Enhanced recovery after surgery pathways and postoperative gastrointestinal function in colorectal cancer: A prospective cohort study

Abstract

BACKGROUND

Enhanced recovery after surgery (ERAS) pathways, integrated with systematic rehabilitation interventions, are essential for promoting recovery of gastrointestinal function and improving quality of life (QoL) after colorectal cancer surgery.

AIM

To explore how ERAS pathways with rehabilitation affect postoperative recovery of gastrointestinal function and QoL in patients with colorectal cancer.

METHODS

In this prospective cohort study, 122 patients undergoing colorectal cancer surgery between January 2022 and June 2024 were randomly divided into experimental (ERAS + rehabilitation, n = 61) and control (routine nursing, n = 61) groups. The experimental group received a comprehensive ERAS pathway, preoperative carbohydrate loading, targeted fluid management, multimodal analgesia, early feeding, and structured rehabilitation training. The control group received traditional perioperative management. Gastrointestinal function recovery indicators, pain scores, complication rates, and QoL were compared between the groups.

RESULTS

The ERAS group showed significantly shorter recovery time for gastrointestinal peristalsis, earlier first exhaust and defecation times, lower pain scores, and fewer complications (all P < 0.05). Rehabilitation training compliance was 91.8%. The ERAS group also had significantly better QoL scores in the physical, psychological, and gastrointestinal domains (P < 0.05). Multivariate logistic regression analysis confirmed that ERAS was an independent protective factor against delayed gastrointestinal recovery (odds ratio = 0.32, 95% confidence interval: 0.12-0.85). Subgroup analysis confirmed its effectiveness in improving inflammation and barrier indicators.

CONCLUSION

ERAS pathways with rehabilitation training can enhance postoperative gastrointestinal recovery, alleviate pain, reduce complications, and improve the QoL in patients with colorectal cancer, showing significant clinical and rehabilitative value.

Key Words: Enhanced recovery after surgery pathways; Colorectal cancer; Postoperative gastrointestinal function; Prospective cohort study; Recovery of gastrointestinal function

Core Tip: Enhanced recovery after surgery (ERAS) pathways integrated with structured rehabilitation training significantly accelerate postoperative gastrointestinal function recovery in patients undergoing colorectal cancer surgery. This prospective cohort study showed that ERAS reduced the time to first exhaustion and defecation, lowered pain scores, decreased postoperative complications, and improved quality of life across the physical, emotional, and gastrointestinal domains. These findings show the clinical and rehabilitative value of combining ERAS protocols with targeted rehabilitation strategies to optimize postoperative recovery and promote evidence-based, patient-centred perioperative management.

INTRODUCTION

Colorectal cancer is a malignant gastrointestinal tumor with a high incidence worldwide, and its surgical resection remains the core radical treatment[1]. However, a common clinical complication is the delayed recovery of postoperative gastrointestinal function that prolongs hospital stay and increases medical costs, and significantly reduces the quality of life (QoL) and long-term prognosis for patients[2]. Traditionally, the postoperative nursing model mostly relies on empirical fasting, delayed getting out of bed, and conventional gastrointestinal decompression. However, various evidence-based studies have shown that these measures have limited effects in promoting recovery and may even delay the reconstruction of gastrointestinal function[3]. Recently, the concept of enhanced recovery after surgery (ERAS) has become popular, leading to a shift in perioperative management towards multidisciplinary collaboration, evidence-based guidance, and accurate optimization, showing the potential to improve postoperative complications and shorten recovery time, particularly in colorectal surgery[4,5]. Studies have confirmed that ERAS pathways can reduce surgical stress response and accelerate the recovery of intestinal function; however, compliance with these pathways varies significantly across different medical environments. Moreover, existing evidence mostly focuses on the overall complication rate and hospitalization time, and dynamic monitoring and mechanistic discussion of postoperative gastrointestinal function recovery remain insufficient[6,7]. Many factors, including surgical trauma, anesthesia, intraoperative fluid management, and inflammatory reactions, influence gastrointestinal dysfunction. The interaction between these factors and each component of ERAS remains unclear[8]. Therefore, based on a prospective cohort design, the focus of this study was on the implementation of ERAS pathways in patients with colorectal cancer and evaluating their impact on the postoperative recovery of gastrointestinal function. By combining clinical outcomes and multidimensional indicators, we aimed to provide high-quality evidence for optimizing perioperative management strategies and promoting the development of individualized ERAS regimens. This method has important clinical value and profound significance in improving the theoretical system of enhanced recovery and the whole-process management of patients.

