Major gastrointestinal surgery produces a coordinated physiological stress response characterised by neuroendocrine activation, inflammation, insulin resistance, protein catabolism, fluid retention, impaired gastrointestinal motility, pain, fatigue, and temporary reduction in functional capacity. Although this response is initially adaptive, excessive or prolonged activation may delay recovery and contribute to pulmonary complications, ileus, infection, thromboembolism, loss of muscle mass, and extended hospitalisation.

Enhanced Recovery After Surgery, commonly abbreviated as ERAS, is a multimodal perioperative-care model developed to reduce avoidable variation in surgical practice and attenuate the physiological consequences of major surgery. ERAS pathways combine preoperative counselling and optimisation, reduced fasting, selective carbohydrate loading, standardised anaesthesia, opioid-sparing analgesia, maintenance of normothermia and euvolaemia, avoidance of unnecessary tubes and drains, early oral nutrition, early mobilisation, thromboprophylaxis, and structured discharge planning.¹˒²

The concept was initially developed and most extensively studied in elective colorectal surgery. Early fast-track programmes demonstrated that several traditional practices, including prolonged fasting, routine nasogastric decompression, delayed feeding, excessive intravenous fluid administration, and extended bed rest, were not necessary for uncomplicated recovery.³ Subsequent ERAS Society guidelines formalised these principles and provided procedure-specific recommendations.²

ERAS should not be understood as a single intervention. It is a coordinated pathway whose effectiveness depends on the interaction of multiple elements and the degree of adherence achieved by the surgical, anaesthetic, nursing, nutritional, physiotherapy, and patient teams. The individual contribution of each component is difficult to isolate because pathway elements are implemented simultaneously.

Meta-analyses in elective colorectal surgery have generally found that ERAS shortens hospital stay and reduces overall morbidity without significantly increasing readmission.⁴˒⁵ Similar findings have been reported in gastric, hepatic, pancreatic, oesophageal, and bariatric surgery, although the maturity and consistency of the evidence vary by specialty.⁶˒⁷

Length of stay, however, is not sufficient as the sole measure of recovery. Earlier discharge may reflect genuine functional recovery, changes in institutional practice, or transfer of care burden from hospital to patients and families. Evaluation should therefore include patient-reported quality of life, complications, infection, readmission, functional recovery, and biological measures of surgical stress.

Postoperative quality of life is especially relevant because patients may experience fatigue, pain, anxiety, sleep disruption, nutritional difficulty, and reduced physical function after leaving hospital. ERAS could improve quality of life through better pain control, earlier mobilisation, reduced complications, and faster restoration of nutrition. Conversely, accelerated discharge or early feeding could theoretically increase discomfort or patient concern. Available studies generally suggest that ERAS does not adversely affect satisfaction or quality of life and may accelerate the return to normal activities, although study instruments and assessment times differ substantially.⁸

Surgical-site infection is an important complication after gastrointestinal surgery because intestinal procedures involve exposure to endogenous microorganisms, and many patients have malignancy, malnutrition, obesity, diabetes, or immunosuppression. ERAS includes several measures that may reduce infection risk, such as antimicrobial prophylaxis, normothermia, glycaemic control, appropriate oxygenation, early mobilisation, reduced catheter exposure, and shorter hospitalisation. However, ERAS pathways do not replace established infection-prevention bundles, and reductions in infection may partly reflect concurrent improvements in surgical technique or institutional quality systems.

The postoperative inflammatory response provides a biological framework through which ERAS may influence recovery. C-reactive protein, interleukin-6, tumour necrosis factor-α, procalcitonin, neutrophil-to-lymphocyte ratio, and other biomarkers rise after major surgery. The magnitude and persistence of this response may reflect tissue injury, operative stress, infection, or anastomotic complications. Studies in gastric and colorectal surgery have reported lower postoperative CRP and IL-6 concentrations under ERAS pathways, although biomarker findings are affected by surgical approach, operative duration, anaesthetic management, and timing of measurement.⁶˒⁹

Inflammatory biomarkers also have a second clinical role. Even when an ERAS pathway enables early discharge, persistently high or rising CRP, procalcitonin, IL-6, or related markers may identify patients with occult anastomotic leakage, intra-abdominal infection, or another major complication. Biomarker monitoring may therefore support safe implementation rather than merely demonstrate attenuation of stress.

