Lim Siew Hoon
PhD (Nursing) student, BSc (Nursing) (Honours), RN
Singapore National University Hospital Centre for Evidence Based Nursing: A collaborating centre of the Joanna Briggs Institute, Singapore; Singapore General Hospital
Contact number: +65 9180 2031
Mohamad Sharan Bin Mohamad Osman
Singapore National University Hospital Centre for Evidence Based Nursing: A collaborating centre of the Joanna Briggs Institute, Singapore; Singapore General Hospital
Contact number: +65 97616730
The objective of this systematic review is to synthesise the best available quantitative research evidence on the early enteral feeding in adult patients (18 + years old) after colorectal surgery in the hospital setting.
The specific review questions to be addressed are:
- What is the effect of early enteral feeding on the wound infections and intra-abdominal abscesses?
- What is the effect of early enteral feeding on the post-operative complications?
- What is the effect of early enteral feeding on the anastomotic leakages?
- What is the effect of early enteral feeding on the mortality within 30 days after colorectal surgery?
- What is the effect of early enteral feeding on the length of hospital stay?
- What are the significant adverse effects of early enteral feeding?
- What are the factors influencing early enteral feeding after colorectal surgery?
Nil by mouth is part of the traditional nutritional management of patients after undergoing major gastrointestinal surgery, especially colorectal. The most commonly performed operations include left and right hemicolectomy, low anterior resection, sigmoid resection, abdominoperineal resection, and miscellaneous other colon resections. Patients will then be encouraged later to take a clear liquid diet, subsequently progressing gradually to a regular food diet on the 4th to 5th day post-operatively.1, 2 The resolution of post-operative ileus has been commonly defined by the passage of flatus and stools, which represented the clinical evidence for physicians to start the patients on oral diet.3 This norm has been adhered strictly in the hospital setting since more than 100 years ago.4 The rationale for this traditional practice of food restriction after gastrointestinal surgery was the fear of increased risk of anastomotic dehiscence, aspiration pneumonia, abdominal distention, intestinal obstruction with the early exposure of the gastrointestinal tract to nutrition.5-8 Fasting the patients post-operatively also aims to prevent nausea and vomiting in patients. However, it is uncertain whether the delay of post-operative enteral feeding is actually beneficial to patients.
Early feeding entails the allowance of oral fluids by the first post-operative day, followed by the introduction of solid diet on the following day.1, 7, 9, 10 Randomised controlled trials, quasi-experimental studies and observational studies (cohort studies and case control studies) have been carried out to demonstrate the benefits of early enteral feeding in patients undergone colorectal surgery. There was a significant reduction on the wound infections, medical costs as well as the length of hospital stay.10-13 Several randomised studies have also concluded that enteral nutrition is able to reduce the development of complications including muscle deficits and post-operative fatigue.5, 6, 14 There were no reported advantages in fasting patients after undergoing gastrointestinal surgery, as well as no significant difference in anastomotic dehiscence, aspiration pneumonia, intra-abdominal abscess and mortality rate when comparing with the alternative practice of early oral feeding.11, 12 Early nutrition after gastrointestinal surgery has been shown to be well tolerated by more than 70% of the patients15, 16 It has been demonstrated that there is an improvement in the energy and protein intake with early post-operative nutrition, reduce the negative impact of the patients' metabolic response to surgery.17, 18 Reduced muscle deficits and post-operative fatigue are also demonstrated in patients with the promotion of early oral nutrition.
This alternative practice of early post-operative nutrition has been mainly carried out in the Western countries in the recent years, including United states, Australia, Netherland and Denmark.7, 19-23 The traditional practices are resistant to changes especially in the Asian countries. Recently, several quasi-experimental, controlled clinical trial studies10, 13 in Japan have been exploring the benefits of early enteral feeding, in order to improve their conservative feeding protocols.10, 13 The results have shown that utilising an alternative post-operative oral nutrition intake protocol for patients in Japan, targeted to reduce the length of post-operative hospital stay to the same as that in Western countries, was equally safe and feasible.10 It is essential for health care professionals to be aware of the feasibility and safety of an alternative post-operative oral intake protocol for patients undergoing colorectal surgery, in order to improve the effectiveness of post-operative management and adjust practices accordingly. With the improvement in current post-operative practices, there could be a reduction of post-operative medical costs, while improving patients' quality of life.
With studies to support early enteral feeding postoperatively, there have been other randomised control trials5, 16, 24 providing mixed results as well, which do not concur with the benefits of the early post-operative feeding protocol. These studies showed results of patients who were intolerant of early post-operative feeding and this protocol was discouraged to be used in a routine fashion after major colorectal surgeries. Therefore, the benefit for early enteral nutrition following colorectal surgery was not clearly established and it remained controversial if commencing enteral nutrition early was an advantage or disadvantage to the colorectal patients.
Adequate nutrition is one of the major goals of post-operative care. Evidence from the systematic review aims to update health care professionals' knowledge of the current situation of early post-operative nutrition in patients after the colorectal surgery and promotes the improvement of evidence-based practice in the surgical units. This also comprises of an important aspect of nursing care. It is critical for nurses to assess patients appropriately in the commencement of oral intake post-operatively, progressing from fluid to solids. There is a need for nurses to advocate for patients in receiving the best care based on current evidence. A thorough and systematic review of the literature is necessary to analyse the past findings about the practice of early enteral feeding in patients after colorectal surgery, recommendations that guide clinical practice, and identify gaps of knowledge for further research in this area.
Prior to commencement of this systematic review, the Joanna Briggs Institute (JBI) Library of Systematic Reviews, and Medline were searched and there were no previous systematic reviews on this specific topic found or identified as being underway. However, there was a review12 found in the Cochrane Library of Systematic Reviews on this similar topic, conducted in 2006 which focused solely on randomised controlled trials. This systematic review will aim to conduct a review up to 2011 to include all relevant types of quantitative studies with additional review objective to investigate factors influencing early enteral feeding after colorectal surgery.
Definitions for this review:
Early enteral feeding is defined as nutrition provided (tube, sip or oral) to adult patients undergone gastrointestinal surgery, mainly colorectal, within the first 24 hours post-operatively.
Wound infections refers to the interference of normal wound healing caused by the colonisation of bacteria at the wound site, presented as redness, purulent and foul discharges from wound.
Intra-abdominal abscesses are bacteria infection in the abdomen derived from surgical incision of the bowel.
Post-operative complications refer to the occurrence of acute myocardial infarction, post-operative thrombosis or pneumonia.
Anastomotic leakages are defined as the post-operative occurrence of fluid from within the gastrointestinal tract leaking into the sterile abdominal cavity.
Anastomotic dehiscence refers to the breakdown of surgical sutures in the wound.
Mortality within 30 days after colorectal surgery is defined as events of death of patients occurring within 30 days post-operatively, dependent on the age and risk factors.
Length of hospital stay refers to the number of days patients stay in the hospital after undergoing gastrointestinal surgery. Colorectal surgeries usually require a post-operative stay of five to ten days in the hospital.25
Significant adverse effects of early enteral feeding are defined as occurrence of nausea, vomiting, abdominal distension, aspiration and any other adverse effects.
Types of participants
The review will consider studies that include male and female adult patients who are 18 years old and above, of all ethnic groups with malignant and benign colorectal diseases, who have undergone colorectal surgery, receiving early enteral feeding. Patients younger than 18 years old receiving any types of surgery and patients on parenteral nutrition will be excluded from the review.
Types of interventions
The review will consider studies that include the intervention of early enteral feeding, regardless of method of enteral feeding (tube, sip or oral), defined as nutrition provided to patients undergone gastrointestinal surgery, within the first 24hours post-operatively. The comparator group will receive regular care, with feeding commencing only after their post-operative ileus resolved.
The review will consider studies that include contexts such as the acute adult? surgical care hospital settings in all countries. Studies with paediatric acute hospital settings will be excluded from the review.
Types of Outcomes
The outcomes of interest include but are not restricted to the following:
- wound infections rates
- intra-abdominal abscesses rates
- post-operative complications with the number of occurrence of events such as acute myocardial infarction, post-operative thrombosis or pneumonia
- anastomotic dehiscence rates
- mortality within 30 days after colorectal surgery
- length of hospital stay in terms of days
- Significant adverse effects of early enteral feeding including occurrence of nausea, vomiting, abdominal distention and any other adverse events
- Factors influencing early oral feeding after colorectal surgery.
Types of studies
The review will consider any randomized controlled trials, quasi-experimental studies and before and after studies for inclusion to enable the identificiation of current best evidence regarding early enteral nutrition practices in the hospital setting.
Specific Exclusion Criteria
- Studies with patients who served as their own controls
- Studies comparing different types of enteral nutrition with each other.
The search strategy aims to find both published and unpublished studies from 1990 to 2011 and in English language only.
A three-step search strategy will be utilised in this review. An initial limited search will be undertaken in MEDLINE and CINAHL databases. An analysis of the text words contained in the title or abstracts to identify the keywords and index terms used to describe relevant terms. A second extensive search using all identified keywords and index terms will then be carried out and will extend to other relevant databases. Thirdly, the reference lists and bibliographies of all identified reports and articles will be searched for additional and relevant studies.
The databases to be searched include: CINAHL; Medline; Scopus; PsycINFO; Mednar; Proquest. Due to translational limitations, only articles published in the English language will be considered for inclusion in the review.
Key search terms are identified in Appendix I.
Assessment of the methodological quality
Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using the standardized critical appraisal instruments for randomised and pseudo-randomised studies (Appendix II), cohort/case control studies (Appendix III) and descriptive/case series studies (Appendix IV) from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instruments (JBI-MASTARI).
Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer.
Quantitative data will be extracted by the two independent reviewers using the standardized JBI data extraction tools from JBI-MASTARI for randomised and pseudo-randomised studies (Appendix V), cohort/case control studies (Appendix VI) and descriptive/case series studies (Appendix VII). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives, for the quantitative studies.
Where possible quantitative research study results will be combined in statistical meta-analysis using the JBI-MAStARI. All results will be double entered. Odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed using the standard Chi-square. Where statistical pooling is not possible, the findings will be presented in narrative form.
Conflicts of Interest
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12. Andersen HK, Lewis SJ, Thomas S. Early enteral nutrition within 24h of colorectal surgery versus later commencement of feeding for postoperative complications. Cochrane Database of Systematic Reviews. 2006(4).
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Appendix I Key Search Terms
Appendix II JBI Critical Appraisal Checklist for Randomised and Pseudorandomised Studies
Appendix III JBI Critical Appraisal Checklist for Cohort/Case Control Studies
Appendix IV JBI Critical Appraisal Checklist for Descriptive/ Case Series
Appendix V JBI MAStARI Data Extraction Tool for Randomised and Pseudo-Randomised Studies
JBI Data Extraction Form for Experimental/Observational Studies
Appendix VI JBI MAStARI Data Extraction Tool for Cohort/Case Control Studies
Appendix VI JBI MAStARI Data Extraction Tool for Descriptive/Case Series Studies