What is the evidence for the use of parenteral nutrition (PN) in critically ill surgical patients: a systematic review and meta-analysis

Abstract

Background Malnutrition is associated with poor outcomes in surgical patients and corrective enteral feeding may not be possible. This is a particular problem in the acute setting where malnutrition is prevalent. The aim of this systematic review was to evaluate the use of parenteral nutrition (PN) in critically ill surgical patients. Methods This review was registered with PROSPERO (CRD42017079567). Searches of the CENTRAL, EMBASE, and MEDLINE databases were performed using a predefined strategy. Randomised trials published in English since 1995, reporting a comparison of PN vs any comparator in a critically ill surgical population were included. The primary outcome was mortality. Risk of bias was assessed using the Cochrane risk of bias tool and the Grading of Recommendations Assessment, Development and Evaluation assessment. Meta-analysis was performed using a random effects model to assess variation in mortality and length of stay. Results Fourteen RCTs were identified; standard PN was compared vs other forms of PN in ten studies, to PN with variable dose amino acids in one, and to enteral nutrition (EN) in three. In trials comparing glutamine-supplemented PN (PN-GLN) to PN, a non-significant reduction in mortality was noted (risk difference − 0.08. 95% CI − 0.17, 0.01, p = 0.08). A trend for a reduction in length of stay was seen in PN-GLN to PN comparator (mean reduction − 2.4, 95% CI − 7.19 to 2.32 days, I 2 = 92%). Impact on other outcome measures varied in direction of effect. Conclusions PN may offer benefit in critically ill surgical patients. The size and quality of studies lead to uncertainty around the estimates of clinical effect, meaning a robust trial is required.

Malnutrition, nutritional interventions and clinical outcomes of patients with acute small bowel obstruction: results from a national, multicentre, prospective audit

“…These trials typically included comparison with enteral feeding in predominantly medical populations, who often have normal intestinal function and continuity. There are few studies addressing this question exclusively in the surgical population, and those targeted at the surgical population are generally of low quality and do not make clinically useful comparisons for SBO 30. While propensity-matched analyses in this study did not demonstrate any effect from the use of PN, it is important to consider that this represents a sample of the subgroup who received PN in the study, meaning there is a high degree of selection bias.…”

“…Clinical sites should review local practices to reduce factors associated with variation in their unit, such as recording of malnutrition risk, access to dietitians and nutritional support teams. Research has not yet assessed the role of nutritional interventions, for example, early parenteral nutrition in patients with SBO30 and research in this area merits funding opportunities. Investment in hospital nutrition and dietetic services must accompany this.…”