A comprehensive synthesis is needed because earlier reviews have frequently focused on a single procedure or outcome. This review therefore examines patient-centred, infectious, biological, and conventional clinical outcomes across elective gastrointestinal surgical specialties.

Rationale

The benefits of ERAS are often summarised as reduced length of stay. This may undervalue patient-centred and biological outcomes and may encourage an overly narrow interpretation of success. A pathway that produces earlier discharge but worsens quality of life, infection, readmission, or complications would not represent meaningful recovery.

The present review evaluates ERAS through four interrelated domains: the patient’s perceived recovery and quality of life; surgical-site and healthcare-associated infection; the postoperative inflammatory response; and conventional clinical outcomes such as bowel recovery, morbidity, readmission, reoperation, mortality, and hospital stay.

Review Question

Among adults undergoing elective gastrointestinal surgery, how do multimodal ERAS protocols compare with conventional perioperative care in relation to postoperative quality of life, surgical-site infection, inflammatory biomarkers, gastrointestinal recovery, hospital stay, complications, readmission, reoperation, and mortality?

Objectives

The review aimed to determine whether ERAS improves postoperative quality of life and functional recovery, reduces surgical-site infection and overall morbidity, attenuates inflammatory biomarkers, accelerates gastrointestinal recovery, shortens hospital stay, and maintains acceptable readmission, reoperation, and mortality rates. It also examined whether greater protocol adherence was associated with improved outcomes and whether effects differed among colorectal, gastric, oesophageal, pancreatic, hepatic, and bariatric procedures.

MATERIALS AND METHODS

Review Design and Reporting

This systematic review was designed and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. ¹⁰˒¹¹

Protocol and Registration

The review was not prospectively registered in PROSPERO, and no formal protocol was publicly deposited before screening. The research question, eligibility criteria, databases, principal outcomes, extraction variables, quality-assessment approach, and synthesis plan were defined before completion of study selection. The absence of prospective registration is acknowledged as a limitation because it may increase the risk of protocol deviation or selective reporting.

Information Sources

PubMed/MEDLINE, Embase, Scopus, Web of Science, CINAHL, and the Cochrane Library were searched from database inception to January 31, 2026. Supplementary searches were conducted through Google Scholar, ClinicalTrials.gov, citation tracking, and manual screening of references from eligible studies and relevant systematic reviews.

Search Strategy

The search combined controlled vocabulary and free-text terms relating to enhanced recovery and gastrointestinal surgery. Representative terms included “enhanced recovery after surgery,” “ERAS,” “enhanced recovery programme,” “enhanced recovery pathway,” “fast-track surgery,” “multimodal perioperative care,” “colorectal surgery,” “gastrectomy,” “gastric surgery,” “oesophagectomy,” “pancreatectomy,” “hepatectomy,” “bariatric surgery,” and “gastrointestinal surgery.”

Outcome terms included “quality of life,” “patient-reported outcome,” “fatigue,” “functional recovery,” “surgical-site infection,” “wound infection,” “healthcare-associated infection,” “C-reactive protein,” “interleukin-6,” “tumour necrosis factor,” “procalcitonin,” “inflammatory response,” “length of stay,” “ileus,” “bowel function,” “complication,” “readmission,” “reoperation,” and “mortality.”

Search syntax was adapted to each database. No geographical restriction was applied. English-language full-text studies were included.

Eligibility Criteria

Studies were eligible when they involved adults undergoing elective gastrointestinal surgery and compared a multimodal ERAS, enhanced recovery, or fast-track pathway with conventional perioperative care. Eligible procedures included colorectal resection, gastrectomy, oesophagectomy, pancreatic resection, hepatectomy, and bariatric operations.

Randomised controlled trials, prospective comparative cohorts, retrospective comparative cohorts, multicentre implementation studies, and controlled before-and-after studies were included. Studies were required to report at least one prespecified outcome: quality of life, patient satisfaction, fatigue, functional recovery, surgical-site infection, inflammatory biomarkers, return of gastrointestinal function, hospital stay, complications, readmission, reoperation, or mortality.

Studies evaluating only one isolated component, such as a single analgesic, carbohydrate drink, nutritional supplement, or minimally invasive technique, were excluded unless that component was explicitly evaluated within a broader ERAS pathway. Emergency surgery, paediatric surgery, transplantation, non-gastrointestinal surgery, uncontrolled case series, narrative reviews, protocols, and conference abstracts without sufficient data were excluded.

Study Selection

All records were imported into reference-management software. Duplicate records were removed electronically and verified manually. Two reviewers independently screened titles and abstracts. Full-text reports were obtained when either reviewer considered the record potentially eligible.

Two reviewers independently assessed eligibility at full-text level. Disagreements were resolved through discussion and, when necessary, consultation with a third reviewer. Reasons for exclusion were recorded systematically.

Data Extraction

A standardised form was used to extract first author, publication year, country, study design, surgical procedure, sample size, patient characteristics, operative approach, principal ERAS components, protocol adherence, comparator, quality-of-life instrument, timing of assessment, infection outcomes, biomarker type and sampling time, length of stay, bowel recovery, complications, readmission, reoperation, mortality, and study limitations.

Data were independently extracted by two reviewers and cross-checked. Disagreements were resolved by consensus.

Outcomes

The primary outcomes were postoperative quality of life, surgical-site infection, and inflammatory biomarkers. Quality-of-life outcomes included validated global or disease-specific scores, physical function, fatigue, pain, return to usual activity, and satisfaction. Surgical-site infection included superficial incisional, deep incisional, and organ-space infection where reported. Biomarkers included CRP, IL-6, TNF-α, procalcitonin, white-cell count, neutrophil-to-lymphocyte ratio, and related measures.

Secondary outcomes included postoperative length of stay, time to first flatus or bowel movement, time to oral intake, postoperative ileus, overall and major complications, anastomotic leakage, pulmonary complications, urinary infection, readmission, reoperation, mortality, and cost.

Methodological Quality Assessment

Randomised controlled trials were assessed with the Cochrane Risk of Bias 2 tool. Non-randomised comparative studies were evaluated using ROBINS-I or the Newcastle–Ottawa Scale, according to design. Implementation studies were additionally examined for completeness of ERAS definition, adherence measurement, temporal bias, concurrent changes in surgical practice, and adjustment for case mix.

Quality-of-life studies were examined for use of validated instruments, baseline measurement, completeness of follow-up, handling of missing questionnaires, and timing of assessment. Biomarker studies were assessed for standardisation of sample collection, timing, assay method, surgical approach, and exclusion of patients with established postoperative infection at the time of measurement.

Data Synthesis

Considerable heterogeneity was expected because the studies involved different operations, ERAS protocols, levels of compliance, surgical approaches, quality-of-life instruments, biomarker schedules, discharge criteria, and complication definitions. Findings were therefore synthesised narratively.

Evidence was organised by outcome and surgical specialty. Where available, the direction and consistency of effects were compared rather than combining clinically dissimilar estimates into a single pooled value.

RESULTS

PRISMA Study Selection

The electronic database search identified 3,328 records. PubMed/MEDLINE contributed 924 records, Embase contributed 806, Scopus contributed 684, Web of Science contributed 512, CINAHL contributed 196, and the Cochrane Library contributed 206. An additional 98 records were identified through Google Scholar, ClinicalTrials.gov, citation tracking, and manual reference-list screening. The total number of records identified was 3,426.

After removal of 914 duplicates, 2,512 unique records remained for title and abstract screening. A total of 2,266 records were excluded because they did not evaluate gastrointestinal surgery, did not compare a multimodal ERAS pathway with conventional care, examined emergency surgery or another ineligible population, or represented reviews, protocols, editorials, or clearly unrelated reports.

Full-text retrieval was attempted for 246 reports. Twelve reports could not be retrieved, leaving 234 full-text reports for eligibility assessment. Of these, 204 were excluded. Fifty-one evaluated only a single perioperative intervention rather than a complete ERAS pathway, 39 did not include an eligible comparator, 32 involved non-elective or non-gastrointestinal surgery, 27 did not report a prespecified outcome, 21 were systematic or narrative reviews without original data, 14 represented duplicate or overlapping populations, 11 had insufficient methodological information, and nine were protocols or conference reports without usable results.

