Surgery · Medical Literature
The Effect of Early Mobilization as Part of Enhanced Recovery After Surgery on Postoperative Outcomes After Emergency Abdominal Surgery: A Systematic Review and Meta-Analysis.
Abstract
Early mobilization is considered a key strategy for enhancing recovery after elective surgery, yet its effect after emergency surgery remains unclear. Through this systematic review, we aim to isolate mobilization as a postoperative variable in an emergency setting to clarify its role in recovery and support evidence-based clinical guidelines. A systematic search was conducted in MEDLINE, Embase, and Cochrane on November 20, 2024, to identify studies on mobilization after emergency abdominal surgery. The review was registered in PROSPERO (CRD42024556789). Eligible studies reported short-term outcomes of postoperative mobilization, including postoperative complications, mortality, length of stay, and postoperative convalescence in adult patients. Studies were excluded if they focused exclusively on elective surgery. Studies were screened independently by two reviewers. Risk of bias was assessed using the ROB-2 for randomized controlled trials (RCTs) and ROBINS-I for observational studies. Meta-analyses used random-effects model, with results expressed as risk ratios, odds ratios or mean differences. Certainty of evidence was evaluated with GRADE. The search yielded 3064 records, of which 19 studies met inclusion criteria (seven RCTs and 12 observational studies), involving 3222 patients. Interventions mainly included early mobilization as part of ERAS protocols. Overall risk of bias was high and certainty of evidence very low. Observational studies showed reduced major complication (OR 0.75 (95% CI [0.61; 0.93])), whereas RCTs found no significant difference. Early mobilization reduced length of stay (RCTs: MD -1.95 days (95% CI [-3.16; -0.75])); Observational: MD -2.84 days (95% CI [-3.84; -1.83]) and time to first diet (RCTs: MD 0.95 days (95% CI [-1.61 to -0.29])); Observational: MD -2.30 days (95% CI [-2.36 to -2.24]). Return of bowel function was earlier (RCTs: MD -0.87 days (95% CI [-1.59; -0.16])); Observational: -0.91 days (95% CI [-1.71; -0.10]). RCTs also reported less postoperative nausea and vomiting (RR 0.46 (95% CI [0.33; 0.65])). Postoperative mobilization may reduce major complications, hospital stay and accelerate recovery, primarily as a part of an ERAS protocol. However, certainty of evidence remains very low. Most studies had a serious risk of bias, highlighting the need for high-quality RCTs.
Clinical relevance
Does early mobilization, particularly as a component of Enhanced Recovery After Surgery (ERAS) protocols, improve postoperative outcomes — including major complications, length of stay, return of bowel function, and time to first diet — compared to standard care in adult patients undergoing emergency abdominal surgery? __SNAPSHOT__ {"studyDesign":"Systematic review and meta-analysis (random-effects model); included 7 RCTs and 12 observational studies; risk of bias assessed with ROB-2 (RCTs) and ROBINS-I (observational); certainty of evidence graded using GRADE","setting":"Multi-database search (MEDLINE, Embase, Cochrane); international; registered in PROSPERO (CRD42024556789); search conducted November 20, 2024","sampleSize":"n = 3,222 patients across 19 included studies (7 RCTs, 12 observational studies) from 3,064 records screened","population":"Adult patients undergoing emergency abdominal surgery; studies exclusively involving elective surgery were excluded","intervention":"Early postoperative mobilization, primarily delivered as part of ERAS protocols","comparator":"Standard or usual postoperative care (non-ERAS / non-structured mobilization)","primaryOutcome":"Short-term postoperative outcomes: major complications, mortality, length of hospital stay, and postoperative convalescence (including return of bowel function and time to first diet)","followUp":"Short-term (exact postoperative follow-up duration not reported in abstract)","fundingSource":"Not reported"}
Key findings
Across 19 included studies (n = 3,222), results were discordant by study design. For major postoperative complications, observational studies demonstrated a statistically significant reduction favoring early mobilization (OR 0.75, 95% CI [0.61–0.93]), whereas pooled RCT data found no significant difference (exact RCT OR/RR and p-value not reported in abstract). For length of hospital stay, both study types showed significant reductions: RCTs (MD −1.95 days, 95% CI [−3.16 to −0.75]) and observational studies (MD −2.84 days, 95% CI [−3.84 to −1.83]). Time to first diet was reduced in both groups: RCTs (MD −0.95 days, 95% CI [−1.61 to −0.29]) and observational studies (MD −2.30 days, 95% CI [−2.36 to −2.24]). Return of bowel function was earlier in both: RCTs (MD −0.87 days, 95% CI [−1.59 to −0.16]) and observational studies (MD −0.91 days, 95% CI [−1.71 to −0.10]). RCTs additionally reported a significant reduction in postoperative nausea and vomiting (RR 0.46, 95% CI [0.33–0.65]). Overall risk of bias was rated as high and GRADE certainty of evidence as very low. Mortality outcomes were not separately reported in the abstract. NNT was not calculable from available data.
