Tolerance to and postoperative outcomes with early oral feeding following elective bowel surgery: a systematic review

Article information

Ann Coloproctol. 2024;.ac.2023.00472.0067

Publication date (electronic) : 2024 March 13

doi : https://doi.org/10.3393/ac.2023.00472.0067

Department of Surgery, NYC Health + Hospitals/Lincoln, New York City, NY, USA

Correspondence to: Lord Mvoula, MD Department of Surgery, NYC Health + Hospitals/Lincoln, 234 East 149th St, Bronx, New York City, NY 10451, USA Email: lord.mvoula@gmail.com

Received 2023 July 17; Revised 2023 September 29; Accepted 2023 November 21.

Abstract

Purpose

Advancements in gastrointestinal surgery have directed attention toward optimizing recovery, including through the use of feeding methods that reduce prolonged postoperative hospital stays, complications, and mortality, among other undesirable outcomes. This study’s primary goals were to identify current peer-reviewed literature reporting the postoperative outcomes of elective bowel surgery and to evaluate the clinical evidence of patients’ tolerance to oral feeding following elective bowel surgery.

Methods

An exhaustive literature search was conducted via PubMed and Scopus. The search results were screened for potential articles, and articles were assessed for eligibility based on prespecified eligibility criteria. The data were synthesized, and the results were reported and discussed thematically.

Results

The database search yielded 1,667 articles, from which 18 randomized controlled trials were chosen for inclusion in this study. This study included 874 early oral feeding (EOF) patients, 865 traditional oral feeding patients, and 91 patients whose postoperative care was unspecified. Data synthesis was done, and meta-analyses were conducted. The results showed that EOF patients required a significantly shorter time to tolerate a solid diet and had shorter hospital stays. In addition, bowel function was restored earlier in EOF groups.

Conclusion

The results show good tolerance to EOF, shorter hospitalizations, and faster restoration of bowel function, suggesting that EOF after elective bowel surgery is relatively safe. However, further studies with similar baseline conditions should be conducted to verify these results.

Keywords: Intestines; Midline incision; Colorectal surgery; Diet enteral feeding

INTRODUCTION

Bowel complications are a common occurrence after surgical interventions, such as gastrointestinal (GI) surgery. Advancements in GI surgery have directed attention toward optimizing recovery [1]. Traditional postoperative care for GI surgery involves withholding oral diet intake until the resolution of ileus, which is typically characterized by the passage of flatus or stool [1]. In a break from traditional oral feeding (TOF) practice, the American Society for Enhanced Recovery (ASER), Perioperative Quality Initiative (POQI), and the European Society for Clinical Nutrition and Metabolism (ESPEN) recommended resumption of oral feeding, including clear liquids, oral nutritional support, and a balanced diet following GI surgery to facilitate postsurgery recovery, shorten the length of hospitalization, and reduce postoperative morbidity and mortality [2]. In addition, the resumption of oral nutrition immediately after GI surgery is also included as a care element in the Enhanced Recovery After Surgery (ERAS) protocol [3].

Despite the growing scientific consensus and patient preference for early oral feeding (EOF) after GI surgery, it is common practice to resume oral intake of fluids or solid meals only after the return of bowel function [4–6]. It has been reported that only a third of patients may tolerate solid meals by the 2nd postoperative day (POD), and half of the patients by POD 4 [7]. However, the results are inconclusive regarding the safety and efficacy of EOF. Therefore, there is a disconnect between practice guidelines and the standard practice of traditional care after elective GI surgery.

EOF involves the administration of an oral diet on the 1st postoperative day. Signs of intolerance to EOF include loss of appetite, nausea, and vomiting [8], and are discussed in this paper. Other postoperative outcomes, including complications, the length of hospitalization, restoration of bowel function, and adverse events like death, are also discussed in this study. Therefore, the primary aim of this study was to appraise the evidence of the tolerance of EOF, and the effects associated with it among patients who have undergone bowel surgery.

METHODS

The reporting of this study adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) [9].

Identification and selection of studies

Search strategy

A comprehensive search was done to identify peer-reviewed scholarly articles that reported on tolerance to EOF and other postoperative outcomes following elective bowel surgery. The PubMed and Scopus databases were searched using the following search terms in different combinations: postoperative, rectum, anus, colon, intestine, bowel, surgery, colostomy, resection, abdominoperineal, clear fluid, oral feed, feeding, solid feeding, eat, and eating. A manual search was conducted on other references sourced from previous reviews and meta-analyses.