Thirty studies met the eligibility criteria and were included in the qualitative synthesis. No quantitative meta-analysis was undertaken because of substantial clinical and methodological heterogeneity.

Figure 1. PRISMA 2020 flow diagram showing identification, screening, eligibility assessment, and inclusion of studies evaluating ERAS protocols in elective gastrointestinal surgery.

Characteristics of Included Studies

The included studies comprised randomised controlled trials, prospective comparative studies, retrospective cohorts, controlled before-and-after evaluations, and multicentre implementation studies. Colorectal surgery accounted for the largest proportion of the evidence, followed by gastric surgery, hepatic surgery, pancreatic surgery, oesophagectomy, and bariatric surgery.

The size and content of ERAS pathways differed. Most included preoperative counselling, minimisation of fasting, standardised anaesthesia, opioid-sparing analgesia, avoidance of excessive fluid administration, early catheter removal, early oral feeding, and mobilisation. Fewer studies reported formal prehabilitation, smoking cessation, anaemia correction, carbohydrate loading, or post-discharge monitoring.

Table 1. Characteristics and principal findings of included studies

Methodological Quality

Randomised colorectal trials were generally of moderate methodological quality. Blinding of patients and clinical teams was rarely possible, creating risk of performance bias. Discharge decisions were potentially influenced by knowledge of allocation, particularly when length of stay was the primary outcome.

Non-randomised implementation studies were vulnerable to temporal confounding. Improvements attributed to ERAS may have occurred alongside increasing use of laparoscopy, revised antimicrobial prophylaxis, infection-prevention bundles, better anaesthetic techniques, and institutional quality-improvement programmes.

Quality-of-life studies frequently had incomplete follow-up, variable measurement timing, and heterogeneity in instruments. Biomarker studies were often small and differed in assay methods and postoperative sampling schedules.

A major reporting limitation was incomplete description of ERAS compliance. Some studies classified patients according to pathway availability rather than the proportion of pathway elements actually delivered.

Postoperative Quality of Life and Patient-Reported Recovery

Quality of life typically declined during the early postoperative period in both ERAS and conventional-care groups because of pain, fatigue, reduced appetite, sleep disruption, and temporary functional limitation. Recovery occurred progressively over subsequent weeks.

The available evidence did not demonstrate that accelerated feeding, mobilisation, or discharge caused deterioration in overall quality of life. Several studies reported earlier improvement in fatigue, physical function, or return to daily activities after ERAS. However, long-term global quality-of-life scores were frequently similar between groups after the early recovery period.⁸

The quality-of-life effect appeared to be greatest during the first days and weeks after surgery rather than several months later. This is biologically plausible because ERAS primarily modifies perioperative stress and immediate recovery rather than the long-term consequences of cancer, adjuvant treatment, or chronic comorbidity.

Pain findings were generally favourable or neutral. Opioid-sparing multimodal analgesia reduced nausea, sedation, and ileus, but some early fast-track studies reported concern about pain after open surgery when epidural or systemic analgesia was withdrawn early. Effective regional anaesthesia, non-opioid analgesics, and structured reassessment were important for avoiding undertreatment.

Patient satisfaction was usually similar or higher with ERAS. Preoperative education appeared to reduce uncertainty by explaining early feeding, mobilisation, expected discharge criteria, and the patient’s role in recovery. Patients were more likely to view early discharge positively when they had clear contact pathways and understood warning symptoms.

The evidence did not support using length of stay as a surrogate for patient-centred recovery without additional assessment. A patient discharged early may still experience substantial fatigue or require family assistance. Quality-of-life measurement and post-discharge follow-up should therefore remain integral to ERAS evaluation.

Surgical-Site Infection and Other Healthcare-Associated Infections

Several colorectal implementation studies reported lower surgical-site infection rates after ERAS introduction. Potential explanations included reduced hypothermia, better glycaemic control, standardised antimicrobial prophylaxis, improved oxygenation, reduced fluid overload, earlier mobilisation, shorter catheter exposure, and reduced length of hospital stay.¹²˒¹³

Large multicentre observational data have also suggested reductions in superficial and deep SSI after implementation of an ERAS programme. These findings are clinically important, but they should be interpreted cautiously because infection-prevention practices often improve concurrently with ERAS implementation.

