Each of the steps outlined in the present ERAS is based on scientific evidence. For example, patient education is reported to be important in the response to surgery. Now-classic studies  have shown that informed patients require less analgesia in the postoperative period and indeed experience significantly less pain than uninformed patients. More recent work has shown that adequate preoperative information reduces patient anxiety before surgery and may also hasten postsurgical recovery [3, 13, 14].
A number of studies on programmed colon surgery have brought into doubt the need for preoperative mechanical cleansing of the intestine [3, 15]. The need for strict preoperative fasting has also been recently questioned. Most clinical practice guides suggest a period of absolute fasting of between two and six hours, but recent studies indicate that taking a carbohydrate-rich drink before surgery may reduce the endocrine catabolic response and improve insulin resistance [3, 16], improving surgical results and hastening recovery. The present ERAS included the administration of carbohydrate-rich drinks (4 × 200 ml) one day prior to surgery plus two further such drinks (2 × 200 ml) on the morning of surgery. The protocol also included the administration of goal directed fluids made possible by the standard use of oesophageal Doppler monitoring [3, 17–21], temperature control to avoid hypothermia , and the non-routine use of a nasogastric tube; meta-analyses of several trials suggest the latter may reduce pulmonary complications [3, 22]. A further measure was the avoidance of routinely using drainage; several randomised trials have suggested that drainage is of no benefit [3, 23, 24]. Drainage can be avoided in most patients or limited to a short period, facilitating early mobilisation , a measure also called for by the ERAS followed. Finally, although taking food orally is commonly limited in the postoperative period, a number of studies have shown that it is safe even after colon surgery involving anastomosis [3, 25, 26]; it was therefore included in the present ERAS.
Additional variables not explicitly included in the ERAS were also measured: use of prophylactic medication for postoperative vomiting and nausea, use of epidural anaesthesia , and opioid-free pain control, it has been reported that opioid-free or opioid-reduced analgesia may hasten recovery .
When protocols such as the present are implanted, the goal is that there should be full compliance with all measures outlined. However, full compliance is commonly very difficult to achieve . In the present work the overall compliance rate was 65%, but varied widely in its different components. Patients received information in nearly all cases, while compliance with the provision of early postoperative fluids seemed particularly difficult.
The items of the protocol with less compliance were early oral fluid administration, goal-directed fluid therapy and early mobilization. The reason why these items obtained different compliance with the protocol could be the taste of oral fluid, rejection by patients, unavailability of devices and temporary employment of some healthcare providers involved in the ERAS. Probably the implementation could improve involving and training all the professionals who assist the patients included in the protocol and identifying these patients with signboards on bedside.
Missing values were most important for the variable surgical approach with 6.2% of them, being lower in the other variables.
The rates of complications and mortality recorded were similar to those reported by other authors in randomized controlled trials [5, 8–11]. In the present work the most common complication was wound infection. These programmes do not, therefore, appear to place the patient at any extra risk. Our results are similar to previous multicenter studies [27, 28] in terms of surgical complications, mortality and readmission rate. The surgical complication rate was 24% compared to the 14.1% reported by Schwenk et al  and 20% reported by Braumann et al . The mortality rate was 1% compared to the 0.8% reported by Schwenk et al  and 0,4% reported by Braumann et al . The readmission rate was 2.7% compared to the 3.9% reported by Schwenk et al  and 4% reported by Braumann et al .
Finally, the use of the present ERAS was associated with a preoperative hospital stay of fewer than 24 h and an overall mean stay of 6 days. In other recently published Spanish multicenter study, including data from 50 hospitals, the mean postoperative stay after colorectal resection was 12.36 days .