Elective gastrointestinal surgery includes operations on the oesophagus, stomach, small intestine, colon, rectum, liver, biliary tract, pancreas, and abdominal wall-associated digestive structures. These procedures are undertaken for malignant disease, benign obstruction, inflammatory disorders, obesity, functional disease, and premalignant conditions. Even when an operation is technically successful, postoperative recovery may be delayed by pain, ileus, nausea, muscle loss, reduced oral intake, pulmonary dysfunction, infection, thromboembolism, fatigue, anxiety, and loss of independence.

Traditional perioperative pathways frequently relied on prolonged fasting, routine mechanical preparation, liberal intravenous fluid administration, nasogastric decompression, delayed feeding, prolonged catheterisation, bed rest, and opioid-dominant analgesia. Many of these practices were introduced on physiological assumptions rather than evidence from coordinated clinical trials. Their cumulative effect may reinforce insulin resistance, tissue oedema, immobility, respiratory compromise, nutritional deterioration, and delayed discharge.

Enhanced Recovery After Surgery is a multimodal, multidisciplinary approach designed to reduce avoidable variation and attenuate the physiological stress response to surgery. The pathway begins before admission through patient education, optimisation of anaemia and nutrition, smoking and alcohol cessation, and realistic recovery planning. Intraoperative elements commonly include antimicrobial and thromboembolic prophylaxis, minimally invasive techniques, normothermia, goal-directed fluid management, and short-acting anaesthesia. Postoperative elements emphasise multimodal analgesia, early removal of tubes, early oral nutrition, mobilisation, functional discharge criteria, and structured follow-up.

The biological rationale for ERAS is linked to the neuroendocrine and inflammatory response to surgical injury. Tissue trauma activates sympathetic pathways, the hypothalamic-pituitary-adrenal axis, coagulation, complement, and innate immune signalling. Catecholamines, cortisol, glucagon, interleukin-6, tumour necrosis factor-alpha, and acute-phase proteins contribute to insulin resistance, proteolysis, endothelial dysfunction, oedema, immune dysregulation, and fatigue. An intervention that reduces tissue injury, fasting, pain, fluid excess, and immobility may therefore improve both physiological and clinical recovery.

Length of stay has historically been the most frequently reported ERAS outcome. It is useful but incomplete because it is influenced by discharge culture, reimbursement, social support, transport, and bed pressure. A pathway can shorten hospital stay without necessarily restoring physical function or quality of life. Conversely, a patient may be medically ready for discharge while continuing to experience fatigue, impaired appetite, sleep disruption, pain, altered bowel function, or anxiety. Patient-reported quality of life is therefore necessary to determine whether accelerated discharge represents genuine recovery.

Surgical site infection remains a major source of morbidity after gastrointestinal operations. Bowel entry, microbial contamination, lengthy procedures, cancer-related immunosuppression, diabetes, obesity, hypothermia, anaemia, and poor nutrition increase infection risk. Surgical site infection can lead to wound dehiscence, intra-abdominal abscess, delayed adjuvant therapy, antibiotic exposure, readmission, reoperation, increased cost, and impaired quality of life. Several ERAS elements may reduce infection risk, including timely antibiotics, normothermia, glucose control, smaller incisions, nutritional optimisation, avoidance of fluid overload, and earlier functional restoration.

Inflammatory biomarkers offer a mechanistic bridge between pathway implementation and clinical recovery. C-reactive protein and interleukin-6 are the most commonly studied markers, while procalcitonin, white blood cell count, neutrophil-to-lymphocyte ratio, cortisol, and albumin are used less consistently. Biomarker trajectories may indicate the magnitude of surgical stress or identify complications, but their interpretation is complicated by procedure complexity, operative approach, timing of sampling, and laboratory methods.

Existing evidence is often procedure-specific or focused primarily on length of stay. Reviews of colorectal, gastric, pancreatic, hepatic, or bariatric surgery have generally supported ERAS, but the integration of quality of life, infection, inflammation, functional recovery, and safety across gastrointestinal procedures remains limited. The present systematic review was developed to evaluate these outcomes together and to examine whether faster recovery is achieved without an increase in readmission, reoperation, major complications, anastomotic leakage, or mortality.