Randomised trials were less consistently powered to detect SSI differences because infection was usually a secondary outcome and event numbers were small. Consequently, the absence of a statistically significant difference in individual trials should not be interpreted as evidence that ERAS has no infection-related effect.

ERAS does not eliminate the need for dedicated SSI-prevention measures. Appropriate antimicrobial selection and timing, skin preparation, maintenance of normothermia, glycaemic control, bowel preparation according to procedure and institutional policy, wound protection, and sterile surgical technique remain essential.

Organ-space infection and anastomotic leakage were generally not increased by ERAS. Early feeding was not consistently associated with increased leakage. However, symptoms of intra-abdominal complications may become evident after discharge, making patient education, rapid access to reassessment, and biomarker-informed follow-up important.

Reductions in urinary infection were reported in some implementation studies and may reflect earlier urinary-catheter removal. Pulmonary infection may be reduced through mobilisation, improved analgesia, avoidance of excessive sedation, and respiratory physiotherapy. The effects on infection therefore arise from multiple pathway components rather than a single antimicrobial intervention.

Inflammatory Biomarkers and the Surgical Stress Response

Major gastrointestinal surgery triggers release of inflammatory cytokines and acute-phase proteins. IL-6 rises rapidly after tissue injury and contributes to hepatic production of CRP. TNF-α, IL-1β, procalcitonin, white-cell count, neutrophil-to-lymphocyte ratio, and other biomarkers may also change.

Studies in gastric surgery reported lower CRP and IL-6 concentrations during the early postoperative period under ERAS pathways.⁶˒⁹ Reduced inflammatory responses may reflect shorter fasting, lower opioid exposure, more precise fluid management, minimally invasive surgery, maintained normothermia, earlier nutrition, and reduced postoperative complications.

The interpretation of biomarkers is complicated by operative approach. Laparoscopic surgery independently reduces tissue injury and inflammatory activation compared with open surgery. Studies that combine laparoscopy with ERAS may therefore overestimate the effect attributable to the care pathway itself unless operative approach is balanced.

Biomarker timing is also important. IL-6 rises early, whereas CRP typically peaks later. A single postoperative measurement may not adequately represent the trajectory. Studies using different postoperative days cannot be compared directly.

Inflammatory markers also assist in complication detection. In gastric and colorectal surgery, persistently elevated or increasing CRP and procalcitonin may indicate anastomotic leakage, intra-abdominal infection, or another major complication. IL-1β and TNF-α have also been evaluated in this context.

The use of ERAS should not result in dismissal of abnormal inflammatory markers simply because a patient appears clinically suitable for discharge. Biomarker trends may provide additional safety information, especially when discharge occurs before the conventional peak period for some complications.

The evidence therefore supports two related conclusions. ERAS may attenuate the expected postoperative inflammatory response, but unexpectedly high or persistent inflammation remains clinically important and should prompt further assessment.

Gastrointestinal Recovery

Earlier return of gastrointestinal function was among the most consistent findings. ERAS pathways reduced time to first flatus, bowel movement, and tolerance of oral intake across colorectal and gastric studies.

Several components may contribute. Avoidance of excessive intravenous fluids reduces bowel-wall oedema, opioid-sparing analgesia limits pharmacological ileus, early feeding stimulates gastrointestinal function, mobilisation supports recovery, and avoidance of routine nasogastric tubes reduces discomfort and may facilitate oral intake.

Early oral nutrition was generally feasible after elective gastrointestinal surgery. The evidence did not show a consistent increase in anastomotic leakage or aspiration when patients were appropriately selected and monitored.

Postoperative ileus remained a clinically important complication and was not eliminated by ERAS. Procedure complexity, open surgery, opioid exposure, fluid overload, electrolyte abnormalities, and intra-abdominal complications remained relevant risk factors.

Length of Hospital Stay and Functional Recovery

ERAS consistently shortened postoperative hospital stay across colorectal, gastric, hepatic, pancreatic, and bariatric surgery. Meta-analyses in colorectal surgery reported reductions without a corresponding increase in readmission, while gastric-surgery evidence similarly demonstrated shorter stay and lower cost.⁴–⁶

Length of stay is influenced by discharge criteria, local resources, reimbursement, availability of home support, and institutional culture. It should therefore be interpreted as a healthcare-process outcome rather than a direct biological measure.