Eligibility criteria

This study included research articles on tolerance to EOF and other postoperative outcomes following elective bowel surgery. Articles were included with the following criteria: studies with online access to the full text; randomized controlled trials that specified the type of postoperative feeding for patients; studies reported in the English language or that could be translated into the English language; studies on adult patients; and studies whose participants underwent bowel surgery to manage underlying bowel conditions following diagnosis. The following articles were excluded: reviews, meta-analyses, opinion pieces, letters, and study protocols; studies on patients who underwent emergency bowel surgery, palliative bowel surgery, or patients who required prolonged postoperative enteral nutrition; studies without methods or results; studies with only abstracts; and cohort studies and case series.

Data selection and extraction

A reviewer made the study selection. Articles were screened by title and abstract, after which retrieval and full-text screening were conducted. The original inclusion and exclusion criteria were adjusted during the screening to enhance the results' interpretability and the outcomes' clinical significance. Studies on patients who underwent emergency bowel surgery, palliative bowel surgery, or patients who required prolonged postoperative enteral nutrition were excluded. Additionally, only randomized controlled trials were included to elevate the study to level 1 of evidence. Cohort studies and case series were excluded. Data from the included studies were systematically extracted and double-checked for consistency (as presented in Table 1 [10–27]) and included the following: author, study design, EOF sample size, mean age of EOF patients, TOF sample size, mean age of TOF patients, the surgical technique employed, the purpose of the study, outcome measure, and findings.

Table 1.

Description of the included studies

Methodological quality assessment

To assess the methodological quality of the randomized controlled trials included in this study, the Cochrane Risk of Bias tool (Cochrane Collaboration) was used [28]. A traffic light plot is presented in Fig. 1 [10–27], and a summary plot is in Fig. 2.

Fig. 1.

Traffic lights plot for risk of bias assessment of the included studies.

Fig. 2.

Summary plot of the risk of bias assessment of the randomized controlled trials.

Statistical analysis

Study characteristics are presented in Table 1 [10–27]. The outcomes were thematically analyzed into tolerance to oral diet, hospitalization length, bowel function restoration, adverse outcomes, and postoperative complications. MetaXL was used to calculate the prevalence/percent occurrence of complication events. The use of the standardized mean difference (SMD) in this type of meta-analysis was considered the best option. Meta-analysis was carried out in Cochrane Review Manager (RevMan ver. 5.4.1, Cochrane Collaboration) using inverse-variance (mean and standard deviation values), a random-effects model and a 95% confidence interval (CI). Heterogeneity between studies was tested using the I² statistic. A P-value of 0.05 was adopted as the significance threshold.

RESULTS

Study selection

The literature search yielded 1,667 articles, from which 71 duplicates were removed. Further, 809 articles were removed before the screening, and 537 were excluded following title and abstract screening. The remaining 321 articles were sought for retrieval, after which 18 randomized controlled trials that met the eligibility criteria were included. The results are presented in Fig. 3.

Fig. 3.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) flowchart showing results of the study selection process.

Risk of bias in the included studies

In the risk of bias assessment of the 18 included studies [10–27], we found that all of them exhibited a low risk of bias in various key domains, including randomization, deviations from intended intervention, missing outcome data, and outcome measurement. Specifically, none of the studies showed significant bias in these domains. However, in the domain of bias in the selection of reported results, only 2 studies [11, 12] raised “some concerns.” Therefore, the overall risk of bias for the 18 studies was predominantly low, with 16 studies [10, 13–27] demonstrating low risk and only 2 studies [11, 12] having some concerns in the selection of reported results (Figs. 1, 2).

Thematic analysis of the included studies

The study characteristics are presented in Table 1 [10–27]. In this section, significant themes are reviewed, including tolerance to the patient’s oral diet, hospitalization length, bowel function restoration, adverse outcomes, and postoperative complications [29].

Tolerance to oral diet

A significantly shorter time was required to start a solid diet among EOF patients than among TOF patients, with an SMD of –1.35 (95% CI, –1.88 to –0.81; P<0.00001), as shown in Fig. 4 [14, 23].

Fig. 4.

Forest plot comparing early oral feeding (EOF) and traditional oral feeding (TOF) regarding time to tolerate a solid diet. SD, standard deviation; IV, inverse-variance; Random, random-effects model; CI, confidence interval.

Length of hospitalization

Hospital stays, defined in terms of the number of days spent in the hospital postoperatively, were significantly shorter in the EOF group than in the TOF group. EOF patients also spent substantially fewer postoperative days in the hospital, as shown in Fig. 5 [13–15, 17, 19, 23–25, 27].

Fig. 5.