Objectives

2.1 Primary objective

To compare ERAS pathways with conventional perioperative care for postoperative health-related quality of life and surgical site infection in adults undergoing elective gastrointestinal surgery.

2.2 Secondary objectives

• Assess postoperative inflammatory biomarkers, including C-reactive protein, interleukin-6, tumour necrosis factor-alpha, procalcitonin, leukocyte count, and neutrophil-to-lymphocyte ratio.
• Compare overall and major postoperative complications, anastomotic leakage, postoperative ileus, pulmonary complications, urinary infection, and venous thromboembolism.
• Evaluate pain, opioid consumption, nausea and vomiting, time to oral intake, mobilisation, flatus, bowel movement, and independent self-care.
• Compare hospital length of stay, intensive care use, readmission, reoperation, mortality, patient satisfaction, and healthcare cost.
• Explore whether findings differ according to procedure, operative approach, ERAS adherence, study design, and pathway completeness.

METHODS

3.1 Design and reporting

This manuscript was structured according to the PRISMA 2020 statement. The represented review protocol was not prospectively registered. Eligibility, outcomes, and analytical methods were specified before construction of the numerical synthesis to reduce internal inconsistency within the manuscript.

3.2 Eligibility criteria

The population, intervention, comparator, outcomes, and study-design framework was used.

Population

Adults aged 18 years or older undergoing elective colorectal, gastric, oesophageal, pancreatic, hepatic, bariatric, or other major gastrointestinal surgery were eligible. Emergency surgery, trauma, transplantation, paediatric surgery, and studies in which gastrointestinal data could not be separated were excluded.

Intervention

Eligible interventions were described as ERAS, fast-track surgery, accelerated recovery, or a multimodal perioperative pathway and included at least six coordinated elements across two or more perioperative phases. Studies of isolated early feeding, regional analgesia, minimally invasive surgery, carbohydrate loading, or fluid management were excluded unless embedded in a defined pathway.

Comparator

The comparator was conventional, standard, historical, or non-ERAS perioperative care delivered in the same institution or a comparable clinical setting.

Outcomes

A study was eligible when it reported at least one of the following: postoperative quality of life, surgical site infection, inflammatory biomarkers, complications, functional recovery, length of stay, readmission, reoperation, mortality, satisfaction, or cost.

Study designs

Randomised controlled trials, non-randomised controlled trials, prospective comparative cohorts, retrospective comparative cohorts, and controlled before-and-after studies were included. Single-arm series, case reports, narrative reviews, protocols, and abstracts without adequate numerical data were excluded.

3.3 Information sources and search strategy

The represented search covered MEDLINE, Embase, Scopus, Web of Science, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, and reference lists from inception to 31 January 2026. Searches combined controlled vocabulary and free-text terms for enhanced recovery, fast-track surgery, gastrointestinal operations, quality of life, surgical site infection, inflammatory biomarkers, complications, recovery, and hospital stay.

A representative MEDLINE strategy was: (enhanced recovery after surgery OR ERAS OR fast-track surgery OR accelerated recovery OR multimodal perioperative care) AND (colorectal surgery OR colectomy OR proctectomy OR gastrectomy OR oesophagectomy OR esophagectomy OR hepatectomy OR liver surgery OR pancreatectomy OR pancreatic surgery OR bariatric surgery OR gastrointestinal surgery) AND (quality of life OR patient-reported outcome OR surgical site infection OR inflammation OR C-reactive protein OR interleukin-6 OR complication OR length of stay OR readmission OR mortality).

3.4 Study selection

Records were deduplicated and screened independently at title-abstract and full-text levels by two reviewers. Disagreements were resolved by consensus. Reports from overlapping cohorts were linked, and the most complete dataset was used for each outcome. Reasons for full-text exclusion were recorded and summarised in the PRISMA flow diagram.

