Two days after a femur fracture, a client develops sudden hypoxemia, confusion, and a petechial rash over the upper chest. Which complication should the nurse suspect?

Fat embolism syndrome after a long-bone fracture classically combines respiratory compromise, neurologic change, and petechiae. The delayed onset and multisystem pattern fit fat embolism better than isolated atelectasis, wound infection, or limb-limited thrombosis.

Quick answer
Suspect fat embolism syndrome from the delayed combination of hypoxemia, confusion, and upper-body petechiae after a femur fracture.

Why this is correct
Marrow fat released after a long-bone injury can affect pulmonary, cerebral, and dermal microcirculation. The cluster of new oxygenation failure, altered mental status, and petechial rash is much more specific than any single finding alone.

Easy analogy or mental picture
Tiny fat droplets can scatter through several microvascular filters, producing lung, brain, and skin clues together. The filter comparison shows the multisystem pattern, but diagnosis still requires urgent clinical evaluation and exclusion of alternatives.

Memory hook
Long bone plus lungs, brain, and petechiae points to fat embolism syndrome.

NCLEX decision rule
After a long-bone or pelvic fracture, prioritize fat embolism syndrome when respiratory deterioration and neurologic change occur together, especially with petechiae. Escalate promptly rather than attributing the pattern to immobility alone.

Why the other choices are wrong
Atelectasis does not explain the characteristic petechial and neurologic combination. Local infection centers on the wound, while deep vein thrombosis usually produces limb findings and does not account for this full multisystem cluster.

Clinical Practice Guide
For Cast neurovascular compromise, compare the complete cue pattern with the client's current stability, ordered data, and expected nursing scope.

Caution
Do not choose an action from one isolated cue when the full scenario changes priority or safety.