Practice implications
This systematic review and meta-analysis suggests that early mobilization — predominantly when embedded within ERAS protocols — is associated with shorter hospital stays, faster return of bowel function, earlier tolerance of diet, and reduced postoperative nausea and vomiting after emergency abdominal surgery. The association with reduced major complications was detected only in observational studies and not confirmed in the higher-quality RCT subgroup, which is a critically important distinction. The overall risk of bias was high and GRADE certainty was rated very low, meaning results must be interpreted with substantial caution. The findings cannot be attributed to mobilization alone, as the intervention was typically bundled within multi-element ERAS protocols, making it impossible from the available data to isolate the independent effect of mobilization. Patients who were unable to mobilize independently — likely representing those with greater physiological derangement, frailty, or operative severity — may have been systematically under-represented in the included studies, limiting generalizability to the highest-acuity emergency surgical patients. Current evidence does not support a change in practice based on this review alone; however, it reinforces the biological plausibility of mobilization as a beneficial perioperative strategy and underscores the urgent need for well-designed, adequately powered RCTs that isolate mobilization as a single variable. Only the abstract was available for this summary, which limits full critical appraisal of individual study characteristics, heterogeneity statistics (I²), and subgroup analyses. __LIMITATIONS__ Overall risk of bias rated as HIGH across included studies; most studies assessed as having serious risk of bias.,GRADE certainty of evidence rated as VERY LOW for all outcomes, substantially limiting confidence in effect estimates.,Early mobilization was delivered predominantly as part of bundled ERAS protocols, precluding isolation of mobilization as the independent active ingredient.,Critical discordance between RCT and observational data for major complications undermines confidence in the observed benefit; observational studies are highly susceptible to confounding by indication.,Significant clinical and methodological heterogeneity is expected across 19 studies spanning varied emergency abdominal procedures, patient populations, and mobilization definitions; heterogeneity statistics (I²) not reported in abstract.,Definition of 'early mobilization' was likely inconsistent across studies, reducing the precision of pooled estimates.,Patients with the highest acuity, frailty, or physiological instability — who stand to benefit or be harmed most — were likely under-represented.,Short-term follow-up only; long-term functional recovery, quality of life, and 30- or 90-day mortality not reported.,Funding sources not reported; potential for publication bias in favor of positive ERAS outcomes cannot be excluded.,Only the abstract was available for this summary; full-text appraisal of individual study details, sensitivity analyses, and funnel plots was not possible. __BOTTOM_LINE_CATEGORY__ low_certainty __BOTTOM_LINE__ Early mobilization within ERAS protocols after emergency abdominal surgery is associated with modestly shorter hospital stays, faster return of bowel function, and reduced postoperative nausea and vomiting, but these findings are based on very low certainty evidence with a high overall risk of bias. Crucially, the only RCT-level data available did not confirm a significant reduction in major complications, which was seen only in observational studies susceptible to confounding. This review should not change current practice but strongly reinforces the need for high-quality, adequately powered RCTs that isolate mobilization as a discrete intervention in the emergency surgical setting.