Functional recovery is a more meaningful concept and includes adequate pain control with oral medication, tolerance of oral nutrition, independent or baseline mobility, recovery of gastrointestinal function, absence of untreated complications, and confidence in post-discharge management.

Some studies discharged patients according to fixed time targets, while others used objective recovery criteria. Criterion-based discharge is preferable because it reduces pressure to discharge patients before adequate recovery.

Overall Morbidity and Major Complications

Overall postoperative morbidity was reduced or unchanged in most included studies. Colorectal meta-analyses reported lower overall complications without increased readmission.⁴˒⁵ The effect was most consistent for non-surgical complications such as pulmonary problems, urinary infection, nausea, and prolonged ileus.

The effect on major surgical complications was less certain because events such as anastomotic leakage, intra-abdominal abscess, pancreatic fistula, or post-hepatectomy liver failure were relatively uncommon and strongly influenced by operative technique and patient risk.

ERAS is not a substitute for technically sound surgery. The pathway supports recovery but cannot compensate for inadequate anastomosis, haemorrhage, organ injury, or failure to recognise deterioration.

In pancreatic surgery, concerns have included delayed gastric emptying, pancreatic fistula, and the safety of early drain removal. Available comparative evidence indicates that selected ERAS elements can be implemented safely, but procedure-specific risk assessment remains essential.

In hepatic surgery, ERAS reduced hospital stay and supported earlier mobilisation and feeding without increasing mortality or readmission. Fluid management and avoidance of unnecessary tubes were particularly relevant.

In oesophageal surgery, respiratory complications, anastomotic leakage, and nutritional challenges remain major determinants of outcome. Evidence supports selected ERAS components, but the pathway must account for the complexity and high morbidity of oesophagectomy.

Readmission, Reoperation, and Mortality

A central safety concern is that shorter hospitalisation could increase readmission. Most randomised trials and meta-analyses did not demonstrate a significant increase in readmission after ERAS.⁴–⁶

Readmission rates depend on the definition and follow-up period used. Thirty-day readmission is preferable to readmission to the index hospital only because patients may present elsewhere.

Reoperation was generally similar between ERAS and conventional care groups. This supports the conclusion that ERAS does not increase major surgical failure when appropriately implemented.

Mortality was low in most elective-surgery studies, limiting statistical power. No consistent evidence suggested increased short-term mortality. Large observational studies and specialty-specific reviews generally supported the safety of ERAS.

Protocol Adherence

Protocol adherence emerged as an important modifier of outcome. Multicentre colorectal studies demonstrated that greater adherence was associated with fewer complications, shorter stay, and improved recovery.¹⁴

Adherence is not all-or-none. A patient may be enrolled in an ERAS programme but receive only some components. Studies that classify all post-implementation patients as fully treated may underestimate or obscure dose-response relationships.

Some components are easier to deliver than others. Preoperative counselling and antibiotic prophylaxis often achieve high compliance, whereas early mobilisation, oral intake targets, opioid avoidance, and timely removal of intravenous fluids or urinary catheters may be more difficult.

Audit and feedback are therefore central to ERAS. Teams should measure both clinical outcomes and delivery of individual pathway elements. A decline in adherence over time may reduce effectiveness even when the programme remains nominally active.

Differences Across Gastrointestinal Specialties

Colorectal Surgery

Colorectal surgery had the strongest evidence, including randomised trials, meta-analyses, and multicentre adherence studies. The results consistently supported shorter stay, faster bowel recovery, and reduced or unchanged morbidity. Evidence for lower SSI was favourable, particularly in quality-improvement cohorts.

Gastric Surgery

Gastric-surgery studies demonstrated shorter stay, earlier oral intake, reduced inflammatory responses, and no consistent increase in morbidity or readmission. Meta-analytic evidence suggested lower postoperative CRP and IL-6.⁶

The applicability of findings may depend on the extent of gastrectomy, reconstruction, cancer stage, and laparoscopic versus open surgery.

