Silent but lethal: intravenous gas visualized by point-of-care ultrasound

BACKGROUND: Venous gas embolus secondary to deep soft tissue infection is a rare but potentially fatal condition in emergency settings that requires urgent medical intervention. CASE PRESENTATION: We report a case of a 32-year-old female with an invasive mole undergoing chemotherapy who presented with fever and severe bilateral lower limb pain. Point-of-care ultrasound (POCUS) revealed gas emboli on B-mode and Doppler-mode imaging within the femoral veins and further detected emphysematous changes in adjacent intramuscular and subcutaneous tissues, suggesting critical infection and initiating immediate clinical reassessment. The patient was subsequently confirmed to have severe hypoxemia and sepsis, with computed tomography demonstrating extensive gas-forming lesions, ultimately leading to cardiac arrest despite advanced life support. CONCLUSION: This case highlights the critical role of POCUS in the rapid detection of intravascular gas and deep soft tissue infection in time-critical conditions.