Traditionally, it was common practice to fast patients scheduled for gastrointestinal surgery from 6 to 12 hours preoperatively until evidence of gut motility, signaled by bowel sounds and flatus, returned postoperatively.1 At that point, patients would commence a clear fluid diet and gradually advance to full fluids and then a regular diet.2 The rationale for this practice was the view that resting the bowel would decrease the risk of complications such as anastomotic dehiscence, aspiration pneumonia, bowel distension, bowel obstruction, and nausea and vomiting.3

A growing body of research identified that an extended period of fasting may actually cause adverse patient outcomes4 by depleting vital nutrients,5 increasing insulin resistance, and reducing muscle function.6 However, while some studies have reported that early enteral nutrition may improve gastrointestinal motility, nutritional status,7 and wound healing (including intestinal anastomosis) and reduce sepsis,6 other studies have shown no effect. Additionally, in a systematic review of 11 studies, Ahmed et al8 demonstrated that these somewhat contradictory results may have contributed to inconsistent compliance (from 13% to 100%) with early postoperative feeding regimens.

Against this background, and the fact that previous reviews of early postoperative feeding were limited by the available evidence, an updated review was therefore warranted.

OBJECTIVE

The objective of this review, an update of one undertaken in 2011, was to assess whether commencement of postoperative enteral nutrition (within 24 hours of surgery), oral intake, or tube feeding (gastric, duodenal, or jejunal), compared with delayed nutritional support, is associated with reduced length of hospital stay (LOS), fewer complications, mortality, and adverse events in patients undergoing lower gastrointestinal surgery.

INTERVENTION/METHODS

Types of Studies

Randomized controlled trials, including cluster randomized controlled trials, comparing early commencement (within 24 hours) of enteral nutrition (defined as oral intake or gastric, duodenal, or jejunal tube feeding) and containing energy (carbohydrate, protein, or fat) with no feeding in adult participants undergoing acute or elective lower gastrointestinal surgery were included in the review.

Trials were considered irrespective of whether blinding or placebo treatment was performed. Studies reporting comparison of treatment between parenteral nutrition, enteral nutrition, and controls were included if data could be provided separately for patients in the feeding group and control group.

Types of Participants

Adults 18 years or older with malignant or benign disease undergoing lower gastrointestinal surgery were included. Lower gastrointestinal surgery was classified as where an anastomosis was formed distal to the ligament of Treitz.

Types of Interventions

Interventions included enteral feeding, orally or via a tube, given within 24 hours postoperatively. The control arm included traditional management defined as no intake orally or via a tube, containing energy before return of bowel function.

Primary Outcome Measures

* Length of stay

* Postoperative complications such as wound infections, intra-abdominal abscesses, anastomotic dehiscence, and pneumonia

Secondary Outcome Measures

* Mortality

* Adverse events (nausea, vomiting)

* Quality of life

RESULTS

Six new trials, along with the original 11 trials, with a total sample of 1437 participants were included in the review.

Primary Outcome 1: LOS

Length of hospital stay was reported in 16 studies (1346 participants). There was a significant difference between the LOS for the intervention groups (4-16 days) and the control groups (6.6-23.5 days; mean difference, 1.95 days; 95% confidence interval, -2.99 to -0.91; P < .001). However, there was heterogeneity across the trials indicating that the overall quality of evidence for LOS was low.

Primary Outcome 2: Postoperative Complications

There were no differences in the incidence of postoperative complications, including

* rates of wound infection (reported in 12 studies with 1181 participants),

* intra-abdominal abscesses (reported in 6 studies with 554 participants),

* anastomotic leakage/dehiscence (reported in 13 studies with 1232 participants), and

* pneumonia (reported in 10 studies with 954 participants).

Each of these studies had low-quality or very low-quality evidence.1

Secondary Outcome 1: Mortality

There were no significant between-group differences in mortality rates (reported in 12 studies with 1179 participants), with a range of none to 6.7% in the intervention groups and none to 19% in the control groups. Each of these studies had low-quality evidence.1 The most commonly reported causes of death were anastomotic leakage, sepsis, and acute myocardial infarction.

Secondary Outcome 2: Adverse Events

In the studies that reported on nausea and vomiting, there were no significant between-group differences reported:

* vomiting (reported in 7 studies with 613 participants),

* nausea (reported in 2 studies with 118 participants), and

* nausea and vomiting combined (reported in 4 studies).

Each of these studies had low-quality or very low-quality evidence.1 A number of trials reported other adverse events such as distention, diarrhea, hyporexia, and small bowel obstruction, which were outside the scope of this review.

Secondary Outcome 3: Quality of Life

In the only study that reported on quality of life, there was no difference between groups at 30 days after discharge; however, this study had very low-quality evidence.

CONCLUSIONS

The key outcome from this review was the significant difference of 1.95 days between the postoperative LOS for the intervention and the control groups. However, Herbert et al1 note that this result should be considered with caution due to substantial heterogeneity, risk of bias, and low-quality evidence. Consequently, this result, along with the inconclusive outcomes with regard to the other primary and secondary outcomes, justifies the need for further trials of high quality in this area.

IMPLICATIONS FOR PRACTICE

Despite the inconclusive findings for all outcomes apart from LOS evident in this review, previous trials (albeit animal and human) have indicated that early postoperative feeding of patients undergoing gastrointestinal surgery may improve bowel motility, nutritional status,7 and wound healing, as well as reducing the risk of sepsis.6 These findings, although limited, should be used to inform and improve the consistency of clinical practice with regard to early postoperative feeding regimens.

References