A 2017 report aimed to describe factors associated with fungemia in patients with parenteral nutrition. The recommendation from multiple organizations such as the Infection Control Practices Advisory Committee and the European Society for Clinical Nutrition & Metabolism is to remove or change lipids for every 24 hours to decrease the risk of fungal infections, although the authors argue this recommendation may be based on outdated information. While thought to pose a risk of increased fungal infection when added to parenteral nutrition, the review notes that literature supporting this claim is ambiguous, lacking sufficient recent, good-quality evidence. Ultimately, the authors suggest that lipids in parenteral nutrition do not increase the risk of fungal infections and that withholding parenteral nutrition for this specific reason may actually result in patient harm. Strict protocols regarding catheter placement and utilization of a nutrition support team to educate medical personnel may help reduce overall risk of infection due to parenteral nutrition in general. Future studies are still needed to fully elucidate the relationship between fungemia and parenteral nutrition, with the author suggesting that factors such as the pH and the osmolarity of the parenteral nutrition, presence of hyperglycemia, and increased manipulation of the bag may play a bigger role in increased risk of fungal infections rather than from the parenteral nutrition alone. [1]
Other related discussion articles also argue that the risk of increased fungal infections due to lipid emulsions is erroneous, likely due to outdated information compiled from a time period when parenteral nutrition administration may not have been conducted with proper equipment and protocols, such as inadequate catheter care and poor techniques for achieving glucose control. The sole presence of a central venous catheter (CVC) and its connection point is associated with increased infection, even with ideal standard of care. Additionally, animal models suggest the very absence of enteral feeding may increase risk of fungal infection due to resulting gut atrophy and translocation of microorganisms. Authors discuss the lack of clinical studies specifically investigating Candida-related bloodstream infections associated with lipid-containing or lipid-free parenteral nutrition, hypothesizing that such a comparison may not be viable due to ethical reasons associated with forgoing a vital component such as lipids from parenteral nutrition. Some data demonstrates that Candida species can proliferate in all parenteral nutrition solutions, regardless of presence of lipids, and an in vitro study was discussed, which demonstrated that inclusion of lipid emulsion was not found to impact growth of C. albicans, further suggesting concerns regarding increased risk of fungal infection with modern day compounded practices is unfounded. Furthermore, recent advances such as use of multi chamber bags and peripherally inserted central catheters have been shown to decrease rates of bloodstream infections, as well as standards of care such as hand hygiene and maximal barrier precautions during insertion of catheters. Ultimately, if bloodstream infections occur in a patient receiving parenteral nutrition, currently available data suggests that the cause is likely to be independent of the infusates contained within the product, lipid or otherwise. [2]
A 2016 systematic review and meta-analysis assess the effect of lipid emulsion on microbial growth in parenteral nutrition. A total of 24 studies were included; notably, the authors discussed that some guidelines related to microbial growth and use of parenteral nutrition utilized more limited and weaker data. Amongst the included studies for the present review, compositions of infusates varied widely and compositions of lipid parenteral nutrition rarely matched that of lipid-free parenteral nutrition. Lipid concentrations, energy density, pH, osmolarity, and other factors may have also varied. The effects of nutrients on growth ratio (GR) was assessed, finding that presence of lipid in parenteral nutrition at fixed glucose concentrations did not significantly increase GR of Candida albicans (p= 0.352). [3]
Additionally, a 2012 comparative retrospective study may be insightful, despite not specifically assessing incidence of fungemia. The study included 4,669 patients to compare use of commercially available premixed parenteral nutrition with or without lipids and risk of incident bloodstream infections. Data regarding use of nutrition was compiled via charge codes. Lipid emulsions were administered through a separate line or piggybacked through the parenteral nutrition line. After adjusting for patients baseline characteristics, risk factors, and potential confounders, results indicated that no significant differences were observed in overall risk of bacterial infections (51.4% vs. 53.5%; odds ratio [OR] 1.11, 95% confidence interval [CI] 0.96 to 1.27) or bloodstream infections (19.6% vs. 19.2%; OR 0.97, 95% CI 0.81 to 1.16) for patients receiving nutrition without lipids vs. those with lipids, respectfully. Unfortunately, a subgroup analysis investigating risk of Candida related infections was not conducted. [4]