We retrospectively reviewed the medical records of patients that underwent emergency GI surgery by a single surgeon from March 2008 to December 2011. The patients considered for inclusion in the present study had all undergone bowel resection and/or anastomosis. Patients that underwent simple appendectomy, cholecystectomy, primary repair of perforated viscera, or adhesiolysis without bowel anastomosis were excluded, as were patients with severe shock, sustained intestinal ischemia, uncontrolled bowel perforation, or short bowel syndrome. Additionally, to minimize severity differences in the study population, patients managed in the intensive care unit (ICU) for more than 3 days were also excluded.

Patients were allocated to an early group (E) or a late group (L) according to time of feeding commencement. Early feeding was defined as commencement of a liquid or soft diet via a tube or per os within 48 hours after surgery. The criteria to start enteral feeding included hemodynamic stability, secure bowel anastomosis performed, and no ischemic change of bowel observed in the operating room.

Feeding was started following the protocol described in Fig. 1. Tube feeding was selected when patient had a nasogastric, nasoenteric, or jejunostomy tube according to the patient's condition, such as mentality or underlying cerebral infarction, or a nasojejunal tube due to the gastric surgery. According to the recommendations of the Society of Parenteral and Enteral Nutrition, the purpose of early feeding is to promote early recovery and reduce time to discharge and postoperative complications. This study received Institutional Review Board approval.

Group clinical data and surgical outcomes were compared. The clinical data consisted of age, gender, Acute Physiology and Chronic Health Evaluation (APACHE) II score14 on ICU admission, causes of operation, operation type, operation sites, ratio of ICU care, vasopressor use and mechanical ventilation (MV), and the duration of MV. Surgical outcomes consisted of complication rates, complication types, and postoperative lengths of stay (LOS) in the hospital and in the ICU.

The criteria for ICU admission included advanced age (70≥age), presence of comorbidities, hemodynamic instability, and ventilator-dependent postoperative status, as well as patients that required intensive monitoring and may have potentially needed immediate intervention. Severe shock was defined as a mean arterial pressure maintained at >60 mm Hg (or >80 mm Hg if the patient had baseline hypertension) with the support of a vasopressor, such as high dose dopamine (>15 mcg/kg/min) or norepinephrine (>0.25 mcg/kg/min), after adequate fluid resuscitation.15 Short bowel syndrome was defined as <1.5 meters of small intestine remaining after surgery.16 Pulmonary complications include pneumonia, atelectasis, and pleural effusion. Diarrhea was defined as >3 times per day and/or a stool volume in excess of 500 mL/day. Ileus was defined as partial or complete non-mechanical blockage of the intestine as confirmed by simple abdominal radiography.

All values are presented as percentages or medians and ranges. Categorical variables were analyzed using the chi-square test, and continuous variables were analyzed using Student's t-test. Statistical analysis was performed using SPSS software version 18.0 (SPSS Inc., Chicago, IL, USA). Statistical significance was accepted for p values of <0.05.

One hundred and twelve patients were initially considered for this study. However, 9 patients were excluded based on a contraindication to enteral feeding (four cases of severe shock, three cases of short bowel syndrome, one intestinal ischemia, and one sustained bowel perforation), and another 19 were excluded due to ICU stay of more than 3 days after surgery. Finally, 84 patients were included the study cohort. There were 47 men and 37 women, and their median age was 64 years (range, 16-102). Median APACHE II score on ICU admission was 16 (range, 10-34). Fifty-three patients (63.1%) were managed in the ICU, and seven (8.3%) required a vasopressor due to immediate postoperative hypotension. Accompanying MV was performed in 22 patients (26.2%), and the median duration thereof was 1 day (range, 1-3). Median postoperative LOSs in the hospital and in the ICU were 11 (range, 4-72) and 2 days (range, 1-3), respectively. The most common cause of surgery was bowel perforation (n=37, 44.0%), followed by intestinal obstruction (n=22, 26.2%). The small bowel was the most common operation site (n=43, 51.2%), followed by the colon (n=32, 38.1%). The most common type of surgery was segmental resection with primary anastomosis of the small bowel (n=33, 39.3%). Oral feeding was performed in 65 patients (77.4%), while tube feeding was performed in 19 patients (22.6%). Fifty-two patients (61.9%) experienced a postoperative complication, among which wound problems (infection or seroma) were the most common. Twenty-five patients (29.8%) experienced a pulmonary complication, consisting of atelectasis in eight, pneumonia in two, and pleural effusion in 15.

Group E comprised 44 patients (52.4%) and group L contained 40 patients (47.6%). In group E, 18 patients (40.9%) started feeding within 24 hours. Five patients (11.4%) were forced to stop feeding in group E (four cases of ileus, one anastomosis leakage), while 5 patients (12.5%) were forced to stop feeding in group L (four cases of ileus, two diarrhea).

No significant intergroup differences were found with respect to cause (Table 1), site (Table 2), type of operation (Table 3), gender, age, APACHE II score on ICU admission, gastric residual volume before feeding, ratio of vasopressor use, ICU care, and MV or duration of MV (Table 4). However, postoperative LOSs in the ICU and hospital were significantly longer in group L. The incidences of postoperative complications were not significantly different between the two groups (Table 5). However, pulmonary complications such as atelectasis, pneumonia and pleural effusion were significantly more common in group L. Five patients in group L were managed by percutaneous catheter drainage due to pleural effusion. However, no patient in group E was managed in this manner due to pleural effusion.

An intra-abdominal abscess developed in 2 patients (1 in each group), but both cases were well controlled by percutaneous catheter drainage. One patient in group E, who received pyloric exclusion and gastrojejunostomy due to duodenal perforation, required re-operation to treat anastomotic disruption, but recovered well after re-operation. No postoperative mortalities were recorded in the present study.