Parenteral nutrition and supplemental parenteral nutrition: should we use more?

PURPOSE OF REVIEW: This review examines when parenteral nutrition (PN) (inclusive of total (TPN), supplemental (SPN), or peripheral (PPN)) may be provided in intensive care unit (ICU). We discuss adapting PN across metabolic phases, including early and late acute phases in ICU, post-ICU, and ward recovery. RECENT FINDINGS: Given emerging data, it is more likely that historical negative sequelae associated with PN were driven by overfeeding than the feeding route itself. With conservative energy delivery and strict aseptic care, TPN/SPN is likely as safe as enteral nutrition (EN) in modern ICU settings. TPN should be considered when the gastrointestinal (GI) tract is non-functional, and SPN when EN is insufficient or not tolerated. Furthermore, amino acid uptake and muscle responses are comparable. Substantial energy and protein deficits persist post-ICU, particularly with oral intake alone, highlighting SPN's role to support rehabilitation. PPN may provide short-term strategies to bridge inadequate nutrition. SUMMARY: PN prescriptions should consider individual patient needs and phase of illness. In the ICU, PN should be considered when EN is not feasible or insufficient, particularly in later phase. Post-ICU and postoperatively, PN may support recovery when oral intake is poor or EN is impossible.