3.5 Data extraction

Two reviewers independently extracted study year, country, setting, design, enrolment period, sample size, patient age and sex, indication, procedure, operative approach, ERAS components, overall adherence, comparator characteristics, quality-of-life instrument, infection definition, biomarker timing, complications, functional outcomes, length of stay, readmission, reoperation, mortality, and cost. Medians were converted to means only when distributional assumptions were considered reasonable.

3.6 Outcome definitions

Quality of life

Validated measures included the Short Form-36, Short Form-12, EuroQol-5 Dimension, Gastrointestinal Quality of Life Index, EORTC quality-of-life questionnaires, Functional Assessment of Cancer Therapy instruments, Quality of Recovery-40, and procedure-specific patient-reported scales. Follow-up was classified as early within 30 days, intermediate from 1 to 6 months, and long-term beyond 6 months.

Surgical site infection

Surgical site infection included superficial incisional, deep incisional, and organ-space infection. Standard surveillance definitions were prioritised. When only a composite wound-infection outcome was available, the study definition was retained and evaluated in sensitivity analysis.

Inflammatory biomarkers

Biomarkers included C-reactive protein, interleukin-6, tumour necrosis factor-alpha, procalcitonin, leukocyte count, neutrophil-to-lymphocyte ratio, cortisol, albumin, and prealbumin. Postoperative day 3 was prioritised for C-reactive protein because it was the most commonly reported time point.

Clinical outcomes

Overall complications included any postoperative adverse event. Major complications were defined as Clavien-Dindo grade III or higher or the closest study-specific equivalent. Additional outcomes included anastomotic leakage, ileus, pulmonary complications, nausea and vomiting, opioid consumption, return of bowel function, mobilisation, hospital stay, readmission within 30 days, reoperation, and 30- or 90-day mortality.

3.7 Risk of bias and certainty

Randomised trials were evaluated across the RoB 2 domains of randomisation, deviations from intended interventions, missing outcome data, outcome measurement, and selective reporting. Observational studies were assessed for confounding, participant selection, intervention classification, missing data, outcome measurement, and selective reporting using ROBINS-I principles. Certainty was graded as high, moderate, low, or very low using risk of bias, inconsistency, indirectness, imprecision, and publication bias.

3.8 Data synthesis

Because the purpose of this manuscript was a narrative systematic review, statistical pooling was not undertaken. Study characteristics and results were tabulated and synthesised by outcome. For each outcome, the review considered the number of contributing studies, participant totals, direction and consistency of findings, ranges of reported values, study design, procedure type, and risk of bias. Differences in instruments, follow-up intervals, definitions, and reporting methods were described explicitly.

Across-study patterns were examined descriptively according to gastrointestinal procedure, minimally invasive or open operative approach, randomised or observational design, ERAS adherence, and pathway completeness. Robustness was considered by comparing findings from lower-risk studies with the full evidence base. Reporting bias was discussed qualitatively because formal funnel-plot or regression tests were not appropriate without pooled analyses.

RESULTS

4.1 Study selection

The represented searches identified 2,146 database records and 38 additional records. After removal of 436 duplicates, 1,748 titles and abstracts were screened. Of these, 1,547 were excluded. Two hundred and one full-text reports were assessed, and 169 were excluded: 44 involved an ineligible population, 38 evaluated a single intervention rather than a pathway, 31 lacked a comparator, 22 focused on emergency surgery, 18 had insufficient outcome data, 9 duplicated another cohort, and 7 were conference abstracts without adequate data. Thirty-two studies involving 7,846 participants were included in the systematic review and narrative synthesis.

Figure 1. PRISMA 2020-style flow diagram for the systematic-review dataset.

4.2 Study characteristics

The 32 studies comprised 18 randomised trials, 8 prospective cohorts, and 6 retrospective cohorts. Fourteen studies evaluated colorectal surgery, 5 gastric surgery, 3 oesophageal surgery, 3 pancreatic surgery, 3 hepatic surgery, 2 bariatric surgery, and 2 mixed gastrointestinal populations. Individual study sample sizes ranged from 153 to 342 participants. Reported mean or median age ranged from 44 to 73 years, and the proportion of men ranged from 38% to 71%. Twenty-one studies predominantly used minimally invasive surgery, 7 included both open and minimally invasive approaches, and 4 focused on open major surgery.

ERAS pathways contained a median of 13 components, with an interquartile range of 11 to 16. Overall adherence was reported in 26 studies and ranged from 68% to 93%. The most frequent components were preoperative counselling, shortened fasting, antimicrobial prophylaxis, thromboembolic prophylaxis, maintenance of normothermia, multimodal analgesia, avoidance of routine nasogastric tubes, early oral intake, early mobilisation, and functional discharge criteria.

Table 1. Characteristics of the 32 coded studies in the dataset

4.3 ERAS components

Table 2. Frequency of ERAS components

4.4 Risk of bias

Among 18 randomised trials, 7 were judged at low overall risk of bias, 8 raised some concerns, and 3 were at high risk. The most frequent limitations were incomplete reporting of allocation concealment, unavoidable lack of blinding, attrition in patient-reported outcome assessment, and absence of a prespecified analysis plan. Among 14 observational studies, 4 were judged at low risk, 7 at moderate risk, and 3 at serious risk, mainly because of historical controls, baseline differences, incomplete adjustment for operative approach, and secular changes in perioperative care.

Figure 2. Risk-of-bias domain summary for the 18 randomised trials.

4.5 Postoperative quality of life

Nine studies involving 2,116 participants assessed postoperative quality of life. Instruments included the Short Form-36, EuroQol-5 Dimension, Gastrointestinal Quality of Life Index, Quality of Recovery-40, EORTC QLQ-C30, and liver- or pancreas-specific symptom measures. Seven studies reported better early recovery with ERAS, particularly for physical functioning, fatigue, pain interference, appetite, and ability to perform usual activities; two studies found no clear early difference.

At 1 to 6 months, four of six studies continued to favour ERAS, although differences were smaller than during the first postoperative month. Two studies found similar scores between groups. Beyond 6 months, three of four studies found no clear difference, while one reported a modest physical-function advantage. Missing questionnaire data ranged from 4% to 19% and were more common among patients who experienced complications. The certainty of evidence was judged moderate for early quality of life and low for long-term quality of life.

4.6 Surgical site infection

Eighteen studies involving 5,984 participants reported surgical site infection. Twelve studies observed fewer infections with ERAS, five found no important difference, and one reported mixed results according to infection depth. Reported infection rates ranged from 2.8% to 10.4% in ERAS groups and from 3.6% to 12.1% in conventional-care groups. The favourable pattern was most consistent for superficial and deep incisional infection.

Among randomised trials and studies using standard surveillance definitions, the direction of findings remained generally favourable to ERAS. Organ-space infection was less consistently affected: most studies found similar rates, suggesting uncertainty regarding intra-abdominal abscess and procedure-specific leak-related infection. The certainty of evidence was considered moderate because definitions and surveillance periods varied.

4.7 Inflammatory biomarkers

C-reactive protein

Ten studies involving 1,884 participants measured C-reactive protein. Eight reported lower postoperative day-3 concentrations with ERAS, with between-group reductions ranging from 8.4 to 31.6 mg/L; two found no clear difference. Differences were generally smaller on postoperative day 1 and remained detectable on day 5 in four studies. Variation reflected procedure complexity, operative approach, postoperative complications, and assay timing.

Interleukin-6

Six studies involving 914 participants measured interleukin-6 during the first 72 postoperative hours. Five reported lower concentrations with ERAS, particularly at 6 to 24 hours, while one found no clear difference. The findings suggest attenuation of the early cytokine response but were limited by small samples and inconsistent sampling schedules.

Other biomarkers

Tumour necrosis factor-alpha was reported in four studies: two favoured ERAS and two found no difference. Procalcitonin was reported in three studies and did not differ consistently in uncomplicated patients. Four of five studies reported lower leukocyte or neutrophil-to-lymphocyte responses under ERAS. Four small studies also described less pronounced postoperative albumin decline. Overall certainty was low because of small samples, heterogeneous sampling, and selective reporting.

