Introduction: Superior vena cava (SVC) syndrome is an obstruction of blood flow through the superior vena cava, most commonly related to advanced malignant diseases. Patients usually present with cough, oropharyngeal edema, and stridor. Here we report a case of undiagnosed SVC syndrome causing unexpected circulatory collapse and progressive upper body cyanosis during surgery.
Description: A 44-year-old man, scheduled for hip fracture surgery, had a known diagnosis of liver cancer (HCC, 9.5 × 8.1 cm²) with abdominal lymph node metastasis. Immediately after the initiation of positive-pressure ventilation for anesthesia induction, his hemodynamics rapidly deteriorated, necessitating transfer to the ICU post-surgery. Aggressive fluid resuscitation via a jugular venous catheter did not resolve the circulatory collapse and appeared to exacerbate the edema, which was notably marked in the upper body, sparing the lower half. Suspecting the possibility of SVC syndrome, fluid resuscitation was transitioned to the femoral vein, which relieved the hypotension. Subsequent CTA revealed enlarged mediastinal lymph nodes compressing the SVC, which was confirmed by direct visualization of SVC compression. The circulatory collapse was deduced to arise from inadequate venous return secondary to positive-pressure ventilation during surgery, exacerbated by the obstructed SVC. An SVC stent was implanted, which improved the patient's hemodynamics and resolved the upper body edema. The patient was discharged from the intensive care unit four days later.
Discussion: This case highlights the importance of recognizing SVC syndrome in instances of unexplained circulatory collapse and progressive upper-body cyanosis following positive-pressure ventilation, especially in patients with pre-existing malignancies. As clinicians, when faced with unexpected circulatory collapse and upper body edema during surgery, we should consider the possibility of anatomic abnormalities including SVC syndrome. Timely diagnosis and interventions such as stent placement in the SVC can relieve the obstruction, improve hemodynamics, and resolve the associated symptoms.
