenriched liquids with or without protein 7,8 . A contraindication to shortening preoperative fasting is gastroesophageal reflux, since gastroparesis associated with gastroesophageal reflux may delay gastric emptying and predispose to bronchial aspiration 9 .
The abbreviation of preoperative fasting, as recommended by ERAS and ACERTO perioperative care protocols, is often related to abdominal [10][11][12][13][14] , oncologic 15 , and pediatric 16 surgeries. Positive effects are described in terms of satisfaction, recovery improvement, and even muscle strength recovery, suggesting lower muscle proteolysis due to surgical metabolic stress 17 . One of the co-authors generated the random allocation sequence, enrolled the participants, and knew about the allocation, not participating in the liquid delivery. Another co-author attributed the intervention to the participants. This co-author did not know which liquid would be offered to the patient. The patient also did not know which liquid to take, characteristic of the double-blind study. Shielding was performed for the patients and authors responsible for the intervention and data collection, with allocation data stored in a sealed envelope, only opened after data collection for result analysis. The two groups were: Control Group and Juice Group, which received, respectively, four hours before surgery, 200ml inert solution (composed of distilled water, four drops of red dye, and two drops of sucrose sweetener) and 200ml clarified supplement, rich in carbohydrate (89%), and whey protein (11%) produced by a pharmaceutical industry, offered to patients without packaging label.
The following clinical parameters were analyzed: age, weight, height, and body mass index (BMI). The parameters selected for analysis of postoperative symptoms were: thirst, hunger, pain, agitation, satisfaction, and well-being. The instrument used to measure the quality of recovery after surgery was the Visual Analog Scale (VAS), for all parameters, associated with the Facial Scale (FS) for pain. VAS questionnaire was administered ten hours after surgery.
Sample size (at least 30 patients in each group) was determined for identification with 95% confidence level (error a=0.05), a difference if there were at least 5 VAS points between the mean parameters of the two evaluated groups. Descriptive analysis was performed, presenting measures of central tendency and dispersion for continuous variables and frequencies in percentages for qualitative variables. Chi-square test or Fisher's exact test was used to verify the association between groups and qualitative variables. The significance level was of 0.05. Statistical analyses were performed using SPSS 20.0 software (Statistical Package for the Social Sciences).

RESULTS
Of the 124 patients scheduled for gynecological surgery from January to June 2016, 23 did not agree to participate in this study and 22 were excluded. The study began with 79 women and 80 cases (one patient underwent two procedures during the study four months apart and agreed to participate twice). Therefore, the sample consisted of 80 cases, 42 in the Control Group and 38 in the Juice Group. Of these patients, 74 completed the protocol, 40 from the Control Group and 34 from the Juice Group (Figure 1). Data in table 1 show a paired sample between groups, with no statistical difference in clinical parameters. There were no anesthetic complications.

DISCUSSION
Although the vast majority of studies derived from ERAS protocol employ carbohydratecontaining liquid, the relevance of this study is that it follows one of the classic recommendations of ACERTO protocol which supports the addition of protein to carbohydrate in the preoperative fasting abbreviation liquid. The mentioned formulation is emphasized in other recent studies to provide the benefits of nocturnal non-starvation before surgery 8 . According to Perrone et al. 22 , these new formulas may improve postoperative muscle strength and reduce fatigue, anxiety, and discomfort, as well as decrease the metabolic response to trauma. They report that whey protein contains a high level of essential amino acids (leucine, isoleucine, and valine) which are rapidly used by skeletal muscle during stress and stimulate protein synthesis.
In addition, whey protein has a high degree of digestibility and rapid absorption in the small bowel.    The practice did not offer additional risks and provided greater comfort and humanization in the perioperative care of gynecological surgeries.
It can therefore be encouraged with the aim of accelerating postoperative recovery and adding satisfaction in the quality of hospital care in gynecological surgeries.