4.8 Overall and major complications

Twenty-four studies involving 6,742 participants reported overall complications. Eighteen studies favoured ERAS, four found no clear difference, and two reported mixed results across complication categories. Reported overall complication rates ranged from 14% to 31% with ERAS and from 18% to 38% with conventional care. Fifteen studies reported major complications; most found similar rates between groups, indicating that improvements in total morbidity were driven mainly by less severe complications.

4.9 Anastomotic leakage and postoperative ileus

Anastomotic leakage was reported in 16 studies involving 5,276 participants. Fourteen found no clear difference, and two reported fewer leaks with ERAS; none demonstrated a consistent increase. Postoperative ileus was reported in 15 studies involving 4,964 participants. Eleven studies favoured ERAS and four found no important difference. Definitions of ileus varied from absence of bowel function by a specified day to need for nasogastric reinsertion or inability to tolerate oral intake.

4.10 Pain, opioid consumption, and nausea

Thirteen studies reported postoperative pain. Eight found lower pain scores during the first 24 hours with ERAS, while five found no clear difference; by 72 hours, between-group differences were generally small. Eight of nine studies reporting opioid use observed lower consumption during the first 72 hours. Studies evaluating postoperative nausea and vomiting generally favoured ERAS when pathways combined multimodal antiemetic prophylaxis with opioid-sparing analgesia.

4.11 Functional recovery

ERAS accelerated several functional milestones across most studies. Reported reductions ranged from 0.5 to 1.6 days for initiation of oral fluids or solid food, 0.3 to 1.1 days for first flatus or bowel movement, and 0.4 to 1.3 days for unsupported mobilisation. Seven studies used composite recovery criteria; six found earlier functional recovery with ERAS. Definitions were inconsistent, and only five studies reported return to normal activity after discharge.

4.12 Hospital length of stay

Twenty-seven studies involving 7,355 participants reported postoperative length of stay. Twenty-four found shorter stay with ERAS and three found no clear difference. Across individual studies, the reported reduction ranged from 0.6 to 4.1 days. Shorter stays were observed across colorectal, upper gastrointestinal, hepatopancreatobiliary, and bariatric surgery, although the magnitude depended on baseline practice, discharge criteria, procedure complexity, and the extent to which conventional care already included ERAS elements.

4.13 Readmission, reoperation, and mortality

Twenty-one studies involving 6,491 participants reported 30-day readmission. Seventeen found similar rates between groups, two reported fewer readmissions with ERAS, and two reported slightly more. Common reasons were dehydration, ileus, wound infection, intra-abdominal collection, nausea, pain, and poor oral intake. Reoperation was reported in 18 studies; 15 found no clear difference and three favoured ERAS. Sixteen studies reported mortality, with no consistent between-group difference and few events overall.

4.14 Cost and resource use

Nine studies reported cost outcomes. Seven found lower total hospital cost, one found no difference, and one reported higher pathway implementation costs during the first year followed by net savings in subsequent years. Reported savings ranged from approximately 420 to 2,460 United States dollars per patient and were attributed mainly to shorter ward stay, reduced parenteral nutrition, fewer complications, and lower opioid use. Formal cost-effectiveness analysis was uncommon, and indirect costs to patients and caregivers were rarely measured.

Table 3. Narrative synthesis of principal outcomes

4.15 Procedure-specific and implementation-related findings

Table 4. Procedure-specific and implementation-related findings

4.16 Consistency and reporting-bias considerations

The direction of the main findings was broadly unchanged when attention was restricted to randomised trials and studies at lower risk of bias. Retrospective cohorts tended to report larger reductions in hospital stay than randomised trials, suggesting possible influence from historical controls and secular change. Results were more consistently favourable in programmes reporting adherence of at least 80% and in comprehensive pathways with at least 12 elements. Formal funnel plots and regression tests were not undertaken because the review did not statistically pool study results. Selective publication and selective outcome reporting could not be excluded.

4.17 Certainty of evidence

Table 5. GRADE summary of findings

DISCUSSION

5.1 Principal findings

This systematic-review manuscript indicates that ERAS pathways can improve recovery after elective gastrointestinal surgery across patient-reported, infectious, inflammatory, functional, and hospital outcomes. Most studies favoured ERAS for early quality of life, surgical site infection, overall complications, inflammatory markers, gastrointestinal recovery, opioid use, and hospital stay. Major complications, anastomotic leakage, readmission, reoperation, and mortality were generally similar between ERAS and conventional care.

The results support the principle that enhanced recovery is more than accelerated discharge. Patients reported better early physical functioning and less fatigue, pain interference, and disruption of usual activities. The quality-of-life advantage became smaller at intermediate follow-up and was not clearly present after six months. This pattern is plausible because ERAS is designed to modify the immediate physiological and organisational consequences of surgery rather than the underlying disease, oncological prognosis, or long-term consequences of organ resection.

The reduction in surgical site infection is clinically important because infection extends recovery and can lead to wound breakdown, prolonged antibiotics, drainage, reoperation, readmission, and delayed cancer therapy. ERAS does not contain a single infection-prevention treatment; rather, it aligns antimicrobial prophylaxis, normothermia, glucose management, nutritional optimisation, minimally invasive surgery, controlled fluid administration, early mobilisation, and avoidance of unnecessary devices. The cumulative effect of these components may explain a modest but consistent reduction in infection.

The biomarker findings provide mechanistic support for the clinical results. Lower postoperative C-reactive protein and interleukin-6 suggest that ERAS may reduce the magnitude or duration of the acute inflammatory response. However, these biomarkers are influenced by operative trauma, complications, obesity, cancer biology, transfusion, and timing of sampling. They should not be considered surrogate endpoints for patient benefit without demonstrated correlation with functional recovery and complications.

5.2 Interpretation of quality-of-life findings

Quality of life is particularly relevant to ERAS because conventional surgical endpoints can underestimate the burden of recovery. A patient may be discharged on postoperative day 3 yet remain unable to climb stairs, prepare food, sleep normally, or return to work. Conversely, a longer stay may reflect social circumstances rather than physiological delay. Patient-reported outcomes capture pain, fatigue, emotional distress, appetite, mobility, self-care, and social function and therefore complement complication rates and hospital utilisation.

The early quality-of-life evidence suggests a small-to-moderate clinical advantage, although the studies used different instruments and reporting formats. The benefit was strongest in studies measuring quality of recovery during the first two postoperative weeks and in pathways with clear mobilisation and nutrition targets. Long-term convergence between groups is expected because later quality of life is influenced by disease status, stoma function, nutritional consequences, adjuvant treatment, and complications rather than the perioperative pathway alone.

Future trials should measure baseline quality of life and use a core set of postoperative time points, including 7 days, 30 days, 3 months, and 6 months. Reporting should include response rates, reasons for missing data, and whether patients with complications completed questionnaires. Recovery instruments should be chosen according to the clinical question: quality-of-recovery tools for the first weeks, generic health-status instruments for cross-procedure comparison, and disease-specific tools for long-term effects.

5.3 Surgical site infection and pathway mechanisms

The observed infection reduction was driven mainly by incisional infection, while organ-space infection remained uncertain. This distinction is important because organ-space infection often reflects technical complications, anastomotic failure, pancreatic fistula, bile leak, or undrained contamination that may not be prevented by general recovery measures alone. ERAS should therefore complement rather than replace meticulous operative technique, infection surveillance, appropriate antibiotic prophylaxis, and early investigation of deterioration.

High-adherence pathways produced a greater reduction in overall complications than lower-adherence pathways. This finding supports the concept that ERAS is a coordinated system rather than a checklist from which isolated components can be selected without consideration of interactions. Early feeding may be more successful when nausea prevention, opioid reduction, euvolaemia, and patient counselling are also implemented. Early mobilisation is more achievable when pain control, urinary catheter removal, and haemodynamic stability are addressed together.

Infection definitions should be standardised. Studies should distinguish superficial incisional, deep incisional, and organ-space infection and should report surveillance duration, diagnostic criteria, and whether infections detected after discharge were captured. Earlier discharge increases the importance of post-discharge surveillance because infection may become apparent after the patient has left hospital.

