This study evaluated the impact of a preoperative carbohydrate oral drink on the postoperative Neutrophil / Lymphocyte Ratio (NLR) and the incidence of postoperative complications after elective open colon surgery compared to the conventional preoperative fasting protocol. Hypothesis was: preoperative carbohydrate loading reduces postoperative NLR value and reduces the incidence and severity of postoperative complications in colorectal surgery.
This prospective randomized, controlled clinical study was carried out in the Department of Anesthesiology and Intensive Care Unit and Department of Surgery at the Cantonal Hospital Zenica, Bosnia and Herzegovina. The study protocol was approved by the local Ethics Committee. A total of 60 participants who scheduled for elective open colon surgery and fulfilled study criteria were included into study. The purpose and procedures of the study were fully explained and voluntary, informed, written consent was obtained from each participant. The participants were randomly allocated into two equal groups, depending on the preoperative treatment. There were no reliable published data for effects of preoperative carbohydrate loading on postoperative NLR values. Based on our hypothesis, a pilot study was performed with ten patients per group. Mean postoperative NLR value was 8,67±4,98 in the participants with a conventional preoperative fasting protocol versus 4,76±2,83 in the participants with preoperative carbohydrate loading. Sample size was estimated using sample size calculator software and power analysis with 95% confidence interval and power of 80%. Statistical significance was considered as p\< 0,05. The calculation indicated 27 participants per group would be sufficient to detect a difference of 3,91 with a standard deviation of 4,93 in NLR value between the groups. Assuming dropout of 10%, 30 participants per group were included. Block randomization was used with a block size of six and a 1:1 group ratio. A computer-generated random numbers indicating preoperative intervention, were sealed in opaque envelopes. An investigator who conducted randomization and opened the envelopes the night before surgery was blinded to the study protocol as well as the surgeons, nurses, anesthesiologists and staff involved in data collection. The participants in the Fasting group (control group) stopped oral intake at 12:00 pm the night before surgery and underwent to a conventional preoperative fasting protocol. Participants in the Carbohydrate group (experimental group) consumed 400 ml of a clear carbohydrate solution at 10:00 pm the night before surgery and 200 ml of a clear carbohydrate solution, 2 hours prior induction of anesthesia. All participants underwent general anesthesia followed by colorectal surgery. Fasting peripheral venous blood samples were collected at 06:00 am on the day of surgery (basal value), at 06:00 am on the first postoperative day, at 06:00 am on the third postoperative day and at 06:00 am on the fifth postoperative day. White blood counts were analysed with automated differential counts. The NLR value was obtained by dividing the absolute neutrophil count and the absolute lymphocyte count. All participants were followed up to 30 days post-surgery to assess postoperative complications and readmission rate. After discharge, participants were called by phone, once a week. Postoperative complications were graded for incidence and severity using the Clavien-Dindo Classification of Surgical Complications. Demographic and surgical data of the participants were recorded: age, sex, body weight, body mass index, American Society of Anesthesiologists (ASA) physical status class, nutritional status of the participants according to Nutritional Risk Screening 2002 (NRS-2002), tumor localization and duration of surgery.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
60
The participants of experimental group consumed 400 ml of a clear carbohydrate drink (12,5 gr/100 ml carbohydrate, 50 kcal/100 ml, pH 5.0) at 10:00 pm the evening before surgery and 200 ml of the carbohydrate drink on the day of surgery, 2 hours before induction of anesthesia. After surgery the participants fasted until the recovery of function of the bowel.
Cantonal Hospital Zenica
Zenica, Bosnia and Herzegovina
The mean change in NLR values between conventional preoperative fasting protocol and a preoperative carbohydrate loading
White blood counts with automated differential counts were analysed from peripheral venous blood samples using fluorescence flow cytometry method. The NLR value was calculated by following equation: NLR = the absolute neutrophil count (range of normality 4,0-7,0x10ᶺ9/L) / the absolute lymphocyte count (range of normality 1-3,7x10ᶺ9/L).
Time frame: fasting peripheral venous blood samples were collected at 06:00 am on the day of surgery (basal value), at 06:00 am on the first postoperative day, at 06:00 am on the third postoperative day and at 06:00 am on the fifth postoperative day.
The mean change in delta NLR value between conventional preoperative fasting protocol and a preoperative carbohydrate loading
Delta NLR value was defined as dynamic change in NLR value from basal value to the highest measured post-surgery NLR value. Delta NLR was calculated using following equation: Delta NRL = the highest measured post-surgery NLR value - basal NLR value.
Time frame: fasting peripheral venous blood samples were collected at 06:00 am on the day of surgery (basal value), at 06:00 am on the first postoperative day, at 06:00 am on the third postoperative day and at 06:00 am on the fifth postoperative day.
The mean change in incidence and severity of postoperative complications assessed using the Clavien-Dindo Classification of Surgical Complications between conventional preoperative fasting protocol and a preoperative carbohydrate loading
Postoperative complications were graded as follow: Grade I considered any deviation from the normal course without the need for pharmacological treatment or surgical, endoscopic and radiologic interventions. Grade II required pharmacological treatment with drugs other than such allowed for Grade I complications. Grade I and Grade II were considered minor postoperative complications. Grade III required surgical, endoscopic or radiological intervention without or with general anesthesia. Grade IV considered life-threatening complication required intensive care unit management. Grade V included death of patient. Grade III, IV and V were considered major complications.
Time frame: the incidence and severity of postoperative complications were assessed up to 30 days post-surgery. After discharge, participants were called by phone once a week and finally on the 30th day post-surgery.
The mean change in characteristics of postoperative complications between conventional preoperative fasting protocol and a preoperative carbohydrate loading
Characteristics of postoperative complications included: overall number of complications per group, number of participants without complications per group, number of participants with complications per group, number of participants with 1 complication per group, number of participants with 2 complications per group, number of participants with \>2 complications per group and readmission rate per group within 30 days post-surgery.
Time frame: the characteristics of postoperative complications and readmission rate were assessed up to 30 days post-surgery. After discharge, participants were called by phone once a week and finally on the 30th day post-surgery.
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