英语语法分析

Pneumomediastinum may cause caval obstruction.

纵隔积气可能引起腔静脉梗阻。

Objective: To explore the treatment of Superior Vena Caval Syndrome caused by tumor.

目的：对肿瘤所致上腔静脉综合征的治疗进行探讨。

For most patients with PE, we recommend against the routine use of a vena caval filter in addition to anticoagulants (Grade 1a).

PE大部分患者，我们不推荐在抗凝基础上常规放置腔静脉滤器(1 A)。