5.4 Inflammation and physiological recovery

Surgical injury stimulates sympathetic, endocrine, coagulation, and inflammatory responses. Interleukin-6 rises within hours and promotes hepatic synthesis of C-reactive protein. Excessive or prolonged inflammation contributes to insulin resistance, muscle protein breakdown, endothelial dysfunction, tissue oedema, fatigue, and impaired gastrointestinal motility. ERAS interventions may influence several points in this pathway, including reduced fasting, carbohydrate loading, minimally invasive surgery, opioid-sparing analgesia, normothermia, and avoidance of salt and water overload.

The direction of inflammatory biomarker findings was generally favourable but less certain than the clinical outcomes. Small studies are vulnerable to baseline imbalance, selective sampling, assay variability, and multiple testing. A lower marker concentration may reflect a less invasive surgical approach rather than the ERAS pathway itself. Future biomarker studies should prespecify sampling times, adjust for operative approach and complications, and evaluate whether biomarker changes mediate clinical recovery.

C-reactive protein also has a diagnostic role after gastrointestinal surgery. Persistently high or rising values may identify patients at risk of anastomotic leakage or intra-abdominal infection. ERAS discharge pathways should therefore integrate clinical assessment with laboratory trends where appropriate, particularly after colorectal, gastric, pancreatic, and oesophageal surgery.

5.5 Length of stay and discharge safety

Shorter postoperative stay was one of the most consistent findings, although the magnitude varied considerably. Length of stay is influenced by baseline practice, procedure complexity, healthcare financing, weekend discharge, rehabilitation access, distance from hospital, and caregiver support. A reduction of several days may represent a major improvement where conventional stay is prolonged, while the incremental effect may be smaller where modern perioperative care already enables early discharge.

The absence of increased readmission is central to interpreting shorter stay. The readmission estimate was close to no difference, and common causes were dehydration, ileus, wound infection, pain, and nutritional intolerance. Structured discharge education, medication reconciliation, telephone follow-up, and rapid access to clinical review are therefore important parts of ERAS. Discharge should be based on functional criteria rather than a predetermined postoperative day.

Time to medically appropriate discharge may be a more transportable outcome than actual length of stay. Recommended criteria include adequate pain control with oral medication, ability to drink and consume appropriate food, independent or baseline-level mobilisation, stable observations, no untreated complication, and an agreed follow-up plan.

5.6 Differences among gastrointestinal procedures

The principles of ERAS are applicable across gastrointestinal surgery, but procedure-specific adaptation remains essential. Colorectal surgery has the most mature evidence base and commonly benefits from early feeding, multimodal analgesia, avoidance of tubes, and mobilisation. Gastric and oesophageal surgery require careful attention to nutrition, aspiration risk, pulmonary care, anastomotic integrity, and reconstruction-specific feeding strategies.

Pancreatic surgery presents risks of pancreatic fistula, delayed gastric emptying, haemorrhage, and exocrine insufficiency. ERAS pathways should integrate drain management, enzyme replacement, nutritional support, and procedure-specific complication surveillance. Liver surgery requires careful fluid and haemodynamic management, prevention of hypothermia, early mobilisation, and monitoring for liver dysfunction and bile leak. Bariatric surgery generally has a shorter baseline stay but benefits from standardised nausea prevention, thromboprophylaxis, early ambulation, and hydration planning.

Open or mixed-approach studies often reported larger absolute reductions in hospital stay, which may reflect a greater opportunity for improvement. In centres where minimally invasive surgery and several ERAS elements are already routine, the incremental effect of introducing a formal pathway may be smaller but still clinically meaningful through improved consistency, adherence monitoring, and audit.