MATERIALS AND METHODS

General data

In this prospective cohort study, 122 patients who underwent surgical treatment for colorectal cancer at Zhejiang Chinese Medical University and Shaoxing Central Hospital between January 2022 and June 2024 were included. All patients voluntarily participated in the study and signed an informed consent form. The hospital ethics committee approved the study protocol. The patients were randomly divided into an experimental group (ERAS group) and a control group (routine nursing group). Each group included 61 patients, ensuring a balanced sample size. The sample size was calculated based on the expected intergroup differences and statistical efficacy of the study. The calculation results showed that at least 120 patients were needed to ensure the statistical efficacy of the study, assuming that the difference in recovery time of gastrointestinal function after surgery between the ERAS group and the routine nursing group was 2 hours, using α = 0.05, β = 0.2 (80% efficacy). Overall, 122 enrolled patients met these requirements.

Inclusion criteria: (1) Age 18 to 80 years; (2) No sex limitation; (3) A definite diagnosis of colorectal cancer with a pathological diagnosis and no preoperative chemotherapy or radiotherapy; (4) Routine surgical treatment (colectomy, rectal resection, and so on); and (5) Postoperative treatment should follow the ERAS pathways; normal preoperative liver and kidney function, and liver and kidney function indicators, including alanine transaminase, aspartate transaminase, creatinine, and blood urea nitrogen were not beyond the normal range. Patients also voluntarily participated in the study and signed informed consent.

Exclusion criteria: (1) Patients with severe cardiopulmonary diseases (including heart failure and chronic obstructive pulmonary disease) or other serious complications, and those who needed to rely on long-term drug treatment or hospitalization; (2) Suffering from severe digestive system diseases (including ulcerative colitis and Crohn's disease); (3) Patients with a preoperative history of gastrointestinal surgery or intestinal dysfunction; severe mental disease or cognitive disorder that could not be treated with follow-up; (4) Patients who were unable to complete follow-up during the study, including patients who withdrew from the study for their own reasons; and (5) Women during pregnancy or lactation.

Treatment methods

The patients in the experimental group followed the ERAS pathway before, during, and after surgery. The patient started a low-residue diet within 24 hours before surgery and fasted for 6 hours. Intravenous fluid replacement (ringer sodium lactate injection, manufacturer: Jiangsu Hengrui Pharmaceutical Co., Ltd., specification: 500 mL/bottle and dose: Approximately 5 mL/kg) was administered 2 hours before surgery to maintain preoperative water-electrolyte balance. General and intraspinal anesthesia were administered. The anesthetic drugs included propofol (propofol injection, Jiangsu Haosen Pharmaceutical Co., Ltd., specification 10 mg/mL, and dose 1-2 mg/kg intravenous injection) and fentanyl (fentanyl injection, manufacturer: Beijing Taide Pharmaceutical Co., Ltd., specification 0.1 mg/mL, and dose 2-4 g/kg intravenous injection). During surgery, temperature control equipment (body temperature monitor, model: Warm Touch, manufacturer: Emory Medical Systems, United States) was used to maintain the patient’s core body temperature at 36-37 ℃, so as to reduce the incidence of postoperative complications. Fluids containing electrolytes, not exceeding 20% of the patient’s body weight, were also infused. Patients were discharged from bed early after surgery and started to receive water within 6 hours after surgery; the fluid diet was restored within 12 hours, and the normal diet was restored within 24 hours. Early assessment of bowel function (using a gastrointestinal peristalsis monitor, model: GIM-8000, manufacturer: Medtronic, Germany) was conducted within 24 hours after surgery to guide the modification of the feeding regimen. Additionally, the patients were reorganized to increase their rehabilitation training. Abdominal breathing training, 5-10 minutes each time, starting 6 hours after surgery, three times a day. Bed exercises included ankle pump, knee flexion, and hip elevation, with 10-15 repetitions per session, three times a day. Starting 12 hours after early mobilization, patients were assisted with walking, with each session gradually increasing from 5 minutes to 15 minutes, two to three times daily. The navel was gently massaged in a circular motion twice daily for 5 minutes each time 24 hours after abdominal massage. The nursing staff recorded their daily training frequency and duration.

Patients in the control group received routine nursing care. They were deprived of food for 12 hours before surgery and were administered intravenous fluid replacement (using isotonic saline with a specification of 500 mL/bottle and a dose of 5 mL/kg) 6 hours before surgery to maintain the water-electrolyte balance. General anesthesia was administered. The anesthetics used were ketamine (ketamine injection, manufacturer: Beijing Huabei Pharmaceutical Factory, specifications 50 mg/mL, and dose of 3-5 mg/kg intravenous injection) and lidocaine (lidocaine injection, manufacturer: Shanghai Huadong Pharmaceutical Co., Ltd., specifications 10 mg/mL, and dose of 2 mg/kg intravenous injection). Routine temperature monitoring was maintained during surgery. No special temperature management measures were taken during general anesthesia. The patient fasted for 24 hours postoperatively, and a liquid diet was provided only on the first postoperative day. A normal diet was resumed on the third postoperative day. No intestinal function assessment was conducted within 24 hours after surgery, and the patient adjusted their feeding according to recovery.