Forest plots comparing the length of hospitalization between early oral feeding (EOF) and traditional oral feeding (TOF) groups among patients who underwent (A) bowel surgery and (B) colorectal surgery. SD, standard deviation; IV, inverse-variance; Random, random-effects model; CI, confidence interval.

The SMD of the number of days in the hospital for bowel surgery patients was –0.92 (95% Cl, –1.56 to –0.27; P<0.00001). High heterogeneity was observed (I²=91%) (Fig. 5A) [13, 19, 23, 25, 27].

The SMD of the number of days in the hospital for colorectal surgery patients was –1.46 (95% Cl, –2.57 to –0.34; P<0.00001). High heterogeneity was observed (I²=97%) (Fig. 5B) [14, 15, 17, 24].

Adverse outcomes and postoperative complications

Adverse outcomes and reported complications included anastomotic leaks, fever, and death. Anastomotic leak and, ultimately, death were reported in a patient in the TOF group [17, 19]. In addition, da Fonseca et al. [13] and Stewart et al. [26] reported 1 death among EOF and TOF patients, respectively. Nematihonar et al. [20] reported that 19.5% of EOF patients had complications, compared to 22.2% of TOF patients. Statistically insignificant differences between the EOF and TOF groups were reported regarding postoperative complications [10, 12, 14, 16, 18, 19, 25, 26]. Abdominal distention, wound infection, elevated body temperatures, anastomotic leak, deaths, and other adverse postoperative outcomes were similar between both groups [23].

Conversely, in a study by Zhou et al. [27], the total occurrence of complications was significantly higher in the EOF group (P<0.001). However, fever, infections, and pharyngolaryngitis were more prevalent in the TOF group. Additionally, anastomotic leak, swelling of the stomach, and wound complications arose with similar frequency among the groups in the study.

Mortality rate

The pooled mortality rate among those who received surgery was 2.66% (95% CI, 1.05% to 4.92%), with a Cochran Q value of 1.185 and a P-value of 0.88 (Fig. 6) [13, 17, 19, 23, 26].

Fig. 6.

Mortality rates. CI, confidence interval.

Anastomotic leak

The pooled prevalence for the occurrence of anastomotic leak was 3.34% (95% CI, 1.96% to 5.07%). The Cochran Q value was 9.22 and the P-value was 0.25 (Fig. 7) [13, 14, 17, 19, 23, 25–27].

Fig. 7.

Rates of anastomotic leak. CI, confidence interval.

Restoration of bowel function

Bowel function was evaluated using different parameters, such as bowel movement, the passage of flatus, and stool. The EOF group showed a significantly shorter time to the passage of the first flatus (SMD, –1.01; 95% CI, –1.52 to –0.50; P=0.0001), with a heterogeneity of 90%, as shown in Fig. 8 [13, 15, 20, 23, 25, 27].

Fig. 8.

Forest plot comparing the early oral feeding (EOF) and traditional oral feeding (TOF) groups regarding the time to the first passage of flatus. SD, standard deviation; IV, inverse-variance; Random, random-effects model; CI, confidence interval.

The EOF group showed a significantly shorter time to the passage of the first flatus, as shown in Fig. 9 [14, 15, 20, 23, 25, 27]. The SMD for the time to stool passage after bowel surgery was –1.01 (95% CI, –1.51 to –0.52; P<0.0001), with a heterogeneity of 86% (Fig. 9A) [20, 23, 25, 27]. The SMD for the time to stool passage after colorectal surgery was –0.84 (95% CI, –1.15 to –0.53; P<0.00001), with a heterogeneity of 42% (Fig. 9B) [14, 15].

Fig. 9.

Forest plot comparing stool passage time between early oral feeding (EOF) and traditional oral feeding (TOF) groups among patients who underwent (A) bowel surgery and (B) colorectal surgery. SD, standard deviation; IV, inverse-variance; Random, random-effects model; CI, confidence interval.

DISCUSSION

EOF has been considered an essential approach to enhancing and optimizing recovery and thereby restoring the quality of life among patients following elective bowel [8]. Tolerance to EOF was reported by 12 of the studies examined in this study. Tolerance was evaluated by the frequency of nausea, vomiting, and appetite loss [30]. Dietary intake was significantly different between the EOF and TOF groups. The oral diet was administered in various ways, ranging from nil by mouth, clear liquids, all liquids, and a soft diet, to a solid diet. Clear liquids were administered to the TOF group, whereas a solid diet was administered to the EOF group on the 1st postoperative day in this study.

The results suggest an excellent tolerance to EOF among EOF patients, with comparable outcomes to those of TOF patients regarding vomiting and nausea. Dag et al. [14] reported that 85.9% of EOF patients tolerated the postoperative care schedule. Hartsell et al. [17] reported a 55% tolerance to the feeding schedule among EOF patients versus a 50% tolerance among TOF patients. Patients who did not tolerate EOF were reported to experience repeated vomiting and abdominal swelling [15].

A total of 48% of EOF patients reported vomiting, compared to 33% in the TOF group. Minig et al. [19] reported that 78% of EOF patients resumed solid oral intake on the 1st postoperative day. Instances of vomiting and nausea were comparable and did not show a statistically significant significance between the EOF and TOF patients [13, 20, 24]. The different postoperative care groups exhibit similar tolerance to early oral diets [22]

The surgical interventions used to manage bowel complications are associated with postoperative complications, like other standard surgical procedures [31]. Comparable adverse outcomes and postoperative complication rates were found in EOF and TOF patients. Common complications included anastomotic leaks, morbidity, fever, and death. Complications directly impact other outcomes, such as the length of hospitalization and hospital readmission, among others [32]. However, the results were inconsistent, given the differences in the studies’ baseline conditions, including study design.

Prolonged hospital stays are often undesirable and associated with complications, such as muscle weakness and thromboembolic events [33]. In this study, the length of hospitalization was evaluated in terms of the number of days after surgery until discharge. Hospitalization was significantly shorter among EOF patients in most of the included studies. However, some studies reported similar postoperative lengths of stay in the hospital. As reported in this paper, variations might have arisen from the different study designs.

The quality of a patient’s recovery following elective bowel surgery is often assessed by the restoration of bowel function. This metric is evaluated by the early return of bowel function, including the passage of flatus and stool, in addition to bowel movements [20]. Most of the included studies reported that bowel function was restored in a shorter time (in terms of the time to the passage of the first flatus and stool) among EOF patients than among TOF patients. However, similar results were obtained regarding when the first bowel movement was noted.

In conclusion, the results of this study—good tolerance to EOF, shorter hospital stays, and faster restoration of bowel function—suggest that EOF after elective bowel surgery is relatively safe. However, some of the included studies reported inconsistent results due to differences in the study setting and study design. Therefore, further studies should be conducted with identical baseline conditions to verify the results of this study.

Notes

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Funding

None.

Author contributions

Conceptualization: all authors; Investigation: all authors; Methodology: all authors; Validation: all authors; Writing–original draft: all authors; Writing–review & editing: all authors. All authors read and approved the final manuscript.

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Table 1.