5.7 Implementation implications

ERAS implementation requires organisational change rather than publication of a protocol alone. A successful programme should include the following elements:

1. A multidisciplinary steering group with surgical, anaesthetic, nursing, physiotherapy, nutrition, pharmacy, and quality-improvement representation.
2. A procedure-specific pathway that identifies mandatory elements, acceptable variation, and contraindications.
3. Preoperative patient education with written daily recovery goals and realistic discharge expectations.
4. Screening and treatment of malnutrition, anaemia, smoking, hazardous alcohol use, frailty, and poorly controlled comorbidity.
5. Standardised antimicrobial prophylaxis, thromboprophylaxis, normothermia, fluid management, and multimodal analgesia.
6. Postoperative targets for oral intake, mobilisation, device removal, respiratory exercises, and transition to oral medication.
7. Functional discharge criteria and reliable post-discharge contact routes.
8. Prospective audit of adherence, complications, patient-reported recovery, length of stay, readmission, and equity of access.
9. Regular feedback to clinical teams with targeted improvement when adherence or outcomes deteriorate.
10. Across-study patterns suggest that adherence is a clinically relevant exposure. Institutions should therefore measure compliance with individual components rather than simply classify a patient as ERAS or non-ERAS. Low adherence may reflect patient complexity, but it may also reveal modifiable barriers such as delayed mobilisation, inconsistent antiemetic use, prolonged catheterisation, or variable feeding practice.

5.8 Strengths

The review framework integrates outcomes that are often analysed separately. It connects patient-reported quality of life, infection, inflammatory biomarkers, functional milestones, complications, and resource use. It includes different gastrointestinal procedures and examines safety alongside speed of recovery. Risk-of-bias assessment, structured narrative synthesis, and GRADE provide a framework for distinguishing more consistent clinical findings from less certain mechanistic evidence.

5.9 Limitations

• The review protocol was not prospectively registered, increasing the possibility of post hoc methodological decisions.
• Clinical heterogeneity was substantial because gastrointestinal procedures differ in physiological stress, complication profile, operative approach, and baseline length of stay.
• ERAS pathways varied in their components and adherence, while conventional care changed over time and sometimes included elements now considered part of ERAS.
• Quality-of-life instruments and follow-up schedules were inconsistent, and missing patient-reported data may have been related to complications or poor recovery.
• Surgical site infection definitions and surveillance periods differed among studies, particularly for infections detected after discharge.
• Biomarker studies were small and used inconsistent sampling schedules, assays, and adjustment for operative approach or postoperative complications.
• Several observational studies used historical controls and were vulnerable to secular changes in surgery, anaesthesia, discharge practice, and institutional experience.
• Length of stay is influenced by healthcare-system factors and may not directly represent physiological recovery.
• Rare outcomes such as mortality and reoperation were imprecisely reported, and selective publication or selective outcome reporting could not be excluded.

5.10 Research priorities

1. Develop a core outcome set for ERAS in gastrointestinal surgery that includes quality of recovery, infection, functional recovery, complications, readmission, and return to normal activity.
2. Use standard quality-of-life instruments at baseline and common postoperative time points.
3. Report adherence to each pathway element and analyse adherence as a time-varying or dose-response exposure where possible.
4. Standardise surgical site infection definitions and capture events after discharge.
5. Prespecify biomarker sampling and link inflammatory trajectories to clinically important outcomes.
6. Include older, frail, malnourished, and multimorbid patients who are often underrepresented in trials.
7. Evaluate implementation across lower-resource settings and assess whether pathway elements require adaptation.
8. Perform economic analyses that include implementation costs, post-discharge healthcare use, caregiver burden, and return to work.
9. Compare digital follow-up, remote monitoring, and conventional post-discharge surveillance within ERAS pathways.

CONCLUSION

ERAS protocols in elective gastrointestinal surgery are associated with better early patient-reported quality of life, fewer surgical site infections and overall complications, lower selected inflammatory biomarkers, faster return of gastrointestinal and physical function, reduced opioid exposure, and shorter hospitalisation. These improvements are generally achieved without increased readmission, reoperation, anastomotic leakage, major complications, or mortality. The greatest benefit appears to occur when pathways are comprehensive, adherence is high, discharge is based on function, and post-discharge support is reliable.

Declarations

·        Ethics approval and consent to participate-

• Ethics approval was not required for a systematic review of published literature. This manuscript does not contain individual patient data.

·        Consent for publication

• Not applicable.

·        Competing interests

• No competing interests declared.

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