每日一题_2022.08.05

A 57-year-old man with a history of colon cancer on active chemotherapy, hypertension, hyperlipidemia, and coronary artery disease presents with sudden-onset shortness of breath. He was shaving at home when he suddenly developed acute dyspnea. In the emergency department, he is saturating 82% on 6 L/min nasal cannula, with respiratory rate 32 breaths/min, heart rate 124 beats/min, blood pressure 110/76 mm Hg. He is afebrile. He is started on high-flow nasal cannula oxygen at 20 L/min, with 60% fraction of inspired oxygen to keep his saturation above 92%. He says he feels better once high-flow oxygen is started, and his tachypnea resolves significantly. Chemistry is within normal limits, with bicarbonate of 21 mEq/L. Arterial blood gas analysis shows: pH 7.54, partial pressure of carbon dioxide 22 mm Hg, and partial pressure of oxygen 54 mm Hg. An emergent CT shows a central clot. An emergent echocardiogram shows a dilated and hypokinetic right ventricle. Laboratory results show: troponin I 1.2 ng/mL, creatinine 1.0 mg/dL, lactate 1.0 mmol/L.

Which of the following is the most appropriate next step?

A. IV thrombolytics

B. Therapeutic low-molecular-weight heparin

C. Intubation and mechanical ventilation

D. Inferior vena cava filter

E. Duplex ultrasound of lower extremities

答案解析：

该患者患有次大面积肺栓塞 (PE)，引起显著症状和右心室 (RV) 衰竭证据，但无血流动力学不稳定。溶栓剂唯一明确的适应症是大面积 PE 伴血流动力学不稳定。对于 RV 衰竭恶化、呼吸困难恶化或血流动力学恶化的次大面积PE，可根据具体情况考虑使用溶栓剂。PEITHO 研究表明，虽然溶栓治疗可适度改善死亡率/预防血流动力学不稳定，但颅外、颅和大出血显著增加。随后的荟萃分析证实了这一点，但也已知 RV 功能障碍和次大面积 PE 患者的死亡率是无 RV 功能障碍患者的2倍。此处不适合插管，因为患者在高流量鼻插管上显著改善。腿部双功能多普勒超声将在稍后指示，但不是最合适的下一步。此时不存在下腔静脉滤器的指征。

正确答案：B