TPN (total parenteral nutrition) delivers complete nutrition (dextrose, amino acids, lipids, electrolytes, vitamins, trace elements) via central venous access when the GI tract is non-functional for ≥7 days. Administered ONLY through dedicated PICC, subclavian, or internal jugular central lines (NEVER peripheral, NEVER through blood product port). Top nursing priorities: (1) Strict aseptic technique for all line access, (2) glucose monitoring q6h (target 6-10 mmol/L in critically ill), (3) daily metabolic labs, (4) never abruptly stop TPN (hypoglycemia risk). NCLEX trap: if TPN bag runs out, hang D10W at same rate to prevent hypoglycaemia — never leave line dry. On the exam, writers often pair stable-sounding options with unstable data—notice the mismatch before you commit. If the stem names a license or role, reread that line; scope errors are classic trap answers even when the clinical topic is familiar. Run a 60-second scan: breathing work and oxygenation, perfusion and end organs, neuro baseline, likely infection sources, and devices that can fail quietly. When two answers feel partly right, pick the one that reduces imminent harm and matches orders for the role...