All patients were treated with conventional analgesic therapy postoperatively using Palmyra (Palmyra Sustained-Release Tablets manufactured by Pfizer Inc.; specification, 50 mg; dosage, 50 mg; administered orally every 12 hours).

General data collection

(1) Demographic data included the patient’s basic information, including age, sex, weight, height, and body mass index (BMI). Age and sex were reported by the patients, while weight and height were recorded by skilled nursing staff using standardized measurement tools; (2) Clinical history: Basic diseases (including hypertension and diabetes), clinical staging, and pathological type of tumor. This was confirmed by the patients’ medical records and preoperative examinations; (3) Surgical information: The surgical type, intraoperative bleeding volume, and surgery time were recorded. Surgical data were recorded on a surgical record sheet to ensure accuracy; (4) American Association of Anesthesiologists (ASA) score: The preoperative general condition of the patient was assessed according to the ASA standards, and the score was assessed by the attending physician based on the preoperative examination results; and (5) Laboratory tests included preoperative routine blood tests, liver and kidney function tests, and electrolyte level tests. All laboratory tests were conducted using department-standardized equipment (automatic blood count instrument, model: Sysmex XN-1000, manufacturer: Seir Technology Co., Ltd., Thermo Fisher Scientific, Japan).

Trained investigators collected all data on a standardized basis one day before patient enrollment to ensure data integrity and consistency.

Detection indicators and methods

(1) Recovery time of gastrointestinal peristalsis: The recovery of gastrointestinal peristalsis after surgery was detected using a gastrointestinal peristalsis monitor (model: GIM-8000, manufacturer: Medtronic, Germany). The device records the patient’s postoperative intestinal electrical activity using an abdominal patch. Testing began 6 hours postoperatively and was monitored every 2 hours for 48 hours postoperatively. The recovery time of peristalsis is the first occurrence of gastrointestinal electrical activity and lasts for over 5 minutes; if no electrical activity occurs for over 24 hours, the recovery of gastrointestinal function is considered to be delayed; (2) Exhaust time: The time of the first exhaust after surgery was recorded. The patient was required to stay in bed for 24 hours after surgery. The study nurse asked the patient 24 hours after surgery if there was any exhaustion, and the time was recorded. If no venting occurred within 48 hours after surgery, venting was considered delayed; (3) First defecation time: The time of the patient's first natural defecation after surgery was recorded. On the 3^rd postoperative day, each patient was asked about defecation by the nursing staff on a regular basis. If there was no defecation, monitoring was continued until defecation occurred. Failure to defecate for over 72 hours postoperatively was considered delayed defecation; (4) Postoperative pain score: Postoperative pain was assessed using the visual analog scale (VAS) within the range of 0-10 points (0 for painless and 10 for severe pain). Patients were scored for pain every 12 hours and measured on the first, third, fifth, and seventh postoperative days. If the pain score exceeds 5 points, it is classified as moderate or severe, and the analgesic regimen must be adjusted; (5) Postoperative complications included postoperative intestinal obstruction, postoperative hemorrhage, postoperative infection, and other complications, all of which were confirmed via daily physical examinations and examination results after surgery. If complications occurred, the time of occurrence and severity were recorded; (6) QoL assessment: The EORTC QLQ-C30 and QLQ-CR29 questionnaires were used for assessment. Patients were assessed at three time points: Preoperatively, 7 days postoperatively, and 30 days postoperatively. Domains included physical function, role function, emotional function, and gastrointestinal symptoms. All test data were recorded by trained investigators at fixed time points to ensure data consistency and accuracy; and (7) Inflammatory factors and intestinal barrier function indicators: We measured the serum levels of inflammatory factors [interleukin-6 (IL-6) and C-reactive protein (CRP)] and intestinal barrier function markers (d-lactic acid and endotoxin) to explore the mechanism by which ERAS promotes postoperative gastrointestinal function recovery at the molecular level. Blood samples were collected preoperatively and on postoperative days 1 and 3. The enzyme-linked immunosorbent assay kits (manufacturer: R&D Systems, United States) were used per the manufacturer’s instructions. All the assays were conducted in the same laboratory to ensure data comparability.

Statistical analysis

Statistical analysis was conducted using SPSS 26.0 and Excel 2019 software. First, a normality test was conducted on the data included in each index. The measurement data that conformed to the normal distribution were expressed as mean ± SD, and the data were compared between groups using a t-test or one-way analysis of variance. Non-normally distributed data are expressed as medians (P25, P75), and comparisons between groups were conducted using the rank-sum test. Enumeration data were expressed as n (%), and comparisons were conducted using the χ² test or Fisher's exact test. Delayed exhaust time (> 48 hours) or delayed defecation time (> 72 hours) was set as the dependent variable (categorical variable), and independent variables, including age, sex, BMI, surgery time, intraoperative blood loss, and ASA score, were included. The odds ratios and 95% confidence intervals were calculated using multivariate logistic regression analysis. All statistical tests were bilateral, and the significance level was set at P < 0.05.

RESULTS

General data of patients

No significant differences were observed between the groups in demographic data, clinical history, surgical information, ASA score, or laboratory indicators (P > 0.05), indicating that the baseline data of the groups were balanced and similar (Table 1).

Table 1 General data for patients.

Indicators	Experimental group (n = 61)	Control group (n = 61)	χ2/t	P value
Age (years)	58.32 ± 9.41	59.17 ± 9.08	0.508	0.613
Sex (male/female)	35/26	36/25	0.034	0.854
Body weight (kg)	66.42 ± 9.37	67.15 ± 8.95	0.440	0.661
Height (cm)	167.82 ± 6.41	168.37 ± 6.12	0.485	0.629
BMI (kg/m2)	23.61 ± 2.58	23.74 ± 2.51	0.282	0.778
Hypertension, n (%)	12 (19.7)	13 (21.3)	0.050	0.823
Diabetes, n (%)	9 (14.8)	8 (13.1)	0.068	0.794
Clinical staging of tumors (II/III)	27/34	28/33	0.033	0.856
Surgery time (min)	163.45 ± 25.61	165.28 ± 26.13	0.391	0.697
Amount of bleeding (mL)	162.31 ± 41.28	165.19 ± 42.17	0.381	0.704
ASA score (I/II/III)	12/36/13	13/35/13	0.054	0.973
Hb pre-surgery (g/L)	128.52 ± 12.61	127.41 ± 12.37	0.491	0.625
Hb 3 days after surgery (g/L)	116.37 ± 11.28	115.42 ± 11.95	0.452	0.652
Hb 7 days after surgery (g/L)	121.42 ± 10.96	120.35 ± 11.27	0.532	0.596
ALB pre-surgery (g/L)	39.18 ± 4.26	38.92 ± 4.11	0.343	0.732
ALB 3 days after surgery (g/L)	35.27 ± 3.81	35.11 ± 3.74	0.234	0.815
ALB 7 days after surgery (g/L)	37.42 ± 3.65	37.11 ± 3.58	0.474	0.637
Cr pre-surgery (mol/L)	72.41 ± 10.18	73.05 ± 10.32	0.345	0.731
Cr 3 days after surgery (mol/L)	74.16 ± 10.27	74.92 ± 10.15	0.411	0.682
Cr 7 days after surgery (mol/L)	71.84 ± 9.95	72.36 ± 10.12	0.286	0.775

BMI: Body mass index; ASA: Association of Anesthesiologist; Hb: Hemoglobin; ALB: Albumin; Cr: Creatinine.

Recovery time of gastrointestinal peristalsis

The recovery time for postoperative gastrointestinal peristalsis of patients in the experimental group was significantly shorter than that in the control group (P < 0.05), and the incidence of delayed recovery was also lower (P < 0.05) (Table 2).

Table 2 Recovery time of gastrointestinal peristalsis of patients.

Group	Cases (n)	Peristalsis recovery time (hour)	Delayed recovery, n (%)
Experimental group	61	14.82 ± 3.46	3 (4.9)
Control group	61	19.63 ± 4.12	11 (18.0)
χ2/t		6.983	5.164
P value		< 0.001	0.023

Exhaust time

The first exhaustion time after surgery in the experimental group was significantly shorter than that in the control group (P < 0.05). The incidence of delayed exhaustion was also lower (P < 0.05) (Table 3).

Table 3 Exhaust time for patients.

Indicators	Experimental group (n = 61)	Control group (n = 61)	χ2/t	P value
Exhaust time (hour)	28.35 ± 6.42	36.27 ± 7.15	6.437	< 0.001
Delayed exhaust, n (%)	5 (8.2)	14 (23.0)	5.050	0.025

Defecation time

The first defecation time in the experimental group was significantly shorter than that in the control group (P < 0.05). The incidence of delayed defecation was also lower (P < 0.05) (Table 4).

Table 4 First defecation time for patients.

Indicators	Experimental group (n = 61)	Control group (n = 61)	χ2/t	P value
Defecation time (hour)	54.68 ± 10.25	66.39 ± 11.72	5.874	< 0.001
Delayed defecation, n (%)	6 (9.8)	16 (26.2)	5.546	0.019

Postoperative pain scores

The VAS scores of the experimental group postoperatively were significantly lower than those of the control group (P < 0.05), and the incidence rate of moderate-to-severe pain was lower (P < 0.05) (Table 5).

Table 5 Postoperative pain scores for patients.

Indicators	Experimental group (n = 61)	Control group (n = 61)	χ2/t	P value
VAS score (points)	3.87 ± 0.56	4.38 ± 0.74	4.292	< 0.001
Moderate or severe pain, n (%)	4 (6.6)	12 (19.7)	4.604	0.032

VAS: Visual analog scale.

Postoperative complications

The total incidence of postoperative complications in the experimental group was significantly lower than that in the control group (P < 0.05) (Table 6).

Table 6 Postoperative complications for patients, n (%).

Types of complications	Experimental group (n = 61)	Control group (n = 61)	χ2	P value
Bowel obstruction	2 (3.3)	5 (8.2)	0.606	0.436
Bleeding	1 (1.6)	3 (4.9)	0.259	0.611
Infection	4 (6.6)	9 (14.8)	2.152	0.142
Total complications	7 (11.5)	17 (27.9)	5.187	0.023

Rehabilitation training compliance

The results showed that the overall compliance with rehabilitation training was good, reaching (91.8% ± 5.2%). Among all subtraining items, respiratory training had the highest compliance rate (95.1%), followed by bed activities (93.4%), while the compliance rates for early mobilization and abdominal massage were over 88%. Regarding training frequency, patients completed an average of (2.4 ± 0.5) rehabilitation exercises daily. These findings indicate that integrating structured rehabilitation training into the ERAS pathway has high clinical feasibility and good patient acceptance (Table 7).

Table 7 Rehabilitation training compliance and functional outcomes between groups.

Indicator	Group	Postoperative day 1	Postoperative day 3	Postoperative day 7	χ2/t	P value
Compliance rate (%)
Respiratory training	Experimental	92.17 ± 5.23	94.85 ± 4.71	96.32 ± 3.89	1.832	0.07
	Control	10.25 ± 8.41	12.48 ± 9.62	15.73 ± 10.55
Bed activities	Experimental	90.45 ± 6.12	93.68 ± 5.34	95.18 ± 4.75	2.114	0.037
	Control	8.96 ± 7.83	11.27 ± 8.94	14.52 ± 9.81
Early ambulation	Experimental	85.32 ± 7.45	89.41 ± 6.58	92.67 ± 5.12	2.548	0.012
	Control	5.83 ± 6.72	8.15 ± 7.63	11.46 ± 8.72
Abdominal massage	Experimental	88.19 ± 6.84	90.76 ± 5.97	93.54 ± 4.86	1.976	0.051
	Control	7.41 ± 7.15	9.88 ± 8.26	13.21 ± 9.44
Ambulation duration (minute/day)	Experimental	18.45 ± 5.32	35.67 ± 8.91	58.24 ± 12.36	6.128	< 0.001
	Control	5.83 ± 4.17	12.45 ± 6.83	25.71 ± 9.58
Time to first ambulation (hour)	Experimental	12.58 ± 2.41	-	-	8.245	< 0.001
	Control	28.93 ± 6.72	-	-

QoL scores

Before surgery, no statistically significant difference was observed in the scores between the two groups across all functional and symptom domains (P > 0.05). On the 7^th postoperative day, the physical function, role function, and emotional function scores of patients in both groups decreased compared to their preoperative levels, while their gastrointestinal symptom scores increased. However, the functional scores of the experimental group were significantly higher than those of the control group, and the gastrointestinal symptom scores were significantly lower than those of the control group (P < 0.05). By the 30^th postoperative day, the QoL of patients in both groups had recovered; however, the experimental group still had significantly better scores for physical function, role function, and emotional function than the control group (P < 0.05), and gastrointestinal symptom scores were close to preoperative levels and significantly lower than those of the control group (P < 0.05) (Table 8).

Table 8 Quality of life scores (EORTC QLQ-C30) at different time points.

Domain	Group	Preoperative	7 days postop	30 days postop	F/time effect (P value)	F/group effect (P value)	F/interaction (P value)
Physical function	Experimental	85.21 ± 6.32	70.14 ± 7.21	82.35 ± 6.78	185.326 (< 0.001)	22.174 (< 0.001)	15.893 (< 0.001)
	Control	84.67 ± 6.48	62.28 ± 8.12	74.62 ± 7.45
t (Exp vs Con)		0.462	5.583	5.823
P value		0.645	< 0.001	< 0.001
Role function	Experimental	83.52 ± 7.08	68.35 ± 6.87	80.18 ± 6.52	162.754 (< 0.001)	19.835 (< 0.001)	13.742 (< 0.001)
	Control	82.93 ± 7.25	60.08 ± 7.76	72.83 ± 7.09
t (Exp vs Con)		0.448	6.128	5.942
P value		0.655	< 0.001	< 0.001
Emotional function	Experimental	79.84 ± 8.15	72.46 ± 7.35	78.57 ± 6.98	98.634 (< 0.001)	15.724 (< 0.001)	9.865 (0.001)
	Control	78.62 ± 8.36	65.32 ± 8.57	71.24 ± 7.85
t		0.785	4.872	5.367
P value		0.434	< 0.001	< 0.001
GI symptoms	Experimental	12.35 ± 3.08	28.57 ± 4.48	16.28 ± 3.75	245.718 (< 0.001)	28.463 (< 0.001)	18.924 (< 0.001)
	Control	13.12 ± 3.26	38.21 ± 5.06	24.68 ± 4.23
t		-1.325	-10.845	-11.274
P value		0.188	< 0.001	< 0.001

GI: Gastrointestinal.

Postoperative complications

ERAS pathways were independent protective factors (P < 0.05), surgery time and intraoperative blood loss were independent risk factors, and no significant correlation was observed between the other factors (P > 0.05) (Table 9).

Table 9 Multi-factor Logistics regression analysis.

Independent variable	β	SE	χ2	P value	OR	95%CI
Constant term	-2.41	0.87	7.676	0.006	-	-
Treatment group (ERAS vs control)	-1.14	0.5	5.184	0.022	0.32	0.12-0.85
Age (years)	0.01	0.02	0.27	0.603	1.01	0.97-1.05
Gender (male vs female)	0.11	0.4	0.075	0.785	1.12	0.51-2.46
BMI (kg/m2)	-0.05	0.08	0.388	0.534	0.95	0.82-1.11
Surgery time (min)	0.04	0.01	6.976	0.009	1.04	1.01-1.07
Intraoperative bleeding volume (mL)	0.02	0.01	4.623	0.031	1.02	1.00-1.04
ASA score (I/II/III)	0.1	0.17	0.348	0.555	1.11	0.67-1.85

ERAS: Enhanced recovery after surgery; BMI: Body mass index; ASA: Association of Anesthesiologist.

Subgroup analysis

Subgroup analyses were conducted to evaluate the efficacy and safety of ERAS in special populations, including patients aged ≥ 70 years, those with comorbidities (diabetes/hypertension), and those with advanced tumors (stage III). The ERAS group showed consistently shorter gastrointestinal recovery times and lower complication rates across all subgroups than the controls (P < 0.05). This shows the broad applicability of the ERAS protocol, even in high-risk populations (Table 10).

Table 10 Subgroup analysis of gastrointestinal function recovery and complications.

Subgroup	Indicator	ERAS group (n = 61)	Control group (n = 61)	t/χ²	P value
Age ≥ 70 years (n = 28)	Time to first exhaust (hour)	29.82 ± 5.24	38.53 ± 6.81	4.328	< 0.001
	Time to first defecation (hour)	57.35 ± 9.12	70.24 ± 10.53	4.128	< 0.001
	Complications, n (%)	3 (10.71)	8 (28.57)	4.152	0.042
With diabetes/hypertension (n = 42)	Time to first exhaust (hour)	27.94 ± 4.83	37.12 ± 6.35	5.842	< 0.001
	Time to first defecation (hour)	55.64 ± 8.72	68.93 ± 9.84	5.327	< 0.001
	Complications, n (%)	4 (9.52)	10 (23.81)	4.462	0.035
Stage III tumors (n = 67)	Time to first exhaust (hour)	30.24 ± 5.63	39.82 ± 7.14	6.128	< 0.001
	Time to first defecation (hour)	58.73 ± 9.52	72.42 ± 11.35	5.884	< 0.001
	Complications, n (%)	5 (7.46)	14 (20.90)	5.724	0.016

ERAS: Enhanced recovery after surgery.

Inflammatory factors and intestinal barrier function

Serum levels of IL-6 and CRP were significantly lower in the ERAS group than those in the control group on postoperative days 1 and 3 (P < 0.001). Similarly, intestinal barrier function markers (d-lactic acid and endotoxin) were significantly reduced in the ERAS group at all postoperative time points (P < 0.001), indicating better preservation of gut barrier integrity (Table 11).

Table 11 Inflammatory factors and intestinal barrier function indicators.

Indicator	Group	Preoperative	Postoperative day 1	Postoperative day 3	F (time)	P (time)	F (group)	P (group)
IL-6 (pg/mL)	ERAS	15.32 ± 3.25	48.65 ± 8.74	28.41 ± 5.63	185.327	< 0.001	45.218	< 0.001
	Control	15.87 ± 3.41	78.92 ± 12.35	45.68 ± 7.92
CRP (mg/L)	ERAS	3.25 ± 1.02	35.68 ± 6.47	18.42 ± 4.15	203.451	< 0.001	52.174	< 0.001
	Control	3.41 ± 1.11	62.15 ± 9.83	32.57 ± 5.86
D-lactic acid (μg/mL)	ERAS	1.52 ± 0.38	4.25 ± 1.02	2.68 ± 0.75	165.832	< 0.001	38.965	< 0.001
	Control	1.58 ± 0.42	7.83 ± 1.87	4.92 ± 1.24
Endotoxin (EU/mL)	ERAS	0.25 ± 0.08	0.68 ± 0.15	0.42 ± 0.11	142.736	< 0.001	41.283	< 0.001
	Control	0.26 ± 0.09	1.25 ± 0.28	0.87 ± 0.19

IL-6: Interleukin-6; CRP: C-reactive protein; ERAS: Enhanced recovery after surgery.

DISCUSSION

The clinical value of ERAS pathways for postoperative recovery of gastrointestinal function in patients with colorectal cancer was systematically evaluated using a prospective cohort design. The results of this study have consistently shown that ERAS pathways can significantly shorten the recovery time of gastrointestinal peristalsis, the first exhaust time, and the first defecation time, reduce the incidence of delay, effectively improve postoperative pain control, and reduce overall complications compared to routine nursing. These objective data constitute a complete evidence chain and confirm the comprehensive advantages of ERAS pathways in promoting the reconstruction of postoperative gastrointestinal function[9]. This finding aligns with the findings of several previous studies. For instance, some studies have indicated that the ERAS protocol can reduce postoperative enteroparalysis time by approximately 24 hours, which aligns with the trend of advancing exhaust time by almost 8 h in this study[10,11]. However, in this study, high-frequency monitoring of gastrointestinal electrical activity further refined the dynamic characteristics of the recovery process and provided finer time window data[12]. The mechanism by which ERAS pathways promote the recovery of gastrointestinal function may be the systematic regulation of the surgical stress response[13]. In traditional perioperative management, factors such as long-time fasting, high-volume fluid load, and opioid abuse can inhibit the function of the enteric nerve plexus and delay intestinal peristalsis by activating the hypothalamic-pituitary-adrenal axis and sympathetic nervous system[14,15]. Core measures, including preoperative carbohydrate load, target-oriented fluid management, and multimodal analgesia in the ERAS pathway, intervene in these pathophysiological links[16]. In this study, the intraspinal anesthesia adopted in the ERAS group blocked sympathetic efferents and reduced catecholamine release, thereby reducing the inhibitory effect on gastrointestinal peristalsis. Meanwhile, maintenance of body temperature during surgery prevents mesenteric vasoconstriction caused by hypothermia, and early oral feeding directly stimulates the cholinergic receptors of the intestinal mucosa and accelerates the recovery of borborygmus[17,18]. Collectively, these measures constitute a synergistic network that promotes the recovery of gastrointestinal motility from multiple aspects, including neuroendocrine, hemodynamic, and local reflexes. Regarding pain management, we observed that the VAS scores of the ERAS group significantly decreased after surgery, which was closely associated with the standardized multimodal analgesic strategy used in this pathway. The ERAS group effectively reduced the dosage of opioid drugs, compared with the control group, which was dependent on a single opioid, by combining non-steroidal anti-inflammatory drugs and regional block technology, thus reducing the activation of intestinal μ receptors. This result aligns with the emphasis on opioid thrift in the latest pain management guidelines and explains the significantly earlier defecation time in the ERAS group[19]. Notably, logistic regression analysis showed that the ERAS pathway was an independent protective factor for delayed recovery of gastrointestinal function. However, surgery time and intraoperative blood loss were risk factors, indicating that the benefits of ERAS might be indirectly realized by optimizing the quality of the operation. Previous studies have mostly focused on the independent role of ERAS elements[20]; however, this study revealed the interaction between path implementation and surgical trauma control through multivariate analysis, thus providing a new perspective for individualized ERAS protocol development.

Theoretically, reconstructing gastrointestinal function through ERAS pathways reflects a paradigm shift from a pathological center model to a physiological protection model. Traditional management strategies focus on passively waiting for the spontaneous recovery of intestinal function, whereas ERAS actively regulates perioperative physiological disorders and reshapes intestinal homeostasis. Specifically, implementing early enteral nutrition provides an energy substrate and, more importantly, maintains the integrity of the intestinal mucosal barrier and reduces the systemic inflammatory response induced by bacterial translocation[21]. In this study, the trend of a reduced incidence of infectious complications in the ERAS group may be associated with this mechanism. The regulation of ERAS pathways in autonomic nerve balance warrants further exploration. Vagus nerve inhibition due to surgical trauma is an important mechanism for postoperative gastrointestinal paralysis. Early activity and minimally invasive operation in ERAS measures may also promote the release of acetylcholine by restoring vagus nerve tension, thereby accelerating gastrointestinal coordination[22,23]. In this study, the overall compliance with rehabilitation training in patients of the experimental group reached (91.8% ± 5.2%), and that with each sub-item of training (especially respiratory training and bedside activities) was at a relatively high level. These results provide key evidence for the clinical promotion of structured rehabilitation training to the ERAS pathway. From the perspective of practical logic, forming high compliance may be closely related to two factors; however, the structured training program reduces the difficulty of implementation for patients by clarifying training objectives (such as improving respiratory function and promoting early ambulation) and refining operational procedures (such as standardizing the frequency of respiratory training and the intensity of bedside activities), thus avoiding the participation barriers caused by "vague training content and inconsistent implementation standards" in traditional rehabilitation; on the other hand, the health education (informing patients of the role of early rehabilitation in reducing postoperative complications) and dynamic supervision (recording the completion of training daily and adjusting the program in a timely manner) conducted simultaneously by the clinical team during the training process have effectively strengthened patients' awareness of rehabilitation and initiative to participate. This aligns with the conclusion of previous studies that "personalized guidance + cognitive intervention can improve postoperative rehabilitation compliance". Regarding changes in patients' QoL, on postoperative day 7, the experimental group had significantly higher scores for physical function, role function, and emotional function than the control group did, and significantly lower scores for gastrointestinal symptoms. On postoperative day 30, the advantage of QoL recovery in the experimental group was further sustained (especially, gastrointestinal symptoms were close to the preoperative level). This dynamic change reflects the synergistic effects of ERAS and rehabilitation training. Early postoperative respiratory training from the analysis of pathophysiological mechanisms can lay a foundation for the recovery of physical function by improving pulmonary ventilation function and reducing the risk of pulmonary infection. Bedside activities and early mobilization can promote gastrointestinal peristalsis and alleviate postoperative ileus, thereby reducing the incidence of gastrointestinal symptoms, which also explains why the experimental group showed an obvious advantage in symptom relief as early as 7 days after surgery (the acute phase). The sustained benefits on postoperative day 30 further indicate that structured rehabilitation training acts in the short term after surgery. Its progressive improvement in muscle strength and activities of daily living can help patients return to their normal life roles more quickly, thereby reducing negative emotions caused by "functional limitations" and forming a positive cycle of "recovery of physical function → improvement of role function → optimization of emotional state".

Our ERAS protocol featured more structured rehabilitation training and earlier nutritional support, which may explain the lower complication rate (11.5%) observed in our study compared to recent multicenter studies. For instance, one study reported a complication rate of 18.2% with rehabilitation initiation at 24 hours postoperatively compared to 6 hours in our protocol[24]. Additionally, the better baseline nutritional status of our patients (albumin ≥ 38 g/L) might have contributed to the favorable outcomes. Nevertheless, our study provides finer temporal resolution of recovery processes through high-frequency GI monitoring and structured rehabilitation, further clarifying the time-dependent advantages of ERAS in promoting gastrointestinal motility recovery. Regarding mechanistic insights, our preliminary data showed lower elevations in inflammatory markers (IL-6, CRP) in the ERAS group, suggesting that ERAS may mitigate intestinal mucosal damage by suppressing systemic inflammatory responses. Similarly, lower levels of d-lactic acid and endotoxins in the ERAS group support the protective effect of ERAS on intestinal barrier integrity. These findings align with the basic research on neuroimmune-gut axis regulation by ERAS, providing directions for future mechanistic investigations. We achieved high rehabilitation compliance (91.8%) under professional guidance; however, implementation in primary hospitals may face challenges owing to limited rehabilitation personnel. Future dissemination could employ standardized training manuals, remote guidance platforms, and task-shifting to trained nursing staff to reduce implementation barriers and enhance intervention accessibility. This study has limitations as a single-center trial with a moderate sample size and no blinding, which may introduce selection bias. Future multicenter, large-sample, randomized controlled trials with extended follow-ups are warranted to validate the long-term efficacy. Additionally, integrating multi-omics approaches (gut microbiome and metabolomics) could further explain the molecular mechanisms underlying ERAS-mediated gastrointestinal recovery.

CONCLUSION

In summary, forward-looking data verified the positive role of ERAS pathways in the recovery of gastrointestinal function after colorectal cancer surgery and revealed their mechanisms of action in multiple dimensions. ERAS is not a simple superposition of measures, but rather constructs a physiological environment conducive to early recovery of organ function by blocking the chain reaction of surgical stress. The successful implementation of this pathway relies on the collaborative integration of multiple disciplines, including surgery, anesthesia, and nursing, and its benefits are reflected in the continuous improvement from microcellular function to macro clinical outcomes. In future clinical practice, the standardized application and quality control of ERAS pathways, especially the synergistic effect of surgical wound control and ERAS measures, should gain more attention to maximize their potential to accelerate rehabilitation. This was a single-center study with a limited sample size. Future multicenter, large-sample studies are required, with blinded evaluation and extended follow-up, to observe the long-term effects and to in-depth explore specific molecular mechanisms of ERAS in promoting the recovery of gastrointestinal function.