Pancreatic Surgery

ERAS after pancreaticoduodenectomy or distal pancreatectomy was feasible and generally shortened stay. The evidence was more observational than randomised. Pancreatic fistula, delayed gastric emptying, and drain management required procedure-specific protocols.

Hepatic Surgery

Enhanced recovery after liver resection improved functional recovery and shortened hospital stay. Fluid management, early feeding, mobilisation, and analgesia were central components. Mortality and readmission were not increased in available comparative studies.

Oesophageal Surgery

Oesophagectomy has a high physiological burden and complication rate. ERAS pathways supported earlier mobilisation, respiratory rehabilitation, and standardisation of nutrition. The evidence was less mature and more heterogeneous than in colorectal surgery.

Bariatric Surgery

ERAS facilitated early mobilisation and discharge after bariatric procedures. Safety depended on appropriate patient selection, thromboprophylaxis, nausea control, analgesia, and clear post-discharge instructions. Meta-analytic evidence supports shorter recovery without increased major complications.

Proposed Mechanism of Benefit

ERAS may improve recovery through several interacting pathways. Preoperative information reduces anxiety and improves participation. Reduced fasting and selected carbohydrate loading limit metabolic depletion and insulin resistance. Opioid-sparing analgesia reduces sedation, nausea, respiratory depression, and ileus. Goal-directed or balanced fluid therapy reduces oedema and cardiopulmonary stress. Normothermia and glycaemic control support immune and wound function.

Early feeding provides substrate for recovery and stimulates gastrointestinal motility. Early mobilisation reduces deconditioning, thromboembolic risk, and pulmonary complications. Avoidance of unnecessary drains, nasogastric tubes, and urinary catheters reduces discomfort and device-associated infection.

These elements collectively reduce the physiological and psychological barriers to recovery. The benefit depends on coordinated delivery rather than any one component.

Figure 2. Integrated pathway through which ERAS components may influence surgical stress, infection, functional recovery, quality of life, and clinical outcomes.

DISCUSSION

This review found that ERAS protocols improve short-term recovery after elective gastrointestinal surgery. The most consistent effects were shorter hospital stay, earlier gastrointestinal recovery, and lower or unchanged overall morbidity. These benefits were demonstrated most convincingly in colorectal surgery and supported by increasing evidence in gastric, hepatic, pancreatic, oesophageal, and bariatric procedures.

The review also supports the biological plausibility of ERAS. Lower postoperative CRP and IL-6 in several gastric and colorectal studies suggest that multimodal perioperative optimisation may attenuate the inflammatory response. These findings should not be attributed to ERAS alone without considering laparoscopy, operative duration, anaesthetic technique, and complications. Nevertheless, the consistency of the direction of effect suggests that reducing perioperative stress influences postoperative biology.

Quality-of-life evidence was reassuring but less definitive. ERAS did not appear to worsen patient satisfaction or quality of life, and several studies suggested earlier improvement in fatigue, mobility, or return to activity. Long-term differences were usually limited because recovery converged over time and was influenced by cancer treatment, comorbidity, and disease prognosis.

Surgical-site infection findings were favourable but methodologically challenging. Infection reduction was more evident in large implementation studies than in individual randomised trials. This may reflect greater statistical power, but it may also reflect concurrent infection-prevention initiatives. ERAS should therefore be regarded as complementary to, rather than a replacement for, SSI-prevention bundles.

The absence of increased readmission is important because it supports the safety of shorter hospitalisation. However, readmission alone cannot capture post-discharge burden. Telephone calls, emergency visits, family caregiving, community nursing, and delayed presentation at another hospital should be considered in future evaluations.

The association between greater ERAS adherence and better outcomes supports a dose-response relationship. It also highlights a weakness of studies that define exposure according to programme era rather than actual care received. Future research should report adherence to each component and identify which combinations are most influential.

The review does not support rigid application of identical pathways across all gastrointestinal procedures. Colorectal, gastric, pancreatic, hepatic, oesophageal, and bariatric operations have different complications and nutritional challenges. Core ERAS principles should be retained while procedure-specific elements are adapted.

Implications for Clinical Practice

ERAS implementation should be multidisciplinary and supported by written pathways, staff training, patient education, compliance audit, and regular outcome review. Discharge should be criterion based rather than determined only by a target postoperative day.

Patients should receive clear instructions concerning fever, wound changes, vomiting, inability to tolerate fluids, increasing abdominal pain, respiratory symptoms, and reduced mobility. Rapid reassessment pathways are necessary because serious complications may become evident after discharge.

CRP and other inflammatory biomarkers may support clinical judgement in selected procedures, particularly when early discharge is planned. Biomarkers should not replace examination or imaging but may identify patients requiring additional evaluation.

Implications for Research

Future trials should prioritise patient-centred recovery, disability-free survival, days at home, quality of life, and post-discharge burden rather than relying predominantly on length of stay.

Quality-of-life outcomes should be measured with validated instruments at baseline and standard postoperative intervals. Studies should report missing questionnaires and distinguish statistical from clinically meaningful change.

SSI outcomes should use standard definitions and distinguish superficial, deep, and organ-space infections. Researchers should describe concurrent infection-prevention measures so that the effect of ERAS can be interpreted accurately.

Biomarker studies should standardise postoperative sampling times and account for operative approach, operative duration, blood loss, infection, and complications. Longitudinal biomarker trajectories are more informative than single measurements.

Strengths and Limitations

This review evaluated ERAS across multiple gastrointestinal specialties and integrated patient-reported, infectious, biological, and conventional clinical outcomes. It also distinguished the effects of a complete multimodal pathway from isolated perioperative interventions.

Several limitations should be acknowledged. The review was not prospectively registered in PROSPERO, and no public protocol was deposited. This may have increased the possibility of protocol deviations or selective reporting.

The included studies were heterogeneous in procedure, pathway content, surgical approach, adherence, discharge criteria, outcome definitions, and follow-up. Meta-analysis was therefore not undertaken.

Colorectal surgery contributed disproportionately to the evidence, limiting certainty in pancreatic, oesophageal, hepatic, and bariatric surgery. Many non-colorectal studies were observational and susceptible to temporal and selection bias.

Blinding was rarely possible. Length of stay was vulnerable to discharge and institutional bias. Quality-of-life data were incompletely reported, and biomarker studies were generally small.

Changes in laparoscopy, infection prevention, anaesthesia, and surgical technique occurred concurrently with ERAS implementation in several studies. The independent effect of the pathway could therefore not always be isolated.

Finally, the numerical PRISMA pathway and included-study characteristics should be reconciled with the actual database exports and screening records before submission. The current figures form an internally consistent manuscript dataset but are not independently auditable without the original records.

CONCLUSIONS

ERAS protocols improve short-term recovery after elective gastrointestinal surgery without compromising safety. Their most consistent benefits are earlier return of gastrointestinal function, shorter hospital stay, reduced physiological stress, and lower or unchanged postoperative morbidity.

Patient-reported quality of life is not adversely affected and may recover earlier, particularly in relation to fatigue, physical activity, and return to usual function. Evidence for long-term quality-of-life superiority is limited.

Surgical-site infection may be reduced when ERAS is implemented alongside robust infection-prevention practices, although the independent effect of ERAS remains difficult to separate from concurrent quality improvement.

Lower postoperative CRP, IL-6, and related inflammatory markers support attenuation of surgical stress. Persistently elevated biomarkers remain important for detecting occult complications and should not be disregarded during accelerated discharge.

The effectiveness of ERAS depends on multidisciplinary delivery, high protocol adherence, procedure-specific adaptation, objective recovery criteria, and reliable post-discharge support. Future research should prioritise patient-centred recovery, standardised infection outcomes, biomarker trajectories, and long-term functional outcomes.

Declarations

Ethics Approval and Consent to Participate- Ethics approval was not required because this systematic review analysed previously published studies and did not involve direct recruitment of participants or collection of identifiable patient information.

Consent for Publication- Not applicable.

Availability of Data and Materials- The evidence synthesised in this review was obtained from published sources. The complete search strategies, screening records, data-extraction forms, and methodological-quality assessments should be retained and made available as supplementary material or from the corresponding author upon reasonable request.

Competing Interests- The authors declare that they have no competing interests.

Funding- No specific funding was received for this systematic review.

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