Peripheral parenteral nutrition in surgery - a systematic review and meta-analysis.

BACKGROUND: Peripheral parenteral nutrition (PPN) refers to the delivery of artificial nutrition via a peripheral intravenous cannula. As a nutritional intervention it remains under-utilised in peri-operative care. This is despite purported advantages which includes avoiding the risks associated with central venous lines and preventing potential delays to the initiation of nutrition support. This systematic review and meta-analysis will detail the available evidence for PPN use in surgery.

METHODS: A comprehensive search of the EMBASE and Medline databases was undertaken to identify randomised control trials (RCTs) involving PPN use in surgical patients published until July 30th 2022. Three domains of PPN use were reviewed including: PPN compared to crystalloid intravenous fluids on nutritional and clinical outcomes; PPN compared to Central PN (CPN) on nutritional outcomes and complications; and strategies to prevent thrombophlebitis associated with PPN.

RESULTS: The meta-analysis included 8 studies which included 698 patients. Use of PPN led to reduced post-operative weight loss (% body weight change) with a mean difference of -1.45% (95% CI -2.9 to -0.01, p = 0.05). There was no statistically significant difference in terms of length of stay, infectious/non-infectious complications, surgical site infections or phlebitis. 42 RCTs were included in the systematic review. 14 RCTs compared PPN to crystalloid infusion. There was significant heterogeneity in the trial populations, interventions and measured outcomes. Most trials found that PPN may improve nitrogen balance and positively impact nutritional markers. Quality of life and post-operative complications were either improved or no difference found in trials assessing these outcomes. Four RCTs showed that PPN is a safe and feasible alternative to CPN. 22 RCTs reported on measures that may impact on thrombophlebitis rates associated with PPN. These included lower osmolality of PPN solution, cyclical PPN delivery, use of a small gauge polyurethane cannula in an upper limb vein, addition of heparin/hydrocortisone to PPN solutions and placement of a GTN patch over infusion sites.

CONCLUSION: PPN is a safe and effective mode of delivery of peri-operative nutrition. It is a feasible short-term alternative to central-line delivered PN. There are a number of strategies to reduce thrombophlebitis associated with PPN use. Further high-quality RCTs are required to assess the use of PPN in contemporary surgical practice.