Negative Echo study in shocked patient almost excludes pulmonary embolism as a differential .
Negative LL venous Doppler study does not exclude diagnosis of pulmonary embolism .However , in a pregnant lady , a positive study is sufficient for diagnosis of pulmonary embolism wthout the need for CT or VQ study .
Requesting D dimer in a pregnant or confirmed DVT or a post operative patient does not make any sense .
Starting heparin based on a strong clinical suspecion is a good practice , if there is no contraindication .
A suspicious findings on echo after post arrest or unstable patient are sufficient to start thrombolysis unless absolutely contraindicated .No need to go for CT .