TPN Does Not Increase Infection Risk

TPN infection risk is a common concern among clinicians, but the evidence shows parenteral nutrition (PN) does not increase infection risk.

This long-standing misconception continues to circulate in hospitals, despite strong data and updated ASPEN parenteral nutrition guidelines showing otherwise. Recently, I heard from a clinical dietitian who said a doctor told her PN is “scary” and “not worth the risk.” It’s time to put this TPN infection myth to rest.

What the Evidence Says About TPN and Infection Risk

Here are a few key studies you can use when discussing parenteral nutrition infection risk with your team:

• “The provision of parenteral nutrition within 24 hours of ICU admission to critically ill patients with short-term relative contraindications to enteral nutrition did not result in significant differences in day-60 all-cause landmark mortality or ICU infection rates.” Doig GS, Simpson F, Sweetman EA, et al. Early Parenteral Nutrition in Critically Ill Patients With Short-term Relative Contraindications to Early Enteral Nutrition: A Randomized Controlled Trial. JAMA. 2013;309(20):2130–2138.
• “The results show that early EN and early PN do not differ with regard to the major clinical outcomes of mortality and infections, however PN resulted in fewer gut-related complications and hypoglycemic events.” Tian F, Doig GS. NUTRIREA-2 trial finds that early enteral nutrition and early parenteral nutrition do not differ with regards to major clinical outcomes. J Thorac Dis. 2018 Mar;10(3):1144-1146. 

This 2013 study demonstrated that supplemental parenteral nutrition (SPN) actually decreased infection risk in ICU patients:

• Optimisation of energy provision with supplemental parenteral nutrition in critically ill patients: a randomised controlled clinical trial. Heidegger, Claudia Paula et al. The Lancet, Volume 381, Issue 9864, 385 – 393. 

Note: SPN hasn’t really caught on in the US, but it’s increasingly common in Europe. This is further evidence that PN, when used appropriately, supports improved outcomes without raising infection risk.

What Do the ASPEN Guidelines Say About TPN Infection Risk?

The 2022 ASPEN Guidelines for Critically Ill Patients addressed this:

• Question 3: “In adult critically ill patients who are candidates for EN, does similar energy intake by PN vs EN as the primary feeding modality in the first week of critical illness impact clinical outcomes?”
• Recommendation: “There was no significant difference in clinical outcomes between early exclusive PN and EN during the first week of critical illness. As PN was not found to be superior to EN and no differences in harm were identified, we recommend that either PN or EN is acceptable.”
• Quality of evidence: High
• Strength of recommendation: Strong.

High-quality evidence and a strong recommendation are rare in consensus guidelines. 

Why Do Clinicians Still Believe TPN Increases Infection Risk?

Many outdated studies that linked parenteral nutrition to infection failed to control for hyperglycemia. Elevated glucose, not the PN itself, was the true driver of infection risk.

Additionally, we now use second- and third-generation lipid emulsions, which improve immune function and inflammatory profiles. Modern TPN solutions are customized and safer. In short: today’s PN is not the same as it used to be.

Unfortunately, AI is of no help here. If you Google “does TPN increase infection risk?” this is the result: