Background: This study sought to conduct a systematic review providing a comparative analysis of enteral nutrition (EN) and parenteral nutrition (PN) after hepatectomy.
Methods: PubMed, Embase, and the China National Knowledge Infrastructure databases were searched for publications describing randomized controlled trials that compared early EN and PN after hepatectomy. The time period for this search was from January 1990 to December 2013. In accordance with the inclusion criteria of this study, two researchers independently screened the retrieved literature, extracted data, and assessed methodological quality. A meta-analysis of the included publications was then performed using RevMan 5.2 software.
Results: The meta-analysis results indicated statistically significant differences between the group that received EN and the group that received PN during the early stages after hepatectomy with respect to average total bilirubin and alanine aminotransferase levels after nutrition, prealbumin levels, incidence of diarrhea and abdominal bloating, time to flatus, and average cost of nutrition. To varying degrees, better results were observed in the EN group than in the PN group for these metrics.
Conclusion: During the early stages after hepatectomy, EN has obvious advantages relative to PN; thus, EN merits more widespread promotion and application in this clinical context.
Keywords: hepatectomy, enteral nutrition, parenteral nutrition, systematic review, meta-analysis
Hepatectomy is an important treatment method for benign and malignant liver disease.1 The pathophysiological changes that occur after hepatectomy are complex; in particular, one issue that patients face is that the residual liver must not only recover but also compensate for the functions of the removed portion of liver. Postoperative nutritional support helps to promote early recovery by patients who have undergone hepatectomy.2,3 Numerous studies have demonstrated that parenteral nutrition (PN) can easily deviate from physiological nutritional processes;4–6 these deviations may damage liver function, resulting in liver enzyme abnormalities, cholestasis, or even liver failure, among other complications.7 Relative to PN, enteral nutrition (EN) is considered to be more similar to physiological nutrition; thus, the use of EN instead of PN can avoid the disuse of intestinal function, prevent the translocation of intestinal flora, promote the recovery of intestinal barrier function, and promote the secretion of digestive and gastrointestinal hormones.8,9 However, some researchers still recommend conventional treatment typically consisting of PN therapy with a gradually supplemented diet after anal aerofluxus. Further, there is no evidence that PN or EN is better than no therapy. To address whether EN or PN is the preferred nutritional support approach during the early stages after hepatectomy, we performed a systematic review and meta-analysis of studies comparing early EN and PN after hepatectomy.
MATERIALS AND METHODS
We used the PubMed and Embase databases to search for relevant English language literature and the Wanfang and China National Knowledge Infrastructure databases to search for Chinese literature. The time period for the literature search was from January 1990 to December 2013. The literature search strategy utilized the following keywords: “enteral nutrition” or “parenteral nutrition” and “hepatectomy”.
All prospective randomized controlled trials (RCTs) that compared EN and PN during the early stages after hepatectomy and satisfied the following criteria were included: the study must have examined at least one of several defined outcome measures, ie, nutritional complications, time to flatus, liver function after the end of nutrition, serum albumin level, and cost of nutrition; publication in full text form; and a sample size of at least 30, because findings from studies with small samples have poor reliability.
A study was excluded if it involved preoperative nutritional therapy, if it was an animal study, if it was not an RCT, if it was only published in abstract form, if it was a case report, if it did not provide recorded observations of any of the aforementioned outcome measures, if the patients had not had partial hepatectomy, or if random assignment was not strictly conducted.
Data extraction and quality assessment
In accordance with the inclusion and exclusion criteria for this systematic review, two literature assessors independently performed the literature screening, data extraction, and quality assessment. Disagreements regarding literature inclusion, data extraction, and quality assessment were resolved through discussion with the entire research group, which then made decisions regarding these differences of opinion. The extracted information included sample size, subject sex and age composition, manner and timing of providing EN, manner and timing of providing PN, occurrence of nutrition-related complications (such as diarrhea, bloating, and nutrition-related intravenous line infections), time to flatus, alanine aminotransferase and total bilirubin levels after the end of nutrition, serum albumin level, and the cost of nutrition.
Based on the quality assessment criteria for RCTs in version 5.2 of the Cochrane Handbook for Systematic Reviews of Interventions, the following aspects of the included studies were examined during the quality assessment process: use of an appropriate randomization method; use of a blinding method; use of a random allocation concealment method; and whether cases were lost to follow-up or dropped out of the study. For cases that were lost to follow-up or had dropped out of the study, the researchers examined whether intention-to-treat analysis was applied. Studies that satisfied all assessment criteria were categorized as class A studies, indicating that there was a minimal probability of biases relating to these criteria. Studies that satisfied at least one assessment criterion or partially satisfied multiple evaluation criteria (or if it was unclear how many assessment criteria were satisfied) were categorized as class B studies, indicating that there was a moderate probability of biases relating to these criteria. Studies that satisfied none of the assessment criteria were categorized as class C studies, indicating that there was a high probability of the presence of biases relating to these criteria.