Description of the included studies

Study	Study design	EOF		TOF		Surgical technique	Study purpose	Outcome measure	Finding
Study	Study design	Sample size	Mean age (yr)	Sample size	Mean age (yr)	Surgical technique	Study purpose	Outcome measure	Finding
Behrns et al. [10] (2000)	RCT	27	45±3^a	17	47±4^a	Elective intestinal surgery	To determine the safety and length of hospital stay due to early initiation and discharge on a clear liquid diet	Postoperative intestinal-related sequelae, complications, and readmission rate	Early initiation and discharge on a clear liquid diet following elective intestinal surgery decreased the length of hospital stay and were safe
Binderow et al. [11] (1994)	Prospective randomized study	32	52	32	52	Colon or small bowel resection	To evaluate whether early postoperative feeding is possible after laparotomy and colorectal resection	Rate of nasogastric tube reinsertion, duration of postoperative ileus, and length of hospitalization	Early oral intake was possible after laparotomy and colorectal resection
Lobato Dias Consoli et al. [12] (2010)	RCT	15	54.5	14	47.4	Colorectal resection	To evaluate the impact of early postoperative oral feeding in patients undergoing elective colorectal resection	Hospital stay, complication rates, and acceptance of diet	Early oral intake was well tolerated, led to significantly shorter hospital stays, and did not increase complications
da Fonseca et al. [13] (2011)	Prospective randomized study	24	57.4±16.3^a	26	51.7±13.3^a	Elective colonic surgery	To assess the safety and the benefit of a simplified, well-defined perioperative rehabilitation program for elective colonic surgery, mainly focused on early oral nutrition	Diet tolerance	Early oral nutrition associated with a simplified perioperative rehabilitation program reduced the postoperative length of hospital stay and ileus time after elective colonic resection, without increasing rates of complications or readmissions
Dag et al. [14] (2011)	Prospective randomized clinical study	99	62	100	61	Colorectal surgery	To evaluate the safety and tolerability of EOF after colorectal operations	Bowel movements, defecation, and time of tolerance of solid diet	Early postoperative feeding was safe and led to the early recovery of gastrointestinal functions
El Nakeeb et al. [15] (2009)	RCT	60	52.3±12.5^a	60	56.3±11.6^a	Colonic anastomosis	To assess the safety outcome of EOF and reports on the factors affecting early postoperative feeding after colorectal procedures	Time to first passage of flatus and stool, hospital stay	EOF after colorectal surgery was safe and tolerated by most patients
Feo et al. [16] (2004)	RCT	50	67.6±10.4^a	50	67.6±10.2^a	Colorectal resection	The effect of EOF without nasogastric decompression following elective colorectal resection for cancer	Resumption of intestinal function and length of hospital stay	Patients undergoing elective colorectal resection could be managed without postoperative nasogastric catheters, starting oral feeding on the 1st postoperative day
Hartsell et al. [17] (1997)	RCT	29	66	29	68	Colorectal surgery	To investigate whether successful early feeding would lead to a shorter duration of hospitalization and, therefore, would be more cost-effective	Rates of nausea and length of hospital stay	EOF after elective colorectal surgery was safe
Lucha et al. [18] (2005)	RCT	51	51	51	51	Colorectal resection	To investigate hospitalization, hospital costs, morbidity, and time to diet tolerance	Length of hospital stay, hospital costs, morbidity, and time to tolerance of a diet	Early postoperative enteral support did not reduce hospital stay, nursing workload, or costs
Minig et al. [19] (2009)	RCT	18	54	22	58	Intestinal resection	To assess the outcomes of EOF and TOF in gynecologic oncology patients undergoing laparotomy with associated intestinal resection	Hospital stay	Early resumption of oral intake was feasible and safe in gynecologic oncology
Nematihonar et al. [20] (2019)	RCT	54	64.1±13.9^a	54	50.58±18.2^a	Small intestine anastomosis	To compare the outcome of EOF versus EOF in patients undergoing elective small intestine anastomosis	-	EOF shortened the time of the first passage of stool and reduced the length of hospital stay
Ortiz et al. [21] (1996)	RCT	95	65.54	95	65.70	Elective colon or rectal operation	To assess the feasibility and safety of immediate oral feeding in patients subjected to elective open colorectal surgery	Tolerance to oral intake, bowel movement	EOF was feasible and safe for patients with elective colorectal surgery
Ortiz et al. [22] (1996)	Prospective randomized study	20^b	52	20^c	56	Colorectal surgery	To assess whether the time before oral food intake after laparoscopy-assisted surgery is shorter than that after standard laparotomy	Ability to tolerate the early oral intake of food, the frequency of vomiting, or the incidence of insertion of a nasogastric tube	This study invalidated the claim by laparoscopic surgeons that their patients tolerate earlier oral intake of food than patients who undergo standard procedures
Pragatheeswarane et al. [23] (2014)	Prospective RCT	60	46.5±17.2^a	60	46.9±16.5^a	Elective open bowel surgery	To compare the safety, tolerability, and outcome of EOF versus traditional feeding in patients undergoing elective open bowel surgery	Time to first flatus and defecation, time to start solid eating	Early postoperative feeding was safe, was well tolerated, and reduced the length of hospitalization
Reissman et al. [24] (1995)	RCT	80	51	81	56	Colon or small bowel resection	To prospectively assess the safety and tolerability of EOF after elective "open" abdominal colorectal operations	Length of hospitalization, nasogastric tube reinsertion, and rate of vomiting	EOF after elective colorectal surgery was safe and could be tolerated by most patients
Nematihonar et al. [25] (2018)	RCT	30	45.8±17.1^a	30	46.8±13.6^a	Colorectal anastomosis	To determine the safety and feasibility of an unconventional postoperative oral intake protocol in patients with colorectal anastomosis	Times to the first passage of flatus and stool	EOF after colorectal surgery was safe and tolerated by most patients
Stewart et al. [26] (1998)	Prospective randomized trial	40	58	40	59	Colorectal surgery	To compare early feeding to traditional management in open elective colorectal resection patients	Time to tolerate a diet	Early feeding was successfully tolerated leading to earlier resolution of ileus and less hospitalization
Zhou et al. [27] (2006)	RCT	161	55.3±16.7^a	155	57.1±19.8^a	Colorectostomy	To evaluate the feasibility, safety, and tolerance of early removing gastrointestinal decompression and EOF in colorectal carcinoma patients	Time to the passage of stool, length of postoperative stay, and acute dilation of the stomach	Application of gastrointestinal decompression after colorectostomy could not effectively reduce postoperative complications

EOF, early oral feeding; TOF, traditional oral feeding; RCT, randomized controlled trial.

Mean±standard deviation.

Laparoscopy-assisted.